84 results on '"Triccas, JA"'
Search Results
2. Neutrophil conversion to a tumor-killing phenotype underpins effective microbial therapy.
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Yam, AO, Bailey, J, Lin, F, Jakovija, A, Youlten, SE, Counoupas, C, Gunzer, M, Bald, T, Woodruff, TM, Triccas, JA, Goldstein, LD, Gallego-Ortega, D, Grey, ST, Chtanova, T, Yam, AO, Bailey, J, Lin, F, Jakovija, A, Youlten, SE, Counoupas, C, Gunzer, M, Bald, T, Woodruff, TM, Triccas, JA, Goldstein, LD, Gallego-Ortega, D, Grey, ST, and Chtanova, T
- Abstract
The inflammatory microenvironment of solid tumors creates a pro-tumorigenic milieu that resembles chronic inflammation akin to a subverted wound healing response. Here we investigated the effect of converting the tumor microenvironment from a chronically inflamed state to one of acute microbial inflammation by injecting microbial bioparticles directly into tumors. Intratumoral microbial bioparticle injection led to rapid and dramatic changes in the tumor immune composition, the most striking of which was a substantial increase in the presence of activated neutrophils. In situ photoconversion and intravital microscopy indicated that tumor neutrophils transiently switched from sessile producers of vascular endothelial growth factor to highly motile neutrophils that clustered to make neutrophil-rich domains in the tumor. The neutrophil clusters remodeled tumor tissue and repressed tumor growth. Single cell transcriptional analysis of microbe-stimulated neutrophils showed a profound shift in gene expression towards heightened activation and anti-microbial effector function. Microbe-activated neutrophils also upregulated chemokines known to regulate neutrophil and CD8+ T cell recruitment. Microbial therapy also boosted CD8+ T cell function and enhanced the therapeutic benefit of checkpoint inhibitor therapy in tumor-bearing mice and provided protection in a model of tumor recurrence. These data indicate that one of the major effector mechanisms of microbial therapy is the conversion of tumor neutrophils from a wound healing to an acutely activated cytotoxic phenotype, highlighting a rationale for broader deployment of microbial therapy in the treatment of solid cancers.
- Published
- 2023
3. Neutralising antibody titres as predictors of protection against SARS-CoV-2 variants and the impact of boosting: a meta-analysis
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Cromer, D, Steain, M, Reynaldi, A, Schlub, TE, Wheatley, AK, Juno, JA, Kent, SJ, Triccas, JA, Khoury, DS, Davenport, MP, Cromer, D, Steain, M, Reynaldi, A, Schlub, TE, Wheatley, AK, Juno, JA, Kent, SJ, Triccas, JA, Khoury, DS, and Davenport, MP
- Abstract
BACKGROUND: Several SARS-CoV-2 variants of concern have been identified that partly escape serum neutralisation elicited by current vaccines. Studies have also shown that vaccines demonstrate reduced protection against symptomatic infection with SARS-CoV-2 variants. We explored whether in-vitro neutralisation titres remain predictive of vaccine protection from infection with SARS-CoV-2 variants. METHODS: In this meta-analysis, we analysed published data from 24 identified studies on in-vitro neutralisation and clinical protection to understand the loss of neutralisation to existing SARS-CoV-2 variants of concern. We integrated the results of this analysis into our existing statistical model relating in-vitro neutralisation to protection (parameterised on data from ancestral virus infection) to estimate vaccine efficacy against SARS-CoV-2 variants. We also analysed data on boosting of vaccine responses and use the model to predict the impact of booster vaccination on protection against SARS-CoV-2 variants. FINDINGS: The neutralising activity against the ancestral SARS-CoV-2 was highly predictive of neutralisation of variants of concern. Decreases in neutralisation titre to the alpha (1·6-fold), beta (8·8-fold), gamma (3·5-fold), and delta (3·9-fold) variants (compared to the ancestral virus) were not significantly different between different vaccines. Neutralisation remained strongly correlated with protection from symptomatic infection with SARS-CoV-2 variants of concern (r S=0·81, p=0·0005) and the existing model remained predictive of vaccine efficacy against variants of concern once decreases in neutralisation to the variants of concern were incorporated. Modelling of predicted vaccine efficacy against variants over time suggested that protection against symptomatic infection might decrease below 50% within the first year after vaccination for some vaccines. Boosting of previously infected individuals with existing vaccines (which target ancestral virus) is predi
- Published
- 2022
4. Discovery of Anti-tubercular Analogues of Bedaquiline with Modified A-, B- and C-Ring Subunits
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Barbaro, L, Nagalingam, G, Triccas, JA, Tan, L, West, NP, Priebbenow, DL, Baell, JB, Barbaro, L, Nagalingam, G, Triccas, JA, Tan, L, West, NP, Priebbenow, DL, and Baell, JB
- Abstract
To date, the clinical use of the anti-tubercular therapy bedaquiline has been somewhat limited due to safety concerns. Recent investigations determined that modification of the B- and C-ring units of bedaquiline delivered new diarylquinolines (for example TBAJ-587) with potent anti-tubercular activity yet an improved safety profile due to reduced affinity for the hERG channel. Building on our recent discovery that substitution of the quinoline motif (the A-ring subunit) for C5-aryl pyridine groups within bedaquiline analogues led to retention of anti-tubercular activity, we investigated the concurrent modification of A-, B- and C-ring units within bedaquiline variants. This led to the discovery that 4-trifluoromethoxyphenyl and 4-chlorophenyl pyridyl analogues of TBAJ-587 retained relatively potent anti-tubercular activity and for the 4-chlorophenyl derivative in particular, a significant reduction in hERG inhibition relative to bedaquiline was achieved, demonstrating that modifications of the A-, B- and C-ring units within the bedaquiline structure is a viable strategy for the design of effective, yet safer (and less lipophilic) anti-tubercular compounds.
- Published
- 2022
5. Rough and smooth variants of Mycobacterium abscessus are differentially controlled by host immunity during chronic infection of adult zebrafish.
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Kam, JY, Hortle, E, Krogman, E, Warner, SE, Wright, K, Luo, K, Cheng, T, Manuneedhi Cholan, P, Kikuchi, K, Triccas, JA, Britton, WJ, Johansen, MD, Kremer, L, Oehlers, SH, Kam, JY, Hortle, E, Krogman, E, Warner, SE, Wright, K, Luo, K, Cheng, T, Manuneedhi Cholan, P, Kikuchi, K, Triccas, JA, Britton, WJ, Johansen, MD, Kremer, L, and Oehlers, SH
- Abstract
Prevalence of Mycobacterium abscessus infections is increasing in patients with respiratory comorbidities. After initial colonisation, M. abscessus smooth colony (S) variants can undergo an irreversible genetic switch into highly inflammatory, rough colony (R) variants, often associated with a decline in pulmonary function. Here, we use an adult zebrafish model of chronic infection with R and S variants to study M. abscessus pathogenesis in the context of fully functioning host immunity. We show that infection with an R variant causes an inflammatory immune response that drives necrotic granuloma formation through host TNF signalling, mediated by the tnfa, tnfr1 and tnfr2 gene products. T cell-dependent immunity is stronger against the R variant early in infection, and regulatory T cells associate with R variant granulomas and limit bacterial growth. In comparison, an S variant proliferates to high burdens but appears to be controlled by TNF-dependent innate immunity early during infection, resulting in delayed granuloma formation. Thus, our work demonstrates the applicability of adult zebrafish to model persistent M. abscessus infection, and illustrates differences in the immunopathogenesis induced by R and S variants during granulomatous infection.
- Published
- 2022
6. Mucosal immunization with a delta-inulin adjuvanted recombinant spike vaccine elicits lung-resident immune memory and protects mice against SARS-CoV-2.
- Author
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Stewart, EL, Counoupas, C, Johansen, MD, Nguyen, DH, Miemczyk, S, Hansbro, NG, Ferrell, KC, Ashhurst, A, Alca, S, Ashley, C, Steain, M, Britton, WJ, Hansbro, PM, Petrovsky, N, Triccas, JA, Stewart, EL, Counoupas, C, Johansen, MD, Nguyen, DH, Miemczyk, S, Hansbro, NG, Ferrell, KC, Ashhurst, A, Alca, S, Ashley, C, Steain, M, Britton, WJ, Hansbro, PM, Petrovsky, N, and Triccas, JA
- Abstract
Multiple SARS-CoV-2 vaccine candidates have been approved for use and have had a major impact on the COVID-19 pandemic. There remains, however, a significant need for vaccines that are safe, easily transportable and protective against infection, as well as disease. Mucosal vaccination is favored for its ability to induce immune memory at the site of infection, making it appealing for SARS-CoV-2 vaccine strategies. In this study we performed in-depth analysis of the immune responses in mice to a subunit recombinant spike protein vaccine formulated with the delta-inulin adjuvant Advax when administered intratracheally (IT), versus intramuscular delivery (IM). Both routes produced robust neutralizing antibody titers (NAb) and generated sterilizing immunity against SARS-CoV-2. IT delivery, however, produced significantly higher systemic and lung-local NAb that resisted waning up to six months post vaccination, and only IT delivery generated inducible bronchus-associated lymphoid tissue (iBALT), a site of lymphocyte antigen presentation and proliferation. This was coupled with robust and long-lasting lung tissue-resident memory CD4+ and CD8+ T cells that were not observed in IM-vaccinated mice. This study provides a detailed view of the lung-resident cellular response to IT vaccination against SARS-CoV-2 and demonstrates the importance of delivery site selection in the development of vaccine candidates.
- Published
- 2022
7. Mucosal TLR2-activating protein-based vaccination induces potent pulmonary immunity and protection against SARS-CoV-2 in mice.
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Ashhurst, AS, Johansen, MD, Maxwell, JWC, Stockdale, S, Ashley, CL, Aggarwal, A, Siddiquee, R, Miemczyk, S, Nguyen, DH, Mackay, JP, Counoupas, C, Byrne, SN, Turville, S, Steain, M, Triccas, JA, Hansbro, PM, Payne, RJ, Britton, WJ, Ashhurst, AS, Johansen, MD, Maxwell, JWC, Stockdale, S, Ashley, CL, Aggarwal, A, Siddiquee, R, Miemczyk, S, Nguyen, DH, Mackay, JP, Counoupas, C, Byrne, SN, Turville, S, Steain, M, Triccas, JA, Hansbro, PM, Payne, RJ, and Britton, WJ
- Abstract
Current vaccines against SARS-CoV-2 substantially reduce mortality, but protection against infection is less effective. Enhancing immunity in the respiratory tract, via mucosal vaccination, may provide protection against infection and minimise viral spread. Here, we report testing of a subunit vaccine in mice, consisting of SARS-CoV-2 Spike protein with a TLR2-stimulating adjuvant (Pam2Cys), delivered to mice parenterally or mucosally. Both routes of vaccination induce substantial neutralising antibody (nAb) titres, however, mucosal vaccination uniquely generates anti-Spike IgA, increases nAb in the serum and airways, and increases lung CD4+ T-cell responses. TLR2 is expressed by respiratory epithelia and immune cells. Using TLR2 deficient chimeric mice, we determine that TLR2 expression in either compartment facilitates early innate responses to mucosal vaccination. By contrast, TLR2 on hematopoietic cells is essential for optimal lung-localised, antigen-specific responses. In K18-hACE2 mice, vaccination provides complete protection against disease and sterilising lung immunity against SARS-CoV-2, with a short-term non-specific protective effect from mucosal Pam2Cys alone. These data support mucosal vaccination as a strategy to improve protection in the respiratory tract against SARS-CoV-2 and other respiratory viruses.
- Published
- 2022
8. Virulence Mechanisms of Mycobacterium abscessus: Current Knowledge and Implications for Vaccine Design.
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Ferrell, KC, Johansen, MD, Triccas, JA, Counoupas, C, Ferrell, KC, Johansen, MD, Triccas, JA, and Counoupas, C
- Abstract
Mycobacterium abscessus is a member of the non-tuberculous mycobacteria (NTM) group, responsible for chronic infections in individuals with cystic fibrosis (CF) or those otherwise immunocompromised. While viewed traditionally as an opportunistic pathogen, increasing research into M. abscessus in recent years has highlighted its continued evolution into a true pathogen. This is demonstrated through an extensive collection of virulence factors (VFs) possessed by this organism which facilitate survival within the host, particularly in the harsh environment of the CF lung. These include VFs resembling those of other Mycobacteria, and non-mycobacterial VFs, both of which make a notable contribution in shaping M. abscessus interaction with the host. Mycobacterium abscessus continued acquisition of VFs is cause for concern and highlights the need for novel vaccination strategies to combat this pathogen. An effective M. abscessus vaccine must be suitably designed for target populations (i.e., individuals with CF) and incorporate current knowledge on immune correlates of protection against M. abscessus infection. Vaccination strategies must also build upon lessons learned from ongoing efforts to develop novel vaccines for other pathogens, particularly Mycobacterium tuberculosis (M. tb); decades of research into M. tb has provided insight into unconventional and innovative vaccine approaches that may be applied to M. abscessus. Continued research into M. abscessus pathogenesis will be critical for the future development of safe and effective vaccines and therapeutics to reduce global incidence of this emerging pathogen.
- Published
- 2022
9. A single dose, BCG-adjuvanted COVID-19 vaccine provides sterilising immunity against SARS-CoV-2 infection.
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Counoupas, C, Johansen, MD, Stella, AO, Nguyen, DH, Ferguson, AL, Aggarwal, A, Bhattacharyya, ND, Grey, A, Hutchings, O, Patel, K, Siddiquee, R, Stewart, EL, Feng, CG, Hansbro, NG, Palendira, U, Steain, MC, Saunders, BM, Low, JKK, Mackay, JP, Kelleher, AD, Britton, WJ, Turville, SG, Hansbro, PM, Triccas, JA, Counoupas, C, Johansen, MD, Stella, AO, Nguyen, DH, Ferguson, AL, Aggarwal, A, Bhattacharyya, ND, Grey, A, Hutchings, O, Patel, K, Siddiquee, R, Stewart, EL, Feng, CG, Hansbro, NG, Palendira, U, Steain, MC, Saunders, BM, Low, JKK, Mackay, JP, Kelleher, AD, Britton, WJ, Turville, SG, Hansbro, PM, and Triccas, JA
- Abstract
Global control of COVID-19 requires broadly accessible vaccines that are effective against SARS-CoV-2 variants. In this report, we exploit the immunostimulatory properties of bacille Calmette-Guérin (BCG), the existing tuberculosis vaccine, to deliver a vaccination regimen with potent SARS-CoV-2-specific protective immunity. Combination of BCG with a stabilised, trimeric form of SARS-CoV-2 spike antigen promoted rapid development of virus-specific IgG antibodies in the blood of vaccinated mice, that was further augmented by the addition of alum. This vaccine formulation, BCG:CoVac, induced high-titre SARS-CoV-2 neutralising antibodies (NAbs) and Th1-biased cytokine release by vaccine-specific T cells, which correlated with the early emergence of T follicular helper cells in local lymph nodes and heightened levels of antigen-specific plasma B cells after vaccination. Vaccination of K18-hACE2 mice with a single dose of BCG:CoVac almost completely abrogated disease after SARS-CoV-2 challenge, with minimal inflammation and no detectable virus in the lungs of infected animals. Boosting BCG:CoVac-primed mice with a heterologous vaccine further increased SARS-CoV-2-specific antibody responses, which effectively neutralised B.1.1.7 and B.1.351 SARS-CoV-2 variants of concern. These findings demonstrate the potential for BCG-based vaccination to protect against major SARS-CoV-2 variants circulating globally.
- Published
- 2021
10. Rapid Antibacterial Activity of Cannabichromenic Acid against Methicillin-Resistant Staphylococcus aureus
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Galletta M, Reekie TA, Nagalingam G, Bottomley AL, Harry EJ, Kassiou M, and Triccas JA
- Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) has proven to be an imminent threat to public health, intensifying the need for novel therapeutics. Previous evidence suggests that cannabinoids harbour potent antibacterial activity. In this study, a group of previously inaccessible phytocannabinoids and synthetic analogues were examined for potential antibacterial activity. The minimum inhibitory concentrations and dynamics of bacterial inhibition, determined through resazurin reduction and time-kill assays, revealed the potent antibacterial activity of the phytocannabinoids against gram-positive antibiotic-resistant bacterial species, including MRSA. One phytocannabinoid, cannabichromenic acid (CBCA), demonstrated faster and more potent bactericidal activity than vancomycin, the currently recommended antibiotic for the treatment of MRSA infections. Such bactericidal activity was sustained against low-and high-dose inoculums as well as exponential- and stationary-phase MRSA cells. Further, mammalian cell viability was maintained in the presence of CBCA. Finally, microscopic evaluation suggests that CBCA may function through the degradation of the bacterial lipid membrane and alteration of the bacterial nucleoid. The results of the current study provide encouraging evidence that cannabinoids may serve as a previously unrecognised resource for the generation of novel antibiotics active against MRSA.
- Published
- 2020
11. A single dose, BCG-adjuvanted COVID-19 vaccine provides sterilizing immunity against SARS-CoV-2 infection in mice
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Counoupas, C, Johansen, MD, Stella, AO, Nguyen, DH, Ferguson, AL, Aggarwal, A, Bhattacharyya, ND, Grey, A, Patel, K, Siddiquee, R, Stewart, EL, Feng, CG, Hansbro, NG, Palendira, U, Steain, MC, Saunders, BM, Low, JKK, Mackay, JP, Kelleher, AD, Britton, WJ, Turville, SG, Hansbro, PM, Triccas, JA, Counoupas, C, Johansen, MD, Stella, AO, Nguyen, DH, Ferguson, AL, Aggarwal, A, Bhattacharyya, ND, Grey, A, Patel, K, Siddiquee, R, Stewart, EL, Feng, CG, Hansbro, NG, Palendira, U, Steain, MC, Saunders, BM, Low, JKK, Mackay, JP, Kelleher, AD, Britton, WJ, Turville, SG, Hansbro, PM, and Triccas, JA
- Published
- 2020
12. Antitubercular Bis-Substituted Cyclam Derivatives: Structure-Activity Relationships and in Vivo Studies.
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Spain, M, Wong, JK-H, Nagalingam, G, Batten, JM, Hortle, E, Oehlers, SH, Jiang, XF, Murage, HE, Orford, JT, Crisologo, P, Triccas, JA, Rutledge, PJ, Todd, MH, Spain, M, Wong, JK-H, Nagalingam, G, Batten, JM, Hortle, E, Oehlers, SH, Jiang, XF, Murage, HE, Orford, JT, Crisologo, P, Triccas, JA, Rutledge, PJ, and Todd, MH
- Abstract
We recently reported the discovery of nontoxic cyclam-derived compounds that are active against drug-resistant Mycobacterium tuberculosis. In this paper we report exploration of the structure-activity relationship for this class of compounds, identifying several simpler compounds with comparable activity. The most promising compound identified, possessing significantly improved water solubility, displayed high levels of bacterial clearance in an in vivo zebrafish embryo model, suggesting this compound series has promise for in vivo treatment of tuberculosis.
- Published
- 2018
13. Intranasal Self-Adjuvanted Lipopeptide Vaccines Elicit High Antibody Titers and Strong Cellular Responses against SARS-CoV-2.
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Maxwell JWC, Stockdale S, Stewart EL, Ashley CL, Smith LJ, Steain M, Triccas JA, Byrne SN, Britton WJ, Ashhurst AS, and Payne RJ
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- Animals, Mice, Female, Humans, Mice, Inbred BALB C, Adjuvants, Vaccine administration & dosage, Vaccines, Subunit immunology, Vaccines, Subunit administration & dosage, Immunity, Cellular, Antibodies, Neutralizing immunology, Antibodies, Neutralizing blood, CD8-Positive T-Lymphocytes immunology, CD4-Positive T-Lymphocytes immunology, SARS-CoV-2 immunology, Administration, Intranasal, COVID-19 Vaccines immunology, COVID-19 Vaccines administration & dosage, Spike Glycoprotein, Coronavirus immunology, COVID-19 prevention & control, COVID-19 immunology, Lipopeptides immunology, Lipopeptides administration & dosage, Antibodies, Viral immunology, Antibodies, Viral blood, Adjuvants, Immunologic administration & dosage, Adjuvants, Immunologic pharmacology
- Abstract
Despite concerted efforts to tackle the COVID-19 pandemic, the persistent transmission of SARS-CoV-2 demands continued research into novel vaccination strategies to combat the virus. In light of this, intranasally administered peptide vaccines, particularly those conjugated to an immune adjuvant to afford so-called "self-adjuvanted vaccines", remain underexplored. Here, we describe the synthesis and immunological evaluation of self-adjuvanting peptide vaccines derived from epitopes of the spike glycoprotein of SARS-CoV-2 covalently fused to the potent adjuvant, Pam
2 Cys, that targets toll-like receptor 2 (TLR2). When administered intranasally, these vaccines elicited a strong antigen-specific CD4+ and CD8+ T-cell response in the lungs as well as high titers of IgG and IgA specific to the native spike protein of SARS-CoV-2. Unfortunately, serum and lung fluid from mice immunized with these vaccines failed to inhibit viral entry in spike-expressing pseudovirus assays. Following this, we designed and synthesized fusion vaccines composed of the T-cell epitope discovered in this work, covalently fused to epitopes of the receptor-binding domain of the spike protein reported to be neutralizing. While antibodies elicited against these fusion vaccines were not neutralizing, the T-cell epitope retained its ability to stimulate strong antigen-specific CD4+ lymphocyte responses within the lungs. Given the Spike(883-909) region is still completely conserved in SARS-CoV-2 variants of concern and variants of interest, we envision the self-adjuvanting vaccine platform reported here may inform future vaccine efforts.- Published
- 2024
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14. Immunogenicity and Protective Efficacy of a Multi-Antigen Mycobacterium tuberculosis Subunit Vaccine in Mice.
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Nisa A, Pinto R, Britton WJ, Triccas JA, and Counoupas C
- Abstract
There is an urgent need for an effective TB vaccine capable of controlling both acute and chronic Mycobacterium tuberculosis infection in populations with diverse genetic backgrounds. In this study, we characterised the immunogenicity and protective efficacy of a novel protein-in-adjuvant subunit vaccine. The protein component is a fusion protein of three different M. tuberculosis antigens, which we termed CysVac5: CysD, a major component of the M. tuberculosis sulfate activation pathway that is highly expressed during the chronic stage of M. tuberculosis infection, is fused with two major secreted mycobacterial antigens, Ag85B and MPT83. Vaccination of C57BL/6 mice with CysVac5, formulated in a monophosphoryl lipid A (MPLA) and dimethyldioctadecylammonium (DDA) adjuvant combination, resulted in the potent generation of polyfunctional CD4
+ T cells secreting multiple cytokines, including IFN-γ, IL-2, TNF and IL-17, against each of the three components of the fusion protein. Furthermore, vaccination with CysVac5-MPLA/DDA conferred significant protection against infection in mouse lungs, which was greater than that afforded by BCG at extended time points post-challenge. The generation of antigen-specific and protective immunity was also observed in CysVac5 vaccinated BALB/c mice, indicating the vaccine could display efficacy across multiple genetic backgrounds. These results indicate that the CysVac5 vaccine has broad immunogenicity, is effective in controlling both acute and chronic phases of M. tuberculosis infection in mice, and warrants further investigation to assess its potential to control pulmonary TB.- Published
- 2024
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15. Dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN) is a cellular receptor for delta inulin adjuvant.
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Stewart EL, Counoupas C, Steain M, Ashley C, Alca S, Hartley-Tassell L, von Itzstein M, Britton WJ, Petrovsky N, and Triccas JA
- Subjects
- Humans, Adjuvants, Vaccine metabolism, Cell Line, COVID-19 immunology, Dendritic Cells immunology, Dendritic Cells metabolism, Macrophages metabolism, Macrophages immunology, Mannans metabolism, Adjuvants, Immunologic pharmacology, Cell Adhesion Molecules metabolism, Inulin metabolism, Inulin analogs & derivatives, Lectins, C-Type metabolism, Receptors, Cell Surface metabolism
- Abstract
Delta inulin, or Advax, is a polysaccharide vaccine adjuvant that significantly enhances vaccine-mediated immune responses against multiple pathogens and was recently licensed for use in the coronavirus disease 2019 (COVID-19) vaccine SpikoGen. Although Advax has proven effective as an immune adjuvant, its specific binding targets have not been characterized. In this report, we identify a cellular receptor for Advax recognition. In vitro uptake of Advax particles by macrophage cell lines was substantially greater than that of latex beads of comparable size, suggesting an active uptake mechanism by phagocytic cells. Using a lectin array, Advax particles were recognized by lectins specific for various carbohydrate structures including mannosyl, N-acetylgalactosamine and galactose moieties. Expression in nonphagocytic cells of dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN), a C-type lectin receptor, resulted in enhanced uptake of fluorescent Advax particles compared with mock-transfected cells. Advax uptake was reduced with the addition of ethylenediaminetetraacetic acid and mannan to cells, which are known inhibitors of DC-SIGN function. Finally, a specific blockade of DC-SIGN using a neutralizing antibody abrogated Advax uptake in DC-SIGN-expressing cells. Together, these results identify DC-SIGN as a putative receptor for Advax. Given the known immunomodulatory role of DC-SIGN, the findings described here have implications for the use of Advax adjuvants in humans and inform future mechanistic studies., (© 2024 The Authors. Immunology & Cell Biology published by John Wiley & Sons Australia, Ltd on behalf of the Australian and New Zealand Society for Immunology, Inc.)
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- 2024
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16. Colony morphotype governs innate and adaptive pulmonary immune responses to Mycobacterium abscessus infection in C3HeB/FeJ mice.
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Ferrell KC, Stewart EL, Counoupas C, and Triccas JA
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- Animals, Mice, Disease Models, Animal, Macrophages immunology, Th1 Cells immunology, Mice, Inbred C3H, Female, Mycobacterium abscessus immunology, Mycobacterium Infections, Nontuberculous immunology, Lung immunology, Lung pathology, Lung microbiology, Adaptive Immunity, Immunity, Innate
- Abstract
Mycobacterium abscessus is an emerging pathogen that causes chronic pulmonary infection. Treatment is challenging owing in part to our incomplete understanding of M. abscessus virulence mechanisms that enable pathogen persistence, such as the differing pathogenicity of M. abscessus smooth (S) and rough (R) colony morphotype. While R M. abscessus is associated with chronic infection and worse patient outcomes, it is unknown how immune responses to S and R M. abscessus differ in an acute pulmonary infection setting. In this study, immunological outcomes of M. abscessus infection with S and R morphotypes were examined in an immune-competent C3HeB/FeJ murine model. R M. abscessus infection was associated with the rapid production of inflammatory chemokines and recruitment of activated, MHC-II
+ Ly6C+ macrophages to lungs and mediastinal LN (mLN). While both S and R M. abscessus increased T helper 1 (Th1) phenotype T cells in the lung, this was markedly delayed in mice infected with S M. abscessus. However, histopathological involvement and bacterial clearance were similar regardless of colony morphotype. These results demonstrate the importance of M. abscessus colony morphotype in shaping the development of pulmonary immune responses to M. abscessus, which further informs our understanding of M. abscessus host-pathogen interactions., (© 2024 The Authors. European Journal of Immunology published by Wiley‐VCH GmbH.)- Published
- 2024
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17. Lung IL-17A-Producing CD4 + T Cells Correlate with Protection after Intrapulmonary Vaccination with Differentially Adjuvanted Tuberculosis Vaccines.
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Stewart EL, Counoupas C, Quan DH, Wang T, Petrovsky N, Britton WJ, and Triccas JA
- Abstract
Tuberculosis (TB), caused by Mycobacterium tuberculosis , results in approximately 1.6 million deaths annually. BCG is the only TB vaccine currently in use and offers only variable protection; however, the development of more effective vaccines is hindered by a lack of defined correlates of protection (CoP) against M. tuberculosis . Pulmonary vaccine delivery is a promising strategy since it may promote lung-resident immune memory that can respond rapidly to respiratory infection. In this study, CysVac2, a subunit protein previously shown to be protective against M. tuberculosis in mouse models, was combined with either Advax
® adjuvant or a mixture of alum plus MPLA and administered intratracheally into mice. Peripheral immune responses were tracked longitudinally, and lung-local immune responses were measured after challenge. Both readouts were then correlated with protection after M. tuberculosis infection. Although considered essential for the control of mycobacteria, induction of IFN-γ-expressing CD4+ T cells in the blood or lungs did not correlate with protection. Instead, CD4+ T cells in the lungs expressing IL-17A correlated with reduced bacterial burden. This study identified pulmonary IL-17A-expressing CD4+ T cells as a CoP against M. tuberculosis and suggests that mucosal immune profiles should be explored for novel CoP.- Published
- 2024
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18. Mycobacterium tuberculosis Deficient in PdtaS Cytosolic Histidine Kinase Displays Attenuated Growth and Affords Protective Efficacy against Aerosol M. tuberculosis Infection in Mice.
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Prendergast KA, Nagalingam G, West NP, and Triccas JA
- Abstract
New control measures are urgently required to control tuberculosis (TB), as the current vaccine, Bacille Calmette-Guérin (BCG), has had a limited impact on disease spread. The identification of virulence mechanisms of Mycobacterium tuberculosis is an important strategy in vaccine design, as it permits the development of strains attenuated for growth that may have vaccine potential. In this report, we determined the role of the PdtaS response regulator in M. tuberculosis virulence and defined the vaccine potential of a pdtaS -deficient strain. Deletion of pdtaS ( Mtb
ΔpdtaS ) resulted in reduced persistence of M. tuberculosis within mouse organs, which was equivalent to the persistence of the BCG vaccine in the lung and liver of infected mice. However, the generation of effector CD4+ and CD8+ T cells (CD44+ CD62Llo KLRG1+ ) was similar between wild-type M. tuberculosis and MtbΔpdtaS and greater than that elicited by BCG. Heightened immunity induced by MtbΔpdtaS compared to BCG was also observed by analysis of antigen-specific IFN-γ-secreting T cell responses induced by vaccination. MtbΔpdtaS displayed improved protection against aerosol M. tuberculosis compared to BCG, which was most apparent in the lung at 20 weeks post-infection. These results suggest that the deletion of the PdtaS response regulator warrants further appraisal as a tool to combat TB in humans.- Published
- 2024
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19. CXCR3 Provides a Competitive Advantage for Retention of Mycobacterium tuberculosis -Specific Tissue-Resident Memory T Cells Following a Mucosal Tuberculosis Vaccine.
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Armitage E, Quan D, Flórido M, Palendira U, Triccas JA, and Britton WJ
- Abstract
Mycobacterium tuberculosis is a major human pathogen, and new vaccines are needed to prevent transmission. Mucosal vaccination may confer protection against M. tuberculosis by stimulating tissue-resident memory (T
RM ) CD4+ T cells in the lungs. The chemokine receptor CXCR3 promotes lung recruitment of T cells, but its role in TRM development is unknown. This study demonstrates the recombinant influenza A virus vaccine PR8.p25, expressing the immunodominant M. tuberculosis T cell epitope p25, induces CXCR3 expression on p25-specific CD4+ T cells in the lungs so that the majority of vaccine-induced CD4+ TRM expresses CXCR3 at 6 weeks. However, CXCR3-/- mice developed equivalent antigen-specific CD4+ T cell responses to wild-type (WT) mice following PR8.p25, and surprisingly retained more p25-specific CD4+ TRM in the lungs than WT mice at 6 weeks. The adoptive transfer of CXCR3-/- and WT P25 T cells into WT mice revealed that the initial recruitment of vaccine-induced CD4+ T cells into the lungs was independent of CXCR3, but by 6 weeks, CXCR3-deficient P25 T cells, and especially CXCR3-/- TRM , were significantly reduced compared to CXCR3-sufficient P25 T cells. Therefore, although CXCR3 was not essential for CD4+ TRM recruitment or retention, it provided a competitive advantage for the induction of M. tuberculosis -specific CD4+ TRM in the lungs following pulmonary immunization.- Published
- 2023
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20. A unique cytotoxic CD4 + T cell-signature defines critical COVID-19.
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Baird S, Ashley CL, Marsh-Wakefield F, Alca S, Ashhurst TM, Ferguson AL, Lukeman H, Counoupas C, Post JJ, Konecny P, Bartlett A, Martinello M, Bull RA, Lloyd A, Grey A, Hutchings O, Palendira U, Britton WJ, Steain M, and Triccas JA
- Abstract
Objectives: SARS-CoV-2 infection causes a spectrum of clinical disease presentation, ranging from asymptomatic to fatal. While neutralising antibody (NAb) responses correlate with protection against symptomatic and severe infection, the contribution of the T-cell response to disease resolution or progression is still unclear. As newly emerging variants of concern have the capacity to partially escape NAb responses, defining the contribution of individual T-cell subsets to disease outcome is imperative to inform the development of next-generation COVID-19 vaccines., Methods: Immunophenotyping of T-cell responses in unvaccinated individuals was performed, representing the full spectrum of COVID-19 clinical presentation. Computational and manual analyses were used to identify T-cell populations associated with distinct disease states., Results: Critical SARS-CoV-2 infection was characterised by an increase in activated and cytotoxic CD4
+ lymphocytes (CTL). These CD4+ CTLs were largely absent in asymptomatic to severe disease states. In contrast, non-critical COVID-19 was associated with high frequencies of naïve T cells and lack of activation marker expression., Conclusion: Highly activated and cytotoxic CD4+ T-cell responses may contribute to cell-mediated host tissue damage and progression of COVID-19. Induction of these potentially detrimental T-cell responses should be considered when developing and implementing effective COVID-19 control strategies., Competing Interests: The authors declare no conflict of interest., (© 2023 The Authors. Clinical & Translational Immunology published by John Wiley & Sons Australia, Ltd on behalf of Australian and New Zealand Society for Immunology, Inc.)- Published
- 2023
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21. Clinical and Experimental Determination of Protection Afforded by BCG Vaccination against Infection with Non-Tuberculous Mycobacteria: A Role in Cystic Fibrosis?
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Warner S, Blaxland A, Counoupas C, Verstraete J, Zampoli M, Marais BJ, Fitzgerald DA, Robinson PD, and Triccas JA
- Abstract
Mycobacterium abscessus is a nontuberculous mycobacterium (NTM) of particular concern in individuals with obstructive lung diseases such as cystic fibrosis (CF). Treatment requires multiple drugs and is characterised by high rates of relapse; thus, new strategies to limit infection are urgently required. This study sought to determine how Bacille Calmette-Guérin (BCG) vaccination may impact NTM infection, using a murine model of Mycobacterium abscessus infection and observational data from a non-BCG vaccinated CF cohort in Sydney, Australia and a BCG-vaccinated CF cohort in Cape Town, South Africa. In mice, BCG vaccination induced multifunctional antigen-specific CD4
+ T cells circulating in the blood and was protective against dissemination of bacteria to the spleen. Prior infection with M. abscessus afforded the highest level of protection against M. abscessus challenge in the lung, and immunity was characterised by a greater frequency of pulmonary cytokine-secreting CD4+ T cells compared to BCG vaccination. In the clinical CF cohorts, the overall rates of NTM sampling during a three-year period were equivalent; however, rates of NTM colonisation were significantly lower in the BCG-vaccinated (Cape Town) cohort, which was most apparent for M. abscessus . This study provides evidence that routine BCG vaccination may reduce M. abscessus colonisation in individuals with CF, which correlates with the ability of BCG to induce multifunctional CD4+ T cells recognising M. abscessus in a murine model. Further research is needed to determine the optimal strategies for limiting NTM infections in individuals with CF.- Published
- 2023
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22. L-selectin-dependent and -independent homing of naïve lymphocytes through the lung draining lymph node support T cell response to pulmonary Mycobacterium tuberculosis infection.
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Daniel L, Counoupas C, Bhattacharyya ND, Triccas JA, Britton WJ, and Feng CG
- Subjects
- Mice, Animals, L-Selectin metabolism, T-Lymphocytes, Vascular Endothelial Growth Factor A metabolism, Lymphocytes, Lung, Lymph Nodes, Tuberculosis, Pulmonary, Tuberculosis metabolism, Mycobacterium tuberculosis
- Abstract
Recruiting large numbers of naïve lymphocytes to lymph nodes is critical for mounting an effective adaptive immune response. While most naïve lymphocytes utilize homing molecule L-selectin to enter lymph nodes, some circulating cells can traffic to the lung-draining mediastinal lymph node (mLN) through lymphatics via the intermediate organ, lung. However, whether this alternative trafficking mechanism operates in infection and contributes to T cell priming are unknown. We report that in pulmonary Mycobacterium tuberculosis-infected mice, homing of circulating lymphocytes to the mLN is significantly less efficient than to non-draining lymph node. CD62L blockade only partially reduced the homing of naïve T lymphocytes, consistent with L-selectin-independent routing of naïve lymphocytes to the site. We further demonstrated that lymphatic vessels in infected mLN expanded significantly and inhibiting lymphangiogenesis with a vascular endothelial growth factor receptor 3 kinase inhibitor reduced the recruitment of intravenously injected naïve lymphocytes to the mLN. Finally, mycobacterium-specific T cells entering via the L-selectin-independent route were readily activated in the mLN. Our study suggests that both L-selectin-dependent and -independent pathways contribute to naïve lymphocyte entry into mLN during M. tuberculosis infection and the latter pathway may represent an important mechanism for orchestrating host defence in the lungs., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Daniel et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
- Published
- 2023
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23. Neutrophil Conversion to a Tumor-Killing Phenotype Underpins Effective Microbial Therapy.
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Yam AO, Bailey J, Lin F, Jakovija A, Youlten SE, Counoupas C, Gunzer M, Bald T, Woodruff TM, Triccas JA, Goldstein LD, Gallego-Ortega D, Grey ST, and Chtanova T
- Subjects
- Mice, Animals, CD8-Positive T-Lymphocytes, Inflammation pathology, Phenotype, Neutrophil Infiltration, Tumor Microenvironment, Neutrophils metabolism, Neoplasms genetics, Neoplasms therapy, Neoplasms metabolism
- Abstract
The inflammatory microenvironment of solid tumors creates a protumorigenic milieu that resembles chronic inflammation akin to a subverted wound healing response. Here, we investigated the effect of converting the tumor microenvironment from a chronically inflamed state to one of acute microbial inflammation by injecting microbial bioparticles directly into tumors. Intratumoral microbial bioparticle injection led to rapid and dramatic changes in the tumor immune composition, the most striking of which was a substantial increase in the presence of activated neutrophils. In situ photoconversion and intravital microscopy indicated that tumor neutrophils transiently switched from sessile producers of VEGF to highly motile neutrophils that clustered to make neutrophil-rich domains in the tumor. The neutrophil clusters remodeled tumor tissue and repressed tumor growth. Single-cell transcriptional analysis of microbe-stimulated neutrophils showed a profound shift in gene expression towards heightened activation and antimicrobial effector function. Microbe-activated neutrophils also upregulated chemokines known to regulate neutrophil and CD8+ T-cell recruitment. Microbial therapy also boosted CD8+ T-cell function and enhanced the therapeutic benefit of checkpoint inhibitor therapy in tumor-bearing mice and provided protection in a model of tumor recurrence. These data indicate that one of the major effector mechanisms of microbial therapy is the conversion of tumor neutrophils from a wound healing to an acutely activated cytotoxic phenotype, highlighting a rationale for broader deployment of microbial therapy in the treatment of solid cancers., Significance: Intratumoral injection of microbial bioparticles stimulates neutrophil antitumor functions, suggesting pathways for optimizing efficacy of microbial therapies and paving the way for their broader utilization in the clinic., (©2023 The Authors; Published by the American Association for Cancer Research.)
- Published
- 2023
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24. Correlates of Protection, Thresholds of Protection, and Immunobridging among Persons with SARS-CoV-2 Infection.
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Khoury DS, Schlub TE, Cromer D, Steain M, Fong Y, Gilbert PB, Subbarao K, Triccas JA, Kent SJ, and Davenport MP
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- Humans, SARS-CoV-2, Pandemics prevention & control, Antibodies, Neutralizing, COVID-19 Vaccines, Antibodies, Viral, Spike Glycoprotein, Coronavirus, COVID-19
- Abstract
Several studies have shown that neutralizing antibody levels correlate with immune protection from COVID-19 and have estimated the relationship between neutralizing antibodies and protection. However, results of these studies vary in terms of estimates of the level of neutralizing antibodies required for protection. By normalizing antibody titers, we found that study results converge on a consistent relationship between antibody levels and protection from COVID-19. This finding can be useful for planning future vaccine use, determining population immunity, and reducing the global effects of the COVID-19 pandemic.
- Published
- 2023
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25. Discovery of Anti-tubercular Analogues of Bedaquiline with Modified A-, B- and C-Ring Subunits.
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Barbaro L, Nagalingam G, Triccas JA, Tan L, West NP, Priebbenow DL, and Baell JB
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- Humans, Diarylquinolines pharmacology, Diarylquinolines chemistry, Antitubercular Agents pharmacology, Antitubercular Agents chemistry, Mycobacterium tuberculosis, Tuberculosis, Multidrug-Resistant
- Abstract
To date, the clinical use of the anti-tubercular therapy bedaquiline has been somewhat limited due to safety concerns. Recent investigations determined that modification of the B- and C-ring units of bedaquiline delivered new diarylquinolines (for example TBAJ-587) with potent anti-tubercular activity yet an improved safety profile due to reduced affinity for the hERG channel. Building on our recent discovery that substitution of the quinoline motif (the A-ring subunit) for C5-aryl pyridine groups within bedaquiline analogues led to retention of anti-tubercular activity, we investigated the concurrent modification of A-, B- and C-ring units within bedaquiline variants. This led to the discovery that 4-trifluoromethoxyphenyl and 4-chlorophenyl pyridyl analogues of TBAJ-587 retained relatively potent anti-tubercular activity and for the 4-chlorophenyl derivative in particular, a significant reduction in hERG inhibition relative to bedaquiline was achieved, demonstrating that modifications of the A-, B- and C-ring units within the bedaquiline structure is a viable strategy for the design of effective, yet safer (and less lipophilic) anti-tubercular compounds., (© 2022 Wiley-VCH GmbH.)
- Published
- 2023
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26. Mucosal TLR2-activating protein-based vaccination induces potent pulmonary immunity and protection against SARS-CoV-2 in mice.
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Ashhurst AS, Johansen MD, Maxwell JWC, Stockdale S, Ashley CL, Aggarwal A, Siddiquee R, Miemczyk S, Nguyen DH, Mackay JP, Counoupas C, Byrne SN, Turville S, Steain M, Triccas JA, Hansbro PM, Payne RJ, and Britton WJ
- Subjects
- Mice, Humans, Animals, SARS-CoV-2, Toll-Like Receptor 2, COVID-19 Vaccines, Spike Glycoprotein, Coronavirus, Vaccination, Lung, Antibodies, Viral, Immunity, Mucosal, Antibodies, Neutralizing, Viral Vaccines, COVID-19 prevention & control
- Abstract
Current vaccines against SARS-CoV-2 substantially reduce mortality, but protection against infection is less effective. Enhancing immunity in the respiratory tract, via mucosal vaccination, may provide protection against infection and minimise viral spread. Here, we report testing of a subunit vaccine in mice, consisting of SARS-CoV-2 Spike protein with a TLR2-stimulating adjuvant (Pam
2 Cys), delivered to mice parenterally or mucosally. Both routes of vaccination induce substantial neutralising antibody (nAb) titres, however, mucosal vaccination uniquely generates anti-Spike IgA, increases nAb in the serum and airways, and increases lung CD4+ T-cell responses. TLR2 is expressed by respiratory epithelia and immune cells. Using TLR2 deficient chimeric mice, we determine that TLR2 expression in either compartment facilitates early innate responses to mucosal vaccination. By contrast, TLR2 on hematopoietic cells is essential for optimal lung-localised, antigen-specific responses. In K18-hACE2 mice, vaccination provides complete protection against disease and sterilising lung immunity against SARS-CoV-2, with a short-term non-specific protective effect from mucosal Pam2 Cys alone. These data support mucosal vaccination as a strategy to improve protection in the respiratory tract against SARS-CoV-2 and other respiratory viruses., (© 2022. The Author(s).)- Published
- 2022
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27. Stromal structure remodeling by B lymphocytes limits T cell activation in lymph nodes of Mycobacterium tuberculosis-infected mice.
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Daniel L, Bhattacharyya ND, Counoupas C, Cai Y, Chen X, Triccas JA, Britton WJ, and Feng CG
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- Animals, Mice, Mice, Inbred C57BL, Lymph Nodes, T-Lymphocytes, B-Lymphocytes, Inflammation, Mycobacterium tuberculosis, Tuberculosis
- Abstract
An effective adaptive immune response depends on the organized architecture of secondary lymphoid organs, including the lymph nodes (LNs). While the cellular composition and microanatomy of LNs under steady state are well defined, the impact of chronic tissue inflammation on the structure and function of draining LNs is incompletely understood. Here we showed that Mycobacterium tuberculosis infection remodeled LN architecture by increasing the number and paracortical translocation of B cells. The formation of paracortical B lymphocyte and CD35+ follicular dendritic cell clusters dispersed CCL21-producing fibroblastic reticular cells and segregated pathogen-containing myeloid cells from antigen-specific CD4+ T cells. Depletion of B cells restored the chemokine and lymphoid structure and reduced bacterial burdens in LNs of the chronically infected mice. Importantly, this remodeling process impaired activation of naive CD4+ T cells in response to mycobacterial and unrelated antigens during chronic tuberculosis infection. Our studies reveal a mechanism in the regulation of LN microanatomy during inflammation and identify B cells as a critical element limiting the T cell response to persistent intracellular infection in LNs.
- Published
- 2022
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28. Relating In Vitro Neutralization Level and Protection in the CVnCoV (CUREVAC) Trial.
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Cromer D, Reynaldi A, Steain M, Triccas JA, Davenport MP, and Khoury DS
- Subjects
- Antibodies, Neutralizing, Antibodies, Viral, COVID-19 Vaccines, Humans, SARS-CoV-2, COVID-19 prevention & control, Viral Vaccines
- Abstract
The vaccine candidate CVnCoV (CUREVAC) showed surprisingly low efficacy in a recent phase 3 trial compared with other messenger RNA (mRNA) vaccines. Here we show that the low efficacy follows from the dose used and the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants and is predicted by the neutralizing antibody response induced by the vaccine., (© The Author(s) 2022. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)
- Published
- 2022
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29. Affordable SARS-CoV-2 protein vaccines for the pandemic endgame.
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Triccas JA, Kint J, and Wurm FM
- Published
- 2022
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30. Carborane clusters increase the potency of bis-substituted cyclam derivatives against Mycobacterium tuberculosis .
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Smith N, Quan D, Nagalingam G, Triccas JA, Rendina LM, and Rutledge PJ
- Abstract
Bis-substituted cyclam derivatives have recently emerged as a promising new class of antibacterial agents, displaying excellent activity against drug-resistant Mycobacterium tuberculosis ( Mtb ) and in vivo efficacy in a zebrafish assay. Herein we report the synthesis and biological activity of new carborane derivatives within this class of antitubercular compounds. The resulting carborane-cyclam conjugates incorporating either hydrophobic closo -1,2-carborane or anionic, hydrophilic nido -7,8-carborane clusters display promising activity in an antibacterial assay employing the virulent Mtb strain H37Rv. The most active of these carborane derivatives exhibit MIC
50 values of <1 μM, making them the most active compounds in this unique class of antibacterial cyclams reported to date., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)- Published
- 2022
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31. Characterization of the Protective Immune Responses Conferred by Recombinant BCG Overexpressing Components of Mycobacterium tuberculosis Sec Protein Export System.
- Author
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Nisa A, Counoupas C, Pinto R, Britton WJ, and Triccas JA
- Abstract
Mycobacterium bovis Bacillus Calmette-Guérin (BCG) is the only approved vaccine against tuberculosis (TB). However, its efficacy in preventing pulmonary TB in adults is limited. Despite its variable efficacy, BCG offers a number of unique and beneficial characteristics, which make it suitable as a vaccine vehicle to express recombinant molecules. In Mycobacterium tuberculosis , the general Sec pathway is an essential cellular process, and it is responsible for exporting the majority of proteins across the cytoplasmic membrane, including potent immune-protective antigens, such as members of the antigen 85 (Ag85) complex. We engineered BCG to overexpress the M. tuberculosis SecDFG proteins in order to improve the efficiency of the Sec-dependent export system and, thus, enhance the secretion of immunogenic proteins. BCG
SecDFG displayed increased intracellular survival within macrophages in vitro and greater persistence in the lymphoid organs of vaccinated mice than parental BCG. In addition, vaccination with BCGSecDFG generated higher numbers of IFN-γ-secreting T cells in response to secreted mycobacterial antigens compared to BCG, particularly members of the Ag85 complex. Furthermore, vaccination with BCGSecDFG significantly reduced the bacterial load in the lungs and spleens of M. tuberculosis -infected mice, which was comparable to the protection afforded by parental BCG. Therefore, the modification of protein secretion in BCG can improve antigen-specific immunogenicity.- Published
- 2022
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32. New standards for precision medicine in TB management.
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Triccas JA and McLachlan AJ
- Subjects
- Humans, Reference Standards, Precision Medicine, Tuberculosis therapy
- Published
- 2022
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33. Mucosal immunization with a delta-inulin adjuvanted recombinant spike vaccine elicits lung-resident immune memory and protects mice against SARS-CoV-2.
- Author
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Stewart EL, Counoupas C, Johansen MD, Nguyen DH, Miemczyk S, Hansbro NG, Ferrell KC, Ashhurst A, Alca S, Ashley C, Steain M, Britton WJ, Hansbro PM, Petrovsky N, and Triccas JA
- Subjects
- Mice, Animals, Humans, Inulin, COVID-19 Vaccines, CD8-Positive T-Lymphocytes, Immunologic Memory, Pandemics, Immunization, Vaccines, Synthetic, Vaccination, Adjuvants, Immunologic, Gastric Mucosa, Lung, SARS-CoV-2, COVID-19 prevention & control
- Abstract
Multiple SARS-CoV-2 vaccine candidates have been approved for use and have had a major impact on the COVID-19 pandemic. There remains, however, a significant need for vaccines that are safe, easily transportable and protective against infection, as well as disease. Mucosal vaccination is favored for its ability to induce immune memory at the site of infection, making it appealing for SARS-CoV-2 vaccine strategies. In this study we performed in-depth analysis of the immune responses in mice to a subunit recombinant spike protein vaccine formulated with the delta-inulin adjuvant Advax when administered intratracheally (IT), versus intramuscular delivery (IM). Both routes produced robust neutralizing antibody titers (NAb) and generated sterilizing immunity against SARS-CoV-2. IT delivery, however, produced significantly higher systemic and lung-local NAb that resisted waning up to six months post vaccination, and only IT delivery generated inducible bronchus-associated lymphoid tissue (iBALT), a site of lymphocyte antigen presentation and proliferation. This was coupled with robust and long-lasting lung tissue-resident memory CD4
+ and CD8+ T cells that were not observed in IM-vaccinated mice. This study provides a detailed view of the lung-resident cellular response to IT vaccination against SARS-CoV-2 and demonstrates the importance of delivery site selection in the development of vaccine candidates., (© 2022. The Author(s).)- Published
- 2022
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34. Correction: Stewart et al. Adjuvant Strategies for More Effective Tuberculosis Vaccine Immunity. Microorganisms 2019, 7 , 255.
- Author
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Stewart E, Triccas JA, and Petrovsky N
- Abstract
The authors wish to make the following corrections to this paper [...].
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- 2022
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35. Virulence Mechanisms of Mycobacterium abscessus : Current Knowledge and Implications for Vaccine Design.
- Author
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Ferrell KC, Johansen MD, Triccas JA, and Counoupas C
- Abstract
Mycobacterium abscessus is a member of the non-tuberculous mycobacteria (NTM) group, responsible for chronic infections in individuals with cystic fibrosis (CF) or those otherwise immunocompromised. While viewed traditionally as an opportunistic pathogen, increasing research into M. abscessus in recent years has highlighted its continued evolution into a true pathogen. This is demonstrated through an extensive collection of virulence factors (VFs) possessed by this organism which facilitate survival within the host, particularly in the harsh environment of the CF lung. These include VFs resembling those of other Mycobacteria, and non-mycobacterial VFs, both of which make a notable contribution in shaping M. abscessus interaction with the host. Mycobacterium abscessus continued acquisition of VFs is cause for concern and highlights the need for novel vaccination strategies to combat this pathogen. An effective M. abscessus vaccine must be suitably designed for target populations (i.e., individuals with CF) and incorporate current knowledge on immune correlates of protection against M. abscessus infection. Vaccination strategies must also build upon lessons learned from ongoing efforts to develop novel vaccines for other pathogens, particularly Mycobacterium tuberculosis ( M. tb ); decades of research into M. tb has provided insight into unconventional and innovative vaccine approaches that may be applied to M. abscessus . Continued research into M. abscessus pathogenesis will be critical for the future development of safe and effective vaccines and therapeutics to reduce global incidence of this emerging pathogen., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Ferrell, Johansen, Triccas and Counoupas.)
- Published
- 2022
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36. High-Titer Neutralizing Antibodies against the SARS-CoV-2 Delta Variant Induced by Alhydroxyquim-II-Adjuvanted Trimeric Spike Antigens.
- Author
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Counoupas C, Pino P, Stella AO, Ashley C, Lukeman H, Bhattacharyya ND, Tada T, Anchisi S, Metayer C, Martinis J, Aggarwal A, Dcosta BM, Britton WJ, Kint J, Wurm MJ, Landau NR, Steain M, Turville SG, Wurm FM, David SA, and Triccas JA
- Subjects
- Animals, Antibodies, Neutralizing blood, Antibodies, Viral blood, CD4-Positive T-Lymphocytes immunology, Horses, Mice, Rabbits, T-Lymphocytes immunology, Antibodies, Neutralizing biosynthesis, Antibodies, Viral biosynthesis, COVID-19 Vaccines immunology, SARS-CoV-2 immunology
- Abstract
Global control of COVID-19 will require the deployment of vaccines capable of inducing long-term protective immunity against SARS-CoV-2 variants. In this report, we describe an adjuvanted subunit candidate vaccine that affords elevated, sustained, and cross-variant SARS-CoV-2 neutralizing antibodies (NAbs) in multiple animal models. Alhydroxiquim-II is a Toll-Like Receptor (TLR) 7/8 small-molecule agonist chemisorbed on aluminum hydroxide (Alhydrogel). Vaccination with Alhydroxiquim-II combined with a stabilized, trimeric form of the SARS-CoV-2 spike protein (termed CoVac-II) resulted in high-titer NAbs in mice, with no decay in responses over an 8-month period. NAbs from sera of CoVac-II-immunized mice, horses and rabbits were broadly neutralizing against SARS-CoV-2 variants. Boosting long-term CoVac-II-immunized mice with adjuvanted spike protein from the Beta variant markedly increased levels of NAb titers against multiple SARS-CoV-2 variants; notably, high titers against the Delta variant were observed. These data strongly support the clinical assessment of Alhydroxiquim-II-adjuvanted spike proteins to protect against SARS-CoV-2 variants of concern. IMPORTANCE There is an urgent need for next-generation COVID-19 vaccines that are safe, demonstrate high protective efficacy against SARS-CoV-2 variants and can be manufactured at scale. We describe a vaccine candidate (CoVac-II) that is based on stabilized, trimeric spike antigen produced in an optimized, scalable and chemically defined production process. CoVac-II demonstrates strong and persistent immunity after vaccination of mice, and is highly immunogenic in multiple animal models, including rabbits and horses. We further show that prior immunity can be boosted using a recombinant spike antigen from the Beta variant; importantly, plasma from boosted mice effectively neutralize multiple SARS-CoV-2 variants in vitro , including Delta. The strong humoral and Th1-biased immunogenicity of CoVac-II is driven by use of Alhydroxiquim-II (AHQ-II), the first adjuvant in an authorized vaccine that acts through the dual Toll-like receptor (TLR)7 and TLR8 pathways, as part of the Covaxin vaccine. Our data suggest AHQ-II/spike protein combinations could constitute safe, affordable, and mass-manufacturable COVID-19 vaccines for global distribution.
- Published
- 2022
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37. Rough and smooth variants of Mycobacterium abscessus are differentially controlled by host immunity during chronic infection of adult zebrafish.
- Author
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Kam JY, Hortle E, Krogman E, Warner SE, Wright K, Luo K, Cheng T, Manuneedhi Cholan P, Kikuchi K, Triccas JA, Britton WJ, Johansen MD, Kremer L, and Oehlers SH
- Subjects
- Animals, Animals, Genetically Modified, Bacterial Proteins genetics, Bacterial Proteins metabolism, Disease Models, Animal, Gene Knockdown Techniques, Granuloma microbiology, Granuloma pathology, Host-Pathogen Interactions immunology, Humans, Immunity, Innate, Lymphocyte Activation, Mycobacterium Infections, Nontuberculous microbiology, Mycobacterium Infections, Nontuberculous pathology, Mycobacterium abscessus genetics, Mycobacterium abscessus immunology, Persistent Infection microbiology, Persistent Infection pathology, Signal Transduction immunology, T-Lymphocytes, Regulatory immunology, Tumor Necrosis Factor-alpha metabolism, Zebrafish, Zebrafish Proteins metabolism, Granuloma immunology, Mycobacterium Infections, Nontuberculous immunology, Mycobacterium abscessus pathogenicity, Persistent Infection immunology
- Abstract
Prevalence of Mycobacterium abscessus infections is increasing in patients with respiratory comorbidities. After initial colonisation, M. abscessus smooth colony (S) variants can undergo an irreversible genetic switch into highly inflammatory, rough colony (R) variants, often associated with a decline in pulmonary function. Here, we use an adult zebrafish model of chronic infection with R and S variants to study M. abscessus pathogenesis in the context of fully functioning host immunity. We show that infection with an R variant causes an inflammatory immune response that drives necrotic granuloma formation through host TNF signalling, mediated by the tnfa, tnfr1 and tnfr2 gene products. T cell-dependent immunity is stronger against the R variant early in infection, and regulatory T cells associate with R variant granulomas and limit bacterial growth. In comparison, an S variant proliferates to high burdens but appears to be controlled by TNF-dependent innate immunity early during infection, resulting in delayed granuloma formation. Thus, our work demonstrates the applicability of adult zebrafish to model persistent M. abscessus infection, and illustrates differences in the immunopathogenesis induced by R and S variants during granulomatous infection., (© 2022. The Author(s).)
- Published
- 2022
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38. Neutralising antibody titres as predictors of protection against SARS-CoV-2 variants and the impact of boosting: a meta-analysis.
- Author
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Cromer D, Steain M, Reynaldi A, Schlub TE, Wheatley AK, Juno JA, Kent SJ, Triccas JA, Khoury DS, and Davenport MP
- Subjects
- Antibodies, Neutralizing, Antibodies, Viral, COVID-19 Vaccines, Humans, COVID-19 epidemiology, SARS-CoV-2 genetics
- Abstract
Background: Several SARS-CoV-2 variants of concern have been identified that partly escape serum neutralisation elicited by current vaccines. Studies have also shown that vaccines demonstrate reduced protection against symptomatic infection with SARS-CoV-2 variants. We explored whether in-vitro neutralisation titres remain predictive of vaccine protection from infection with SARS-CoV-2 variants., Methods: In this meta-analysis, we analysed published data from 24 identified studies on in-vitro neutralisation and clinical protection to understand the loss of neutralisation to existing SARS-CoV-2 variants of concern. We integrated the results of this analysis into our existing statistical model relating in-vitro neutralisation to protection (parameterised on data from ancestral virus infection) to estimate vaccine efficacy against SARS-CoV-2 variants. We also analysed data on boosting of vaccine responses and use the model to predict the impact of booster vaccination on protection against SARS-CoV-2 variants., Findings: The neutralising activity against the ancestral SARS-CoV-2 was highly predictive of neutralisation of variants of concern. Decreases in neutralisation titre to the alpha (1·6-fold), beta (8·8-fold), gamma (3·5-fold), and delta (3·9-fold) variants (compared to the ancestral virus) were not significantly different between different vaccines. Neutralisation remained strongly correlated with protection from symptomatic infection with SARS-CoV-2 variants of concern ( r
S =0·81, p=0·0005) and the existing model remained predictive of vaccine efficacy against variants of concern once decreases in neutralisation to the variants of concern were incorporated. Modelling of predicted vaccine efficacy against variants over time suggested that protection against symptomatic infection might decrease below 50% within the first year after vaccination for some vaccines. Boosting of previously infected individuals with existing vaccines (which target ancestral virus) is predicted to provide a higher degree of protection from infection with variants of concern than primary vaccination schedules alone., Interpretation: In-vitro neutralisation titres remain a correlate of protection from SARS-CoV-2 variants and modelling of the effects of waning immunity predicts a loss of protection to the variants after vaccination. However, booster vaccination with current vaccines should enable higher neutralisation to SARS-CoV-2 variants than is achieved with primary vaccination, which is predicted to provide robust protection from severe infection outcomes with the current SARS-CoV-2 variants of concern, at least in the medium term., Funding: The National Health and Medical Research Council (Australia), the Medical Research Future Fund (Australia), and the Victorian Government., Competing Interests: DSK is elected executive committee member of the New South Wales branch of the Australian and New Zealand Industrial and Applied Mathematics society. MPD is senior editor for eLife, for which he receives an annual retainer. All other authors declare no competing interests., (© 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.)- Published
- 2022
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39. A single dose, BCG-adjuvanted COVID-19 vaccine provides sterilising immunity against SARS-CoV-2 infection.
- Author
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Counoupas C, Johansen MD, Stella AO, Nguyen DH, Ferguson AL, Aggarwal A, Bhattacharyya ND, Grey A, Hutchings O, Patel K, Siddiquee R, Stewart EL, Feng CG, Hansbro NG, Palendira U, Steain MC, Saunders BM, Low JKK, Mackay JP, Kelleher AD, Britton WJ, Turville SG, Hansbro PM, and Triccas JA
- Abstract
Global control of COVID-19 requires broadly accessible vaccines that are effective against SARS-CoV-2 variants. In this report, we exploit the immunostimulatory properties of bacille Calmette-Guérin (BCG), the existing tuberculosis vaccine, to deliver a vaccination regimen with potent SARS-CoV-2-specific protective immunity. Combination of BCG with a stabilised, trimeric form of SARS-CoV-2 spike antigen promoted rapid development of virus-specific IgG antibodies in the blood of vaccinated mice, that was further augmented by the addition of alum. This vaccine formulation, BCG:CoVac, induced high-titre SARS-CoV-2 neutralising antibodies (NAbs) and Th1-biased cytokine release by vaccine-specific T cells, which correlated with the early emergence of T follicular helper cells in local lymph nodes and heightened levels of antigen-specific plasma B cells after vaccination. Vaccination of K18-hACE2 mice with a single dose of BCG:CoVac almost completely abrogated disease after SARS-CoV-2 challenge, with minimal inflammation and no detectable virus in the lungs of infected animals. Boosting BCG:CoVac-primed mice with a heterologous vaccine further increased SARS-CoV-2-specific antibody responses, which effectively neutralised B.1.1.7 and B.1.351 SARS-CoV-2 variants of concern. These findings demonstrate the potential for BCG-based vaccination to protect against major SARS-CoV-2 variants circulating globally., (© 2021. The Author(s).)
- Published
- 2021
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40. Boosting BCG with recombinant influenza A virus tuberculosis vaccines increases pulmonary T cell responses but not protection against Mycobacterium tuberculosis infection.
- Author
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Muflihah H, Flórido M, Lin LCW, Xia Y, Triccas JA, Stambas J, and Britton WJ
- Subjects
- Animals, Epitopes, Epitopes, T-Lymphocyte genetics, Epitopes, T-Lymphocyte immunology, Female, Immunization, Secondary, Immunogenicity, Vaccine, Lung immunology, Memory T Cells immunology, Mice, Mice, Inbred C57BL, Tuberculosis, Pulmonary immunology, Vaccines, Synthetic immunology, BCG Vaccine immunology, Influenza A virus immunology, Mycobacterium tuberculosis immunology, T-Lymphocytes immunology, Tuberculosis, Pulmonary prevention & control
- Abstract
The current Mycobacterium bovis BCG vaccine provides inconsistent protection against pulmonary infection with Mycobacterium tuberculosis. Immunity induced by subcutaneous immunization with BCG wanes and does not promote early recruitment of T cell to the lungs after M. tuberculosis infection. Delivery of Tuberculosis (TB) vaccines to the lungs may increase and prolong immunity at the primary site of M. tuberculosis infection. Pulmonary immunization with recombinant influenza A viruses (rIAVs) expressing an immune-dominant M. tuberculosis CD4+ T cell epitope (PR8-p25 and X31-p25) stimulates protective immunity against lung TB infection. Here, we investigated the potential use of rIAVs to improve the efficacy of BCG using simultaneous immunization (SIM) and prime-boost strategies. SIM with parenteral BCG and intranasal PR8-p25 resulted in equivalent protection to BCG alone against early, acute and chronic M. tuberculosis infection. Boosting BCG with rIAVs increased the frequency of IFN-γ-secreting specific T cells (p<0.001) and polyfunctional CD4+ T cells (p<0.05) in the lungs compared to the BCG alone, however, this did not result in a significant increase in protection against M. tuberculosis compared to BCG alone. Therefore, sequential pulmonary immunization with these rIAVs after BCG increased M. tuberculosis-specific memory T cell responses in the lung, but not protection against M. tuberculosis infection., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2021
- Full Text
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41. Advancing Adjuvants for Mycobacterium tuberculosis Therapeutics.
- Author
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Enriquez AB, Izzo A, Miller SM, Stewart EL, Mahon RN, Frank DJ, Evans JT, Rengarajan J, and Triccas JA
- Subjects
- Animals, Congresses as Topic, Disease Models, Animal, Humans, Immune Evasion, Immunity, National Institute of Allergy and Infectious Diseases (U.S.), Tuberculosis therapy, United States, Adjuvants, Immunologic therapeutic use, Mycobacterium tuberculosis physiology, Tuberculosis immunology, Tuberculosis Vaccines immunology
- Abstract
Tuberculosis (TB) remains one of the leading causes of death worldwide due to a single infectious disease agent. BCG, the only licensed vaccine against TB, offers limited protection against pulmonary disease in children and adults. TB vaccine research has recently been reinvigorated by new data suggesting alternative administration of BCG induces protection and a subunit/adjuvant vaccine that provides close to 50% protection. These results demonstrate the need for generating adjuvants in order to develop the next generation of TB vaccines. However, development of TB-targeted adjuvants is lacking. To help meet this need, NIAID convened a workshop in 2020 titled "Advancing Vaccine Adjuvants for Mycobacterium tuberculosis Therapeutics". In this review, we present the four areas identified in the workshop as necessary for advancing TB adjuvants: 1) correlates of protective immunity, 2) targeting specific immune cells, 3) immune evasion mechanisms, and 4) animal models. We will discuss each of these four areas in detail and summarize what is known and what we can advance on in order to help develop more efficacious TB vaccines., Competing Interests: Author RNM was employed by company Columbus Technologies & Services Inc. JE and SM are employees of and own shares in Inimmune Corporation. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Enriquez, Izzo, Miller, Stewart, Mahon, Frank, Evans, Rengarajan and Triccas.)
- Published
- 2021
- Full Text
- View/download PDF
42. Neutralizing antibody levels are highly predictive of immune protection from symptomatic SARS-CoV-2 infection.
- Author
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Khoury DS, Cromer D, Reynaldi A, Schlub TE, Wheatley AK, Juno JA, Subbarao K, Kent SJ, Triccas JA, and Davenport MP
- Subjects
- COVID-19 immunology, Humans, Logistic Models, Severity of Illness Index, Antibodies, Neutralizing immunology, Antibodies, Viral immunology, COVID-19 prevention & control, COVID-19 Vaccines therapeutic use, SARS-CoV-2 immunology
- Abstract
Predictive models of immune protection from COVID-19 are urgently needed to identify correlates of protection to assist in the future deployment of vaccines. To address this, we analyzed the relationship between in vitro neutralization levels and the observed protection from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection using data from seven current vaccines and from convalescent cohorts. We estimated the neutralization level for 50% protection against detectable SARS-CoV-2 infection to be 20.2% of the mean convalescent level (95% confidence interval (CI) = 14.4-28.4%). The estimated neutralization level required for 50% protection from severe infection was significantly lower (3% of the mean convalescent level; 95% CI = 0.7-13%, P = 0.0004). Modeling of the decay of the neutralization titer over the first 250 d after immunization predicts that a significant loss in protection from SARS-CoV-2 infection will occur, although protection from severe disease should be largely retained. Neutralization titers against some SARS-CoV-2 variants of concern are reduced compared with the vaccine strain, and our model predicts the relationship between neutralization and efficacy against viral variants. Here, we show that neutralization level is highly predictive of immune protection, and provide an evidence-based model of SARS-CoV-2 immune protection that will assist in developing vaccine strategies to control the future trajectory of the pandemic., (© 2021. The Author(s), under exclusive licence to Springer Nature America, Inc.)
- Published
- 2021
- Full Text
- View/download PDF
43. Discovery of Cyclic Peptide Ligands to the SARS-CoV-2 Spike Protein Using mRNA Display.
- Author
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Norman A, Franck C, Christie M, Hawkins PME, Patel K, Ashhurst AS, Aggarwal A, Low JKK, Siddiquee R, Ashley CL, Steain M, Triccas JA, Turville S, Mackay JP, Passioura T, and Payne RJ
- Abstract
The COVID-19 pandemic, caused by SARS-CoV-2, has led to substantial morbidity, mortality, and disruption globally. Cellular entry of SARS-CoV-2 is mediated by the viral spike protein, and affinity ligands to this surface protein have the potential for applications as antivirals and diagnostic reagents. Here, we describe the affinity selection of cyclic peptide ligands to the SARS-CoV-2 spike protein receptor binding domain (RBD) from three distinct libraries (in excess of a trillion molecules each) by mRNA display. We identified six high affinity molecules with dissociation constants ( K
D ) in the nanomolar range (15-550 nM) to the RBD. The highest affinity ligand could be used as an affinity reagent to detect the spike protein in solution by ELISA, and the cocrystal structure of this molecule bound to the RBD demonstrated that it binds to a cryptic binding site, displacing a β-strand near the C-terminus. Our findings provide key mechanistic insight into the binding of peptide ligands to the SARS-CoV-2 spike RBD, and the ligands discovered in this work may find future use as reagents for diagnostic applications., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)- Published
- 2021
- Full Text
- View/download PDF
44. TCR Affinity Controls the Dynamics but Not the Functional Specification of the Antimycobacterial CD4 + T Cell Response.
- Author
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Bhattacharyya ND, Counoupas C, Daniel L, Zhang G, Cook SJ, Cootes TA, Stifter SA, Bowen DG, Triccas JA, Bertolino P, Britton WJ, and Feng CG
- Subjects
- Animals, Cells, Cultured, Mice, Mice, Inbred C57BL, Mice, Knockout, Mice, Transgenic, CD4-Positive T-Lymphocytes immunology, Mycobacterium bovis immunology, Receptors, Antigen, T-Cell immunology
- Abstract
The quality of T cell responses depends on the lymphocytes' ability to undergo clonal expansion, acquire effector functions, and traffic to the site of infection. Although TCR signal strength is thought to dominantly shape the T cell response, by using TCR transgenic CD4
+ T cells with different peptide:MHC binding affinity, we reveal that TCR affinity does not control Th1 effector function acquisition or the functional output of individual effectors following mycobacterial infection in mice. Rather, TCR affinity calibrates the rate of cell division to synchronize the distinct processes of T cell proliferation, differentiation, and trafficking. By timing cell division-dependent IL-12R expression, TCR affinity controls when T cells become receptive to Th1-imprinting IL-12 signals, determining the emergence and magnitude of the Th1 effector pool. These findings reveal a distinct yet cooperative role for IL-12 and TCR binding affinity in Th1 differentiation and suggest that the temporal activation of clones with different TCR affinity is a major strategy to coordinate immune surveillance against persistent pathogens., (Copyright © 2021 by The American Association of Immunologists, Inc.)- Published
- 2021
- Full Text
- View/download PDF
45. Synthesis and evaluation of pyridine-derived bedaquiline analogues containing modifications at the A-ring subunit.
- Author
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Barbaro L, Nagalingam G, Triccas JA, Tan L, West NP, Baell JB, and Priebbenow DL
- Abstract
Despite promising efficacy, the clinical use of the anti-tubercular therapeutic bedaquiline has been restricted due to safety concerns. To date, limited SAR studies have focused on the quinoline ring (A-ring), and as such, we set out to explore modifications within this region in an attempt to discover new bedaquiline variants with an improved safety profile. We herein report the development of unique synthetic strategies that facilitated access to novel bedaquiline analogues leading to the discovery that anti-tubercular activity could be retained following replacement of the quinoline motif with pyridine heterocycles. This discovery is anticipated to open up multiple new avenues for exploration in the design of improved anti-tubercular therapeutics., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)
- Published
- 2021
- Full Text
- View/download PDF
46. Intrapulmonary vaccination with delta-inulin adjuvant stimulates non-polarised chemotactic signalling and diverse cellular interaction.
- Author
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Ferrell KC, Stewart EL, Counoupas C, Ashhurst TM, Britton WJ, Petrovsky N, and Triccas JA
- Subjects
- Adjuvants, Immunologic, Animals, Female, Immunity, Innate, Immunization, Inulin immunology, Lymphocyte Activation, Mice, Mice, Inbred C57BL, Receptors, Antigen, T-Cell, gamma-delta metabolism, Vaccination, Inulin analogs & derivatives, Lung immunology, Mucosal-Associated Invariant T Cells immunology, T-Lymphocytes immunology, Vaccines immunology
- Abstract
There is an urgent need for novel vaccination strategies to combat respiratory pathogens. Mucosal vaccine delivery is an attractive option as it directly targets the site of infection; however, preclinical development has been hindered by a lack of suitable mucosal adjuvants and a limited understanding of their immune effects in the lung environment. Herein, we define the early immune events following the intrapulmonary delivery of a vaccine incorporating the adjuvant delta-inulin. Analysis of the early inflammatory response showed vaccine-induced innate cell recruitment to lungs and local lymph nodes (LN) was transient and non-polarised, correlating with an increase in pulmonary chemotactic factors. Use of fluorescently labelled adjuvant revealed widespread tissue dissemination of adjuvant particles, coupled with broad cellular uptake and transit to the lung-draining LN by a range of innate immune cells. Mass cytometric analysis revealed extensive phenotypic changes in innate and adaptive cell subsets induced by vaccination; this included identification of unconventional lymphocytes such as γδ-T cells and MAIT cells that increased following vaccination and displayed an activated phenotype. This study details a comprehensive view of the immune response to intrapulmonary adjuvant administration and provides pre-clinical evidence to support delta-inulin as a suitable adjuvant for pulmonary vaccines.
- Published
- 2021
- Full Text
- View/download PDF
47. Advax adjuvant formulations promote protective immunity against aerosol Mycobacterium tuberculosis in the absence of deleterious inflammation and reactogenicity.
- Author
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Quan DH, Counoupas C, Nagalingam G, Pinto R, Petrovsky N, Britton WJ, and Triccas JA
- Subjects
- Adjuvants, Immunologic, Aerosols, Animals, Inflammation, Inulin analogs & derivatives, Mice, Mice, Inbred C57BL, Mycobacterium tuberculosis, Tuberculosis Vaccines
- Abstract
The development of safe and effective adjuvants is a critical goal of vaccine development programs. In this report, we defined the immunostimulatory profile and protective effect against aerosol Mycobacterium tuberculosis infection of vaccine formulations incorporating the semi-crystalline adjuvant δ-inulin (Advax). Advax formulated with CpG oligonucleotide and the QS-21 saponin (Advax
CpQS ) was the most effective combination, demonstrated by the capacity of CysVac2/AdvaxCpQS to significantly reduce the bacterial burden in the lungs of M. tuberculosis-infected mice. CysVac2/AdvaxCpQS protection was associated with rapid influx of neutrophils, macrophages and monocytes to the site of vaccination and the induction of antigen-specific IFN-γ+ /IL-2+ /TNF+ polyfunctional CD4+ T cells in the lung. When compared to the highly potent adjuvant combination of monophosphoryl lipid A and dimethyldioctadecylammonium bromide (MPL/DDA), AdvaxCpQS imparted a similar level of protective efficacy yet without the profound stimulation of inflammatory cytokines and vaccination site ulceration observed with MPL/DDA. Addition of DDA to CysVac2/AdvaxCpQS further improved the protective effect of the vaccine, which correlated with increased polyfunctional CD4+ T cells in the lung but with no increase in vaccine reactogenicity. The data demonstrate that Advax formulations can decouple protective tuberculosis immunity from reactogenicity, making them ideal candidates for human application., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: N.P. is an inventor on patents over Advax and has interests in Vaxine Pty Ltd, which owns interests in the Advax patents. W.B., R.P. and J.T. are inventors on patents describing CysVac2. The authors declare that they have no known competing financial interests., (Copyright © 2021 Elsevier Ltd. All rights reserved.)- Published
- 2021
- Full Text
- View/download PDF
48. Mucosal delivery of a multistage subunit vaccine promotes development of lung-resident memory T cells and affords interleukin-17-dependent protection against pulmonary tuberculosis.
- Author
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Counoupas C, Ferrell KC, Ashhurst A, Bhattacharyya ND, Nagalingam G, Stewart EL, Feng CG, Petrovsky N, Britton WJ, and Triccas JA
- Abstract
The development of effective vaccines against bacterial lung infections requires the induction of protective, pathogen-specific immune responses without deleterious inflammation within the pulmonary environment. Here, we made use of a polysaccharide-adjuvanted vaccine approach to elicit resident pulmonary T cells to protect against aerosol Mycobacterium tuberculosis infection. Intratracheal administration of the multistage fusion protein CysVac2 and the delta-inulin adjuvant Advax™ (formulated with a TLR9 agonist) provided superior protection against aerosol M. tuberculosis infection in mice, compared to parenteral delivery. Surprisingly, removal of the TLR9 agonist did not impact vaccine protection despite a reduction in cytokine-secreting T cell subsets, particularly CD4
+ IFN-γ+ IL-2+ TNF+ multifunctional T cells. CysVac2/Advax-mediated protection was associated with the induction of lung-resident, antigen-specific memory CD4+ T cells that expressed IL-17 and RORγT, the master transcriptional regulator of Th17 differentiation. IL-17 was identified as a key mediator of vaccine efficacy, with blocking of IL-17 during M. tuberculosis challenge reducing phagocyte influx, suppressing priming of pathogen-specific CD4+ T cells in local lymph nodes and ablating vaccine-induced protection. These findings suggest that tuberculosis vaccines such as CysVac2/Advax that are capable of eliciting Th17 lung-resident memory T cells are promising candidates for progression to human trials.- Published
- 2020
- Full Text
- View/download PDF
49. Structure-Activity Relationships of cyclo (l-Tyrosyl-l-tyrosine) Derivatives Binding to Mycobacterium tuberculosis CYP121: Iodinated Analogues Promote Shift to High-Spin Adduct.
- Author
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Rajput S, McLean KJ, Poddar H, Selvam IR, Nagalingam G, Triccas JA, Levy CW, Munro AW, and Hutton CA
- Subjects
- Cytochrome P-450 Enzyme System chemistry, Models, Molecular, Protein Binding, Protein Conformation, Structure-Activity Relationship, Cytochrome P-450 Enzyme System metabolism, Dipeptides chemistry, Dipeptides metabolism, Halogenation, Mycobacterium tuberculosis enzymology
- Abstract
A series of analogues of cyclo (l-tyrosyl-l-tyrosine), the substrate of the Mycobacterium tuberculosis enzyme CYP121, have been synthesized and analyzed by UV-vis and electron paramagnetic resonance spectroscopy and by X-ray crystallography. The introduction of iodine substituents onto cyclo (l-tyrosyl-l-tyrosine) results in sub-μM binding affinity for the CYP121 enzyme and a complete shift to the high-spin state of the heme Fe
III . The introduction of halogens that are able to interact with heme groups is thus a feasible approach to the development of next-generation, tight binding inhibitors of the CYP121 enzyme, in the search for novel antitubercular compounds.- Published
- 2019
- Full Text
- View/download PDF
50. Bengamides display potent activity against drug-resistant Mycobacterium tuberculosis.
- Author
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Quan DH, Nagalingam G, Luck I, Proschogo N, Pillalamarri V, Addlagatta A, Martinez E, Sintchenko V, Rutledge PJ, and Triccas JA
- Subjects
- Antitubercular Agents chemistry, Azepines chemistry, Drug Interactions, Microbial Sensitivity Tests, Antitubercular Agents pharmacology, Azepines pharmacology, Drug Resistance, Bacterial drug effects, Mycobacterium tuberculosis drug effects
- Abstract
Mycobacterium tuberculosis infects over 10 million people annually and kills more people each year than any other human pathogen. The current tuberculosis (TB) vaccine is only partially effective in preventing infection, while current TB treatment is problematic in terms of length, complexity and patient compliance. There is an urgent need for new drugs to combat the burden of TB disease and the natural environment has re-emerged as a rich source of bioactive molecules for development of lead compounds. In this study, one species of marine sponge from the Tedania genus was found to yield samples with exceptionally potent activity against M. tuberculosis. Bioassay-guided fractionation identified bengamide B as the active component, which displayed activity in the nanomolar range against both drug-sensitive and drug-resistant M. tuberculosis. The active compound inhibited in vitro activity of M. tuberculosis MetAP1c protein, suggesting the potent inhibitory action may be due to interference with methionine aminopeptidase activity. Tedania-derived bengamide B was non-toxic against human cell lines, synergised with rifampicin for in vitro inhibition of bacterial growth and reduced intracellular replication of M. tuberculosis. Thus, bengamides isolated from Tedania sp. show significant potential as a new class of compounds for the treatment of drug-resistant M. tuberculosis.
- Published
- 2019
- Full Text
- View/download PDF
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