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The role of immunosuppressive therapy on SARS-CoV-2 infection risk and COVID-19 severity remains unclear in unvaccinated solid organ transplant recipients. We included 1957 organ transplant recipients between July 2020 and April 2021 to analyze whether baseline immunosuppressive therapy and other risk factors are associated with SARS-CoV-2 infection and severe COVID-19. In total, 247 (12.6%) had SARS-CoV-2 (defined as positive nasopharyngeal swab and/or positive antibody titer). Of these, 57 (23.1%) had severe COVID-19, defined as oxygen supplementation, intensive care unit admission or death. Multivariable analysis identified diabetes (hazard ratio (HR) 1.39 (95% confidence interval (CI) 1.05–1.83)), chronic lung disease (HR 1.71 (95% CI 1.13–2.60)) and contact with a COVID-19 positive individual (HR 3.61 (95% CI 2.61–4.99) as independent risk factors for SARS-CoV-2 infection. There was no association between immunosuppressive therapy and infection risk. Severe COVID-19 was multivariably associated with hypertension (OR 5.45 (95% CI 1.66–17.84)), chronic kidney disease (OR 3.55 (95% CI 1.75–7.19)), corticosteroid use (OR 2.93 (95% CI 1.03–2.55)) and having a COVID-19 positive housemate (OR 6.77 (95% CI 2.65–17.28)). In conclusion, baseline corticosteroid use, but no other immunosuppressive agent, is independently associated with severe COVID-19 in unvaccinated SOT recipients after correction for hypertension, chronic kidney disease, housemates affected by COVID-19 and transplant type. [ABSTRACT FROM AUTHOR]

Lassa virus (LASV) outbreaks in West Africa pose a significant public health threat. We investigated the infection phenotype and transmission (horizontal and vertical) of LASV strain Ba366 in its natural host, Mastomys natalensis. Here we analyze viral RNA levels in body fluids, virus titers in organs and antibody presence in blood. In adults and 2-week-old animals, LASV causes transient infections with subsequent seroconversion. However, mice younger than two weeks exhibit persistent infections lasting up to 16 months despite antibody presence. LASV can be detected in various body fluids, organs, and cell types, primarily in lung, kidney, and gonadal epithelial cells. Despite the systemic virus presence, no pathological alterations in organs are observed. Infected animals efficiently transmit the virus throughout their lives. Our findings underscore the crucial role of persistently infected individuals, particularly infected females and their progeny, in LASV dissemination within the host population. Mastomys natalensis, a mouse found closely to rural human dwellings in Sub-Saharan Africa, is a major reservoir for Lassa Virus (LASV). Here, the authors show that LASV causes transient infections in adult M. natalensis, but persistent infections in young animals despite antibodies. LASV is found in various organs without causing pathology and infected animals efficiently transmit the virus. [ABSTRACT FROM AUTHOR]

Unlike most other picornaviruses, foot-and-mouth disease (FMD) intact virions (146S) dissociate easily into small pentameric subunits (12S). This causes a dramatically decreased immunogenicity by a mechanism that remains elusive. Here, we present the high-resolution structures of 12S (3.2 Å) and its immune complex of a single-domain antibody (VHH) targeting the particle interior (3.2 Å), as well as two 146S-specific VHHs complexed to distinct sites on the 146S capsid surface (3.6 Å and 2.9 Å). The antigenic landscape of 146S is depicted using 13 known FMD virus-antibody complexes. Comparison of the immunogenicity of 146S and 12S in pigs, focusing on the resulting antigenic sites and incorporating structural analysis, reveals that dissociation of 146S leads to structural alteration and destruction of multiple epitopes, resulting in significant differences in antibody profiles/lineages induced by 12S and 146S. Furthermore, 146S generates higher synergistic neutralizing antibody titers compared to 12S, whereas both particles induce similar total FMD virus specific antibody titers. This study can guide the structure-based rational design of novel multivalent and broad-spectrum recombinant vaccines for protection against FMD. Foot-and-mouth disease vaccine efficacy is reduced when full virion 146S dissociates into pentameric 12S subunit. Here, the authors elucidate the molecular basis of this compromised immunogenicity by comparing antigenicity, humoral immunogenicity and structures of 146S and 12S particles. [ABSTRACT FROM AUTHOR]

Human cytomegalovirus (hCMV) is a ubiquitous latent persistent herpesvirus infecting 60–90% of the population worldwide. hCMV carriage in immunocompetent people is asymptomatic; thus, hCMV can be considered a component of normative aging. However, hCMV powerfully modulates many features of the immune, and likely other, systems and organs. Questions remain as to how hCMV carriage affects the human host. We used anti-CMV antibody titers as a stratifying criterion to examine the impact of "intensity" of hCMV infection as a potential biomarker of aging, inflammation, and immune homeostasis in a cohort of 247 participants stratified into younger (21–40 years) and older (> 65 years of age) groups. We showed that anti-CMV antibody titers increased with age and directly correlated to increased levels of soluble tumor necrosis factor (sTNFR) I in younger but not older participants. CD8 + cell numbers were reduced in the older group due to the loss in CD8 + T naïve (Tn) cells. In CMV carriers and, in particular, in anti-CMV Ab-high participants, this loss was mitigated or reversed by an increase in the numbers of CD8 + T effector memory (Tem) and T effector memory reexpressing CD45RA (Temra) cells. Analysis of CD38, HLA-DR, and CD57 expression revealed subset (CD4 or CD8)-specific changes that correlated with anti-CMV Ab levels. In addition, anti-CMV Ab levels predicted anti-CMV CD8 T cell responsiveness to different CMV open reading frames (ORFs) selectively in older participants, which correlated to the transcriptional order of expression of specific CMV ORFs. Implications of these results for the potential predictive value of anti-CMV Ab titers during aging are discussed. [ABSTRACT FROM AUTHOR]

Epigenetic regulation plays a central role in the regulation of a number of cellular processes such as proliferation, differentiation, cell cycle, and apoptosis. In particular, small molecule epigenetic modulators are key elements that can effectively influence gene expression by precisely regulating the epigenetic state of cells. To identify useful small-molecule regulators that enhance the expression of recombinant proteins in Chinese hamster ovary (CHO) cells, we examined a novel dual-HDAC/LSD1 inhibitor I-4 as a supplement for recombinant CHO cells. Treatment with 2 μM I-4 was most effective in increasing monoclonal antibody production. Despite cell cycle arrest at the G1/G0 phase, which inhibits cell growth, the addition of the inhibitor at 2 µM to monoclonal antibody-expressing CHO cell cultures resulted in a 1.94-fold increase in the maximal monoclonal antibody titer and a 2.43-fold increase in specific monoclonal antibody production. In addition, I-4 significantly increased the messenger RNA levels of the monoclonal antibody and histone H3 acetylation and methylation levels. We also investigated the effect on HDAC-related isoforms and found that interference with the HDAC5 gene increased the monoclonal antibody titer by 1.64-fold. The results of this work provide an effective method of using epigenetic regulatory strategies to enhance the expression of recombinant proteins in CHO cells. Key points: • HDAC/LSD1 dual-target small molecule inhibitor can increase the expression level of recombinant monoclonal antibodies in CHO cells. • By affecting the acetylation and methylation levels of histones in CHO cells and downregulating HDAC5, the production of recombinant monoclonal antibodies increased. • It provides an effective pathway for applying epigenetic regulation strategies to enhance the expression of recombinant proteins. [ABSTRACT FROM AUTHOR]

Rituximab occasionally induces reactivation of hepatitis C virus (HCV) in patients with resolved HCV infection, sometimes with fatal consequences. As rituximab has become one of the first-line therapies for the treatment of phospholipase A2 receptor (PLA2R)-associated membranous nephropathy (MN) and is more widely used, there is a lack of studies reporting the effectiveness and safety of rituximab in patients with PLA2R-associated MN and resolved HCV infection. A single-center retrospective study was conducted on PLA2R-associated membranous nephropathy (MN) patients who were HCVAb positive but HCV-RNA negative and treated with rituximab. A total of 598 adult patients with PLA2R-associated MN who underwent rituximab therapy were screened. General clinical information, including gender, age, pathological data, and previous treatment plans, was collected from medical records. Routine blood tests, liver and kidney function assessments, blood lipid profiles, 24-h urine protein levels, anti-PLA2R antibody titers, circulating B-cell counts, and HCV viral loads were measured at the time of rituximab infusion and repeated at intervals of 1–3 months post-rituximab administration. A total of 8 patients were enrolled, with a median follow-up period of 19.00 (range: 16.00–25.25) months. Among the 8 patients, 5 were male, and the mean age was 50.13 ± 4.29 years. Histological findings indicated that tubuloreticular inclusions, mesangial deposits, intramembranous deposits, and subendothelial deposits were not observed in any of the 8 patients. The overall 1-year remission rate for these patients was 75%, accompanied by a significant reduction in proteinuria. Additionally, blood albumin levels increased significantly, and renal function remained stable. No increase in HCV viral load and stable liver function tests were observed throughout the entire follow-up period. This study suggested that on the basis of successful eradication of HCV virus with antiviral drugs, rituximab can effectively induce clinical remission of patients with PLA2R associated MN and resolved HCV infection, and does not lead to a significant increase in HCV virus load. However, this finding is based on a very small sample size and should be confirmed in larger clinical trials. [ABSTRACT FROM AUTHOR]

Background: Anti leucine-rich, glioma inactivated 1 (LGI1) antibody-associated autoimmune encephalitis (AE) is the second most common AE, where the trafficking and recycling of the pathogenic immunoglobulin (IgG) can be controlled by the neonatal crystallizable fragment receptor (FcRn), making the latter as a candidate therapeutic target. Efgartigimod is an antagonist of FcRn, its ability to increase the degradation of IgGs and improve the health and quality of life of patients. ADAPT trail indicated its rapid efficacy and safety on myasthenia gravis. However, there is currently no case reported using efgartigimod for the treatment of anti-LGI1-associated AE. Case description: The patient presented with five episodes of generalized tonic–clonic seizures in the past 2 weeks. The patient had no abnormal signs on magnetic resonance imaging. Electroencephalogram examinations showed an increase in bilateral symmetric or asymmetric slow activity, without any clear epileptic waves. The cerebrospinal fluid (CSF) examination results indicated a slight increase in protein (47 mg/dL). The anti-LGI1 antibody titer in serum was 1:100 and that in CSF was 1:3.2. The treatment with intravenous methylprednisolone 1000 mg once a day combined with levetiracetam tablets failed to completely control the patient's seizures. Thus, 10 mg/kg efgartigimod was administered intravenously once a week for 2 weeks. After 2 weeks of treatment, serum levels of anti-LGI1 antibody and IgG decreased and the patient's epilepsy did not recur in the next 3 months. Conclusions: This is the first case report of using efgartigimod to treat anti-LGI1-associated AE. The combination of efgartigimod and methylprednisolone resulted in favorable outcomes, indicating that this is an optional treatment plan. [ABSTRACT FROM AUTHOR]

Abdominal angiostrongyliasis (AA) is a zoonotic and severe parasitic infection caused by Angiostrongylus costaricensis. AA is currently diagnosed by the observation of A. costaricensis-compatible structures in biopsies or the detection of antibodies in serological tests. However, molecular methods targeting homologous sequences of A. costaricensis have not been designed before, and therefore, an HRM-coupled qPCR was developed to detect the internal transcribed spacer 1 (ITS1) of the parasite. The present assay successfully amplified DNA of A. costaricensis obtained from different hosts and identified slight sequence differences through the HRM analysis. The detection limit of the HRM-qPCR was 0.00036 ng/µL, 1.0 ng/µL, and 0.1 ng/µL when A. costaricensis DNA was diluted in nuclease-free water, whole blood, and sera, respectively, which highlights its potential use for cell-free DNA detection. Moreover, the reaction did not cross-amplify DNA of Angiostrongylus cantonensis, Strongyloides stercoralis, and other nematodes, thus emphasizing its specificity. Additionally, the assay tested positive in formalin-fixed paraffin embedded biopsies with visible A. costaricensis adults or eggs, but not in samples without evident parasites or a low number of larvae, which suggests that the reaction is useful for confirming the presence of the nematode in clinical samples. Finally, DNA of sera from patients with AA was evaluated with the HRM-qPCR but none tested positive, possibly due to long storage periods of the samples which could have led to cfDNA degradation. These results indicate that this assay may be useful in the confirmation of AA and its prospection for cell-free DNA detection protocols. [ABSTRACT FROM AUTHOR]

Heparin-induced thrombocytopenia (HIT) is an antibody-mediated immune response against complexes of heparin and platelet factor 4 (PF4). The electrostatic interaction between heparin and PF4 is critical for the anti-PF4/heparin antibody response seen in HIT. The binding of metal cations to heparin induces conformational changes and charge neutralization of the heparin molecule, and cation-heparin binding can modulate the specificity and affinity for heparin-binding partners. However, the effects of metal cation binding to heparin in the context of anti-PF4/heparin antibody response have not been determined. Here, we utilized inductively coupled plasma mass spectrometry (ICP-MS) to quantify 16 metal cations in patient plasma and tested for correlation with anti-PF4/heparin IgG levels and platelet count after clinical suspicion of HIT in a cohort of heparin-treated patients. The average age of the cohort (n = 32) was 60.53 (SD = 14.31) years old, had a mean anti-PF4/heparin antibody optical density [OD405] of 0.93 (SD = 1.21) units, and was primarily female (n = 23). Patients with positive anti-PF4/heparin antibody test results (OD405 ≥ 0.5 units) were younger, had increased weight and BMI, and were more likely to have a positive serotonin release assay (SRA) result compared to antibody-negative patients. We observed statistical differences between antibody-positive and -negative groups for sodium and aluminum and significant correlations of anti-PF4/heparin antibody levels with sodium and silver. While differences in sodium concentrations were associated with antibody-positive status and correlated with antibody levels, no replication was performed. Additional studies are warranted to confirm our observed association, including in vitro binding studies and larger observational cohorts. [ABSTRACT FROM AUTHOR]

Infections, despite vaccination, can be clinically consequential for frail nursing home residents (NHR). Poor vaccine-induced antibody quality may add risk for such subsequent infections and more severe disease. We assessed antibody binding avidity, as a surrogate for antibody quality, among NHR and healthcare workers (HCW). We longitudinally sampled 112 NHR and 52 HCWs who received the BNT162b2 mRNA vaccine after each dose up to the Wuhan-BA.4/5-based Omicron bivalent boosters. We quantified anti-spike, anti-receptor binding domain (RBD), and avidity levels to the ancestral Wuhan, Delta, and Omicron BA.1 & 4/5 strains. The primary vaccination series produced substantial anti-spike and RBD levels which were low in avidity against all strains tested. Antibody avidity progressively increased in the 6–8 months that followed. Avidity significantly increased after the 1st booster but not for subsequent boosters. This study underscores the importance of booster vaccination among NHR and HCWs. The 1st booster dose increases avidity, increasing vaccine-induced functional antibody. The higher cross-reactivity of higher avidity antibodies to other SARS-CoV-2 strains should translate to better protection from ever-evolving strains. Higher avidities may help explain how the vaccine's protective effects persist despite waning antibody titers after each vaccine dose. [ABSTRACT FROM AUTHOR]

Although HPV vaccines are highly efficacious, a notable proportion of quadrivalent vaccinees are HPV18 seronegative post-vaccination. We have investigated this findings' validity by comparing vaccine-induced antibody responses using two different immunoassays. 6558 16–17-year-old females participated in the FUTURE II (NCT00092534) and PATRICIA (NCT00122681) trials in 2002–2004. Both the quadrivalent and bivalent vaccine recipients (QVR and BVR) received three doses. Twelve-year follow-up for 648 vaccinees was conducted by the Finnish Maternity Cohort. The presence of neutralising and binding HPV antibodies was analysed via HPV pseudovirion-based neutralisation and pseudovirion-binding assays. Four percent and 14.3% of the QVRs were seronegative for neutralising and binding antibodies to HPV16 and HPV18, respectively. No BVRs were HPV16/18 seronegative post-vaccination. The antibody titres were strongly correlated between the assays, Pearson's correlation coefficient, r[HPV16] = 0.92 and 0.85, and r[HPV18] = 0.91 and 0.86 among the QVRs and BVRs respectively. Fourteen percent of QVRs lacked detectable HPV18 antibodies in long-term follow-up. [ABSTRACT FROM AUTHOR]

Hepatitis Delta Virus (HDV), a satellite virus of Hepatitis B virus, exacerbates liver damage in affected individuals. Screening for HDV antibodies in HBsAg positive patients is recommended, but the diagnostic accuracy of serological tests remains uncertain. This review aimed to assess the diagnostic accuracy of serological tests for HDV. We searched PubMed, Web of Science, Cochrane Central Register of Controlled Trials, Scopus etc. for relevant studies. Studies measuring the sensitivity and specificity of serological HDV tests against PCR as a reference standard were included. Pooled sensitivity and specificity for each test method and sero-marker were calculated. The review included six studies with 11 study arms, evaluating ARCHITECT immunoassay, EIA, ELISA, QMAC, RIA, and Western Blot test methods targeting Anti-HDV IgG, Total anti-HDV and Anti-HDV IgM. Sensitivities for Anti-HDV IgG, Total Anti-HDV and Anti-HDV IgM, tests were 97.4%, 51.9%, and 62.0%, respectively, with specificities of 95.3%, 80.0%, and 85.0%. Our findings, with its limited number of studies, suggest that HDV serological tests, particularly those identifying Anti IgG exhibit high accuracy and can serve as effective screening tools for HDV. [ABSTRACT FROM AUTHOR]

A randomized, active-controlled, double-blind, first-in-human, phase 1 study was conducted in healthy Korean adults to evaluate the safety, tolerability, and immunogenicity of EuNmCV-5, a new pentavalent meningococcal vaccine targeting serogroups A, C, W, X, and Y. Sixty participants randomly received a single dose of either EuNmCV-5 or MenACWY-CRM, a quadrivalent vaccine containing serogroups A, C, W, and Y. Safety was assessed through monitoring anaphylactic reactions, adverse events for 28 days, and serious adverse events over 180 days. Immunogenicity was assessed via rabbit complement-dependent serum bactericidal antibody (rSBA) assay. EuNmCV-5 was safe, well-tolerated, and elicited a substantial antibody titer increase. The seroprotection rates exceeded 96.7%, and the seroconversion rates were over 85% for all the targeted serogroups. It showed higher seroconversion rates against serogroups A and C (p = 0.0016 and 0.0237, respectively) and elicited a substantial increase in GMT for all targeted serogroups compared to the MenACWY-CRM. ClinicalTrials.gov identifier: NCT05739292. [ABSTRACT FROM AUTHOR]

Herpes simplex virus-2 encephalitis (HSV2E) in immunocompetent adults is exceptionally rare, and the subsequent onset of autoimmune encephalitis after HSV2E is even less common. This report presents the inaugural Chinese case of anti-N-methyl-d-aspartate receptor encephalitis (NMDARE) induced by HSV2E, confirmed via metagenomic next-generation sequencing (mNGS). The patient demonstrated a favorable response to intravenous immunoglobulin (IVIG) monotherapy. This case emphasizes the importance of considering autoimmune encephalitis in patients exhibiting new or recurrent neurological symptoms after HSV2E recovery. Comprehensive mNGS and neuronal antibody testing are essential for timely diagnosis. Moreover, IVIG monotherapy can serve as an effective treatment for NMDARE induced by HSV2, providing a viable alternative, particularly when steroid therapy is contraindicated. [ABSTRACT FROM AUTHOR]

Antibodies for treatment and prophylaxis against SARS-CoV-2 are needed particularly for immunocompromised individuals, who cannot adequately benefit from vaccination. To address this need, Aerium Therapeutics is developing antibodies targeting the SARS-CoV-2 spike protein. A bioanalytical method to quantify fully human monoclonal antibodies in a population with widely varying anti-spike antibody titers is required to investigate the pharmacokinetics of these antibodies in clinical trials. To eliminate interference from endogenous anti-spike protein antibodies, an HPLC–MS/MS assay was developed to quantify the investigational monoclonal antibodies (AER001 and AER002) by targeting signature peptides spanning the monoclonal antibodies' CDR regions. By optimizing and comparing affinity capture and ammonium sulphate precipitation, it was demonstrated that both procedures allowed accurate and precise quantification of AER001 and AER002 in human serum with comparable sensitivity. Ammonium sulphate precipitation outperformed immunocapture due to its simplicity and speed at lower cost and a full bioanalytical method validation was performed in human serum. The assay was also validated for human nasal lining fluid extract with a 50-fold lower limit of quantification and was shown to deliver similar sensitivity to previously published affinity capture HPLC–MS/MS assays. Finally, the CDR-derived signature peptides were also generated by tryptic digestion of blank serum in some individuals, an important caveat for HPLC–MS/MS strategies targeting human monoclonal antibodies. In summary, the presented results show that ammonium sulphate precipitation and HPLC–MS/MS allow accurate and precise quantification of monoclonals in clinical studies. The developed methods demonstrate that HPLC–MS/MS can reliably quantify human monoclonal antibodies even when endogenous antibodies with overlapping specificities are present and are crucial for the clinical testing of two investigational COVID-19 monoclonals. [ABSTRACT FROM AUTHOR]

This study reports on the immunogenicity and biodistribution of H5 hemagglutinin (HA)-based self-amplifying (sa) mRNA vaccines in mice. Four sa-mRNA vaccines encoding either a secreted full-length HA, a secreted HA head domain, a secreted HA stalk domain, or a full-length membrane-anchored HA were investigated. All vaccines elicited an adaptive immune response. However, the full-length HA sa-RNA vaccines demonstrated superior performance compared to head and stalk domain vaccines. The antibody titers positively correlated with the vaccine dose. Cellular immune responses and antigen-specific IgA antibodies in the lungs were also observed. The comparison of the sa-mRNA vaccines encoding the secreted and membrane-anchored full-length HA revealed that anchoring of the HA to the membrane significantly enhanced the antibody and cellular responses. In addition to the injection site, the intramuscularly injected sa-mRNA-LNPs were also detected in the draining lymph nodes, spleen, and to a lesser extent, in the lung, kidney, liver, and heart. [ABSTRACT FROM AUTHOR]

Although Omicron RBD of SARS-CoV-2 accumulates many mutations, the backbone region (truncated RBD) of spike protein is highly conserved. Here, we designed several subunit vaccines by keeping the conserved spike backbone region of SARS-CoV-2 Omicron BA.1 subvariant (S-6P-no-RBD), or inserting the RBD of Delta variant (S-6P-Delta-RBD), Omicron (BA.5) variant (S-6P-BA5-RBD), or ancestral SARS-CoV-2 (S-6P-WT-RBD) to the above backbone construct, and evaluated their ability to induce immune responses and cross-protective efficacy against various SARS-CoV-2 variants and SARS-CoV. Among the four subunit vaccines, S-6P-Delta-RBD protein elicited broad and potent neutralizing antibodies against all SARS-CoV-2 variants tested, including Alpha, Beta, Gamma, and Delta variants, the BA.1, BA.2, BA.2.75, BA.4.6, and BA.5 Omicron subvariants, and the ancestral strain of SARS-CoV-2. This vaccine prevented infection and replication of SARS-CoV-2 Omicron, and completely protected immunized mice against lethal challenge with the SARS-CoV-2 Delta variant and SARS-CoV. Sera from S-6P-Delta-RBD-immunized mice protected naive mice against challenge with the Delta variant, with significantly reduced viral titers and without pathological effects. Protection correlated positively with the serum neutralizing antibody titer. Overall, the designed vaccine has potential for development as a universal COVID-19 vaccine and/or a pan-sarbecovirus subunit vaccine that will prevent current and future outbreaks caused by SARS-CoV-2 variants and SARS-related CoVs. [ABSTRACT FROM AUTHOR]

Background: The approved screening test for HCV infection among blood donors is the HCV antibody test. The diagnostic performances of the available immunoassays in the market that target different HCV antigens have not yet been thoroughly analyzed. Our study aimed to assess the diagnostic performances of two different chemiluminescence immunoassay (CLIA) assays. Methods: We analyzed 1909 samples using two assay systems (COBAS e601 ROCHE® & Vitros 3600 ORTHO®) and evaluated the agreement of each with the gold standard method ELISA, as well as studying their diagnostic performances. Results: The Cohen's Kappa statistics revealed excellent agreement between ELISA and both CLIA methods performed on Cobas e 601 ROCHE and Vitrous 3600 ORTHO (0.81 & 0.994 respectively). The sensitivities and positive predictive values were 95.05% and 73.85% for Cobas e 601 ROCHE, 100.00%, and 98.97% for Vitrous 3600 ORTHO, respectively. Conclusions: Excellent diagnostic performance was detected by both assays; however, Vitros 3600 ORTHO outperformed Cobas e 601 ROCHE in terms of sensitivity and specificity. [ABSTRACT FROM AUTHOR]

Immunosuppressants, such as methotrexate (MTX), can suppress the COVID-19 vaccine response in patients with autoimmune diseases. Thus, this study aims to evaluate the effects of MTX hold following COVID-19 vaccination on vaccine efficacy response. A systematic review and meta-analysis of relevant studies retrieved from Web of Science, SCOPUS, PubMed, and CENTRAL from inception until Oct 1, 2023, was conducted. Covidence was used to screen the eligible articles, and all relevant outcomes data were synthesized using risk ratios (RRs) or standardized mean differences (SMDs) with 95% confidence intervals (CIs) in meta-analysis models within RevMan 5.4. PROSPERO ID: CRD42024511628. Four studies with a total of 762 patients with autoimmune inflammatory disorders were included. Holding MTX following the COVID-19 vaccination for approximately 2 weeks was associated with significantly higher antibody titer (SMD: 0.70, 95% CI [0.54, 0.87], P < 0.00001). However, the flare rate was significantly higher in the MTX hold group based on CDAI > 10 or DAS28-CRP > 1.2 either after 1st dose (RR: 2.49 with 95% CI [1.39, 4.47], P = 0.002) or 2nd dose (RR: 2.16 with 95% CI [1.37, 3.41], P = 0.0009) and self-reported disease flare (RR: 1.71 with 95% CI [1.35, 2.17], P < 0.00001). Holding MTX for 2 weeks after the COVID-19 vaccination resulted in significantly higher antibody titer but also had a higher disease flare rate, necessitating cautious clinical monitoring during this period. There is still a need to investigate safer MTX hold duration, considering patients' vulnerability to COVID-19, disease status, and demographics while adopting this strategy. [ABSTRACT FROM AUTHOR]

Aquaporin 4-immunoglobulin G (AQP4-IgG) specifically targets aquaporin 4 in approximately 80% of Neuromyelitis Optica Spectrum Disorder (NMOSD) cases. NMOSD is presently categorized as anti-AQP4-antibody (Ab) positive or negative based on AQP4-Ab presence. The association between antibody titers and patient prognosis remains unclear. Therefore, the present study explores the correlation between severe attacks and serum AQP4 Ab titers in patients with neuromyelitis optica spectrum disorder. Data were gathered retrospectively from 546 patients with NMOSD between September 1, 2009, and December 1, 2021. Patients were categorized based on their AQP4-Ab titers: AQP4 titer ≥ 1:320 were classified as the high-titer group, AQP4 (+ +), and AQP4 titer of ≤ 1:100 were classified as the low-titer group, AQP4 (+). Clinical characteristics and prognoses between the two groups were compared. Patients with AQP4 (+) exhibited few severe optic neuritis (SON) attacks (false discovery rate [FDR] corrected p < 0.001), a reduced percentage experiencing SON attacks, and a lower incidence of visual disability than patients with AQP4 (+ +). Patients with AQP4 (+ +) and AQP4 (+) NMOSD exhibited significant difference in annual recurrence rate (ARR) (FDR-corrected p < 0.001). The lower AQP4 Ab titer group demonstrated reduced susceptibility to severe relapse with conventional immunosuppressive agents and rituximab (RTX) than the higher titer group. No significant differences in sex, age at onset, coexisting connective tissue diseases, motor disability, or mortality rates were observed between the two groups. Higher AQP4 Ab titers correlated with increased disease severity and visual disability in patients with NMOSD. [ABSTRACT FROM AUTHOR]

Human cases of avian influenza virus (AIV) infections are associated with an age-specific disease burden. As the influenza virus N2 neuraminidase (NA) gene was introduced from avian sources during the 1957 pandemic, we investigate the reactivity of N2 antibodies against A(H9N2) AIVs. Serosurvey of healthy individuals reveal the highest rates of AIV N2 antibodies in individuals aged ≥65 years. Exposure to the 1968 pandemic N2, but not recent N2, protected against A(H9N2) AIV challenge in female mice. In some older adults, infection with contemporary A(H3N2) virus could recall cross-reactive AIV NA antibodies, showing discernable human- or avian-NA type reactivity. Individuals born before 1957 have higher anti-AIV N2 titers compared to those born between 1957 and 1968. The anti-AIV N2 antibodies titers correlate with antibody titers to the 1957 N2, suggesting that exposure to the A(H2N2) virus contribute to this reactivity. These findings underscore the critical role of neuraminidase immunity in zoonotic and pandemic influenza risk assessment. Using more than 300 serum samples from individuals with an age range of 1-88 years old, the authors here show that older adults possess higher breadth of antibody reactivity to avian influenza virus (AIV) neuraminidases, potentially explaining the age-specific risks of AIV human infections. [ABSTRACT FROM AUTHOR]

Evolution of SARS-CoV-2 alters the antigenicity of the immunodominant spike (S) receptor-binding domain and N-terminal domain, undermining the efficacy of vaccines and antibody therapies. To overcome this challenge, we set out to develop a vaccine focusing antibody responses on the highly conserved but metastable S2 subunit, which folds as a spring-loaded fusion machinery. We describe a strategy for prefusion-stabilization and high yield recombinant production of SARS-CoV-2 S2 trimers with native structure and antigenicity. We demonstrate that our design strategy is broadly generalizable to sarbecoviruses, as exemplified with the SARS-CoV-1 (clade 1a) and PRD-0038 (clade 3) S2 subunits. Immunization of mice with a prefusion-stabilized SARS-CoV-2 S2 trimer elicits broadly reactive sarbecovirus antibodies and neutralizing antibody titers of comparable magnitude against Wuhan-Hu-1 and the immune evasive XBB.1.5 variant. Vaccinated mice were protected from weight loss and disease upon challenge with XBB.1.5, providing proof-of-principle for fusion machinery sarbecovirus vaccines. Evolution of viruses undermines the efficacy of vaccines and antibody therapies. To overcome this challenge, authors describe a strategy for prefusion-stabilization to provide proof-of-principle for fusion-machinery sarbecovirus vaccines. [ABSTRACT FROM AUTHOR]

Myasthenia gravis (MG) is an autoimmune disease characterized by muscle fatigability due to acetylcholine receptor (AChR) autoantibodies. To better characterize juvenile MG (JMG), we analyzed 85 pre- and 132 post-pubescent JMG (with a cutoff age of 13) compared to 721 adult MG patients under 40 years old using a French database. Clinical data, anti-AChR antibody titers, thymectomy, and thymic histology were analyzed. The proportion of females was higher in each subgroup. No significant difference in the anti-AChR titers was observed. Interestingly, the proportion of AChR+ MG patients was notably lower among adult MG patients aged between 30 and 40 years, at 69.7%, compared to over 82.4% in the other subgroups. Thymic histological data were examined in patients who underwent thymectomy during the year of MG onset. Notably, in pre-JMG, the percentage of thymectomized patients was significantly lower (32.9% compared to more than 42.5% in other subgroups), and the delay to thymectomy was twice as long. We found a positive correlation between anti-AChR antibodies and germinal center grade across patient categories. Additionally, only females, particularly post-JMG patients, exhibited the highest rates of lymphofollicular hyperplasia (95% of cases) and germinal center grade. These findings reveal distinct patterns in JMG patients, particularly regarding thymic follicular hyperplasia, which appears to be exacerbated in females after puberty. [ABSTRACT FROM AUTHOR]

Acute myeloid leukemia (AML) is fatal in the majority of adults. Identification of new therapeutic targets and their pharmacologic modulators are needed to improve outcomes. Previous studies had shown that immunization of rabbits with normal peripheral WBCs that had been incubated with fluorodinitrobenzene elicited high titer antibodies that bound to a spectrum of human leukemias. We report that proteomic analyses of immunoaffinity-purified lysates of primary AML cells showed enrichment of scaffolding protein IQGAP1. Immunohistochemistry and gene-expression analyses confirmed IQGAP1 mRNA overexpression in various cytogenetic subtypes of primary human AML compared to normal hematopoietic cells. shRNA knockdown of IQGAP1 blocked proliferation and clonogenicity of human leukemia cell-lines. To develop small molecules targeting IQGAP1 we performed in-silico screening of 212,966 compounds, selected 4 hits targeting the IQGAP1-GRD domain, and conducted SAR of the 'fittest hit' to identify UR778Br, a prototypical agent targeting IQGAP1. UR778Br inhibited proliferation, induced apoptosis, resulted in G2/M arrest, and inhibited colony formation by leukemia cell-lines and primary-AML while sparing normal marrow cells. UR778Br exhibited favorable ADME/T profiles and drug-likeness to treat AML. In summary, AML shows response to IQGAP1 inhibition, and UR778Br, identified through in-silico studies, selectively targeted AML cells while sparing normal marrow. [ABSTRACT FROM AUTHOR]

Stonustoxin (SNTX) is a lethal protein found in stonefish venom, responsible for many of the symptoms associated with stonefish envenomation. To counter stonefish venom challenges, antivenom is a well-established and effective solution. In this study, we aimed to produce the recombinant alpha subunit protein of Stonustoxin from Synanceia horrida and prepare antibodies against it The SNTXα gene sequence was optimized for E. coli BL21 (DE3) expression and cloned into the pET17b vector. Following purification, the recombinant protein was subcutaneously injected into rabbits, and antibodies were extracted from rabbit´s serum using a G protein column As a result of codon optimization, the codon adaptation index for the SNTXα cassette increased to 0.94. SDS-PAGE analysis validated the expression of SNTXα, with a band observed at 73.5 kDa with a yield of 60 mg/l. ELISA results demonstrated rabbits antibody titers were detectable up to a 1:256,000 dilution. The isolated antibody from rabbit´s serum exhibited a concentration of 1.5 mg/ml, and its sensitivity allowed the detection of a minimum protein concentration of 9.7 ng. In the neutralization assay the purified antibody against SNTXα protected mice challenged with 2 LD50. In conclusion, our study successfully expressed the alpha subunit of Stonustoxin in a prokaryotic host, enabling the production of antibodies for potential use in developing stonefish antivenom. [ABSTRACT FROM AUTHOR]

We conducted a comprehensive metabolomic analysis of plasma samples obtained from pregnant women who displayed varying post-vaccination antibody titers after receiving mRNA-1273-SARS-CoV-2 vaccines. The study involved 62 pregnant women, all of whom had been vaccinated after reaching 24 weeks of gestation. To quantify post-vaccination plasma antibody titers, we employed binding antibody units (BAU) in accordance with the World Health Organization International Standard. Subsequently, we classified the study participants into three distinct BAU/mL categories: those with high titers (above 2000), medium titers (ranging from 1000 to 2000), and low titers (below 1000). Plasma metabolomic profiling was conducted using 1H nuclear magnetic resonance spectroscopy, and the obtained data were correlated with the categorized antibody titers. Notably, in pregnant women exhibiting elevated anti-SARS-CoV-2 antibody titers, reduced plasma concentrations of acetate and urea were observed. A significant negative correlation between these compounds and antibody titers was also evident. An analysis of metabolomics pathways revealed significant inverse associations between antibody titers and four distinct amino acid metabolic pathways: (1) biosynthesis of phenylalanine, tyrosine, and tryptophan; (2) biosynthesis of valine, leucine, and isoleucine; (3) phenylalanine metabolism; and (4) degradation of valine, leucine, and isoleucine. Additionally, an association between the synthesis and degradation pathways of ketone bodies was evident. In conclusion, we identified different metabolic pathways that underlie the diverse humoral responses triggered by COVID-19 mRNA vaccines during pregnancy. Our data hold significant implications for refining COVID-19 vaccination approaches in expectant mothers. Key messages: Anti-SARS-CoV-2 antibody titers decline as the number of days since COVID-19 vaccination increases. Anti-SARS-CoV-2 antibody titers are inversely associated with acetate, a microbial-derived metabolite, and urea. Amino acid metabolism is significantly associated with SARS-CoV-2 antibody titers. [ABSTRACT FROM AUTHOR]

Background: International practice guidelines advocate for the use of anti-phospholipase A2 receptor (PLA2R) antibody testing to diagnose primary membranous nephropathy (pMN). This study aimed to clarify the current status of anti-PLA2R antibody testing in the diagnosis of pMN in Japan and to scrutinize the factors associated with the implementation of this antibody test. Methods: Utilizing a web-based questionnaire for nephrologists, responses were collected from 306 facilities and 427 nephrologists between November 2021 and December 2021. Preference for anti-PLA2R antibody testing was also investigated. Factors related to the experience of quantifying anti-PLA2R antibodies were estimated by generalized estimating equations using a robust analysis of variance with clusters of facilities of affiliation. Results: Of the 427 respondents, 140 (32.8%) had previous measurement experience at their current workplace and 165 (38.6%) had previous measurement experience overall. In pMN-suspected cases without contraindications to renal biopsy, 147 (34.4%) of the respondents opted to request anti-PLA2R antibody testing. The respondents' experience with anti-PLA2R antibody quantification at their current place of work was generally higher in university hospitals and increased with the annual number of kidney biopsies and the number of years since graduation. Conclusion: The results of this study suggest that a significant proportion of nephrologists in Japan have no experience in performing anti-PLA2R antibody assays, and that the assays may be hampered by the limited capabilities of the current workplace and the financial burden on facilities and patients. [ABSTRACT FROM AUTHOR]

Squalene-based adjuvant compositions that can provide effective induction of specific humoral immune response have been developed. Recombinant receptor-binding domain (RBD) of surface S-protein of SARS-CoV-2 was used to evaluate the properties of the composition. Immunization of mice with the developed squalene-based compositions in combination with RBD allows obtaining high titers of specific antibodies: from 105 to 2×106. The blood sera from immunized mice exhibit neutralizing activity against SARS-CoV-2 Delta variant (B.1.617.2) with a titer up to 1:2000. [ABSTRACT FROM AUTHOR]

Here we described an 18-year-old woman who were initially misdiagnosed as psychiatric disorders in a psychiatric institution. She was transferred to our neurological ward because of impaired consciousness. Neuronal antibody testing confirmed the diagnosis of anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis. Cerebral magnetic resonance imaging (MRI) revealed a concomitant disorder named reversible splenial lesion syndrome (RESLES). After administration of combined immunotherapy, the patient recovered completely 3 months after discharge. To our knowledge, co-occurrence of RESLES and anti-NMDAR encephalitis was only described in two patients with teratoma and we provide another case without teratoma. We highlight that anti-NMDAR antibodies can be added to the multiple causes of RESLES. It is therefore imperative for clinicians to detect anti-neuronal antibodies in patients with RESLES to avoid missed diagnosis. [ABSTRACT FROM AUTHOR]

Multiplexed lateral flow assays (LFAs) offer efficient on-site testing by simultaneously detecting multiple biomarkers from a single sample, reducing costs. In cancer diagnostics, where biomarkers can lack specificity, multiparameter detection provides more information at the point-of-care. Our research focuses on epithelial ovarian cancer (EOC), where STn-glycosylated forms of CA125 and CA15-3 antigens can better discriminate cancer from benign conditions. We have developed a dual-label LFA that detects both CA125-STn and CA15-3-STn within a single anti-STn antibody test line. This utilizes spectral separation of green (540 nm) and blue (450 nm) emitting erbium (NaYF4:Yb3+, Er3+)- and thulium (NaYF4: Yb3+, Tm3+)-doped upconverting nanoparticle (UCNP) reporters conjugated with antibodies against the protein epitopes in CA125 or CA15-3. This technology allows the simultaneous detection of different antigen variants from a single test line. The developed proof-of-concept dual-label LFA was able to distinguish between the ascites fluid samples from diagnosed ovarian cancer patients (n = 10) and liver cirrhosis ascites fluid samples (n = 3) used as a negative control. The analytical sensitivity of CA125-STn for the dual-label LFA was 1.8 U/ml in buffer and 3.6 U/ml in ascites fluid matrix. Here we demonstrate a novel approach of spectrally separated measurement of STn-glycosylated forms of two different cancer-associated protein biomarkers by using UCNP reporter technology. [ABSTRACT FROM AUTHOR]

Crimean-Congo hemorrhagic fever virus (CCHFV) can cause severe human disease and is considered a WHO priority pathogen due to the lack of efficacious vaccines and antivirals. A CCHF virus replicon particle (VRP) has previously shown protective efficacy in a lethal Ifnar-/- mouse model when administered as a single dose at least 3 days prior to challenge. Here, we determine that non-specific immune responses are not sufficient to confer short-term protection, since Lassa virus VRP vaccination 3 days prior to CCHFV challenge was not protective. We also investigate how CCHF VRP vaccination confers protective efficacy by examining viral kinetics, histopathology, clinical analytes and immunity early after challenge (3 and 6 days post infection) and compare to unvaccinated controls. We characterize how these effects differ based on vaccination period and correspond to previously reported CCHF VRP-mediated protection. Vaccinating Ifnar-/- mice with CCHF VRP 28, 14, 7, or 3 days prior to challenge, all known to confer complete protection, significantly reduced CCHFV viral load, mucosal shedding, and markers of clinical disease, with greater reductions associated with longer vaccination periods. Interestingly, there were no significant differences in innate immune responses, T cell activation, or antibody titers after challenge between groups of mice vaccinated a week or more before challenge, but higher anti-NP antibody avidity and effector function (ADCD) were positively associated with longer vaccination periods. These findings support the importance of antibody-mediated responses in VRP vaccine-mediated protection against CCHFV infection. [ABSTRACT FROM AUTHOR]

Mosaic HIV-1 vaccines have been shown to elicit robust humoral and cellular immune responses in people living with HIV-1 (PLWH), that had started antiretroviral therapy (ART) during acute infection. We evaluated the safety and immunogenicity of 2 mosaic vaccine regimens in virologically suppressed individuals that had initiated ART during the chronic phase of infection, exemplifying the majority of PLWH. In this double-blind, placebo-controlled phase 1 trial (IPCAVD013/HTX1002) 25 ART-suppressed PLWH were randomized to receive Ad26.Mos4.HIV/MVA-Mosaic (Ad26/MVA) (n = 10) or Ad26.Mos4.HIV/Ad26.Mos4.HIV plus adjuvanted gp140 protein (Ad26/Ad26+gp140) (n = 9) or placebo (n = 6). Primary endpoints included safety and tolerability and secondary endpoints included HIV-specific binding and neutralizing antibody titers and HIV-specific T cell responses. Both vaccine regimens were well tolerated with pain/tenderness at the injection site and fatigue, myalgia/chills and headache as the most commonly reported solicited local and grade 3 systemic adverse events, respectively. In the Ad26/Ad26+gp140 group, Env-specific IFN-γ T cell responses showed a median 12-fold increase while responses to Gag and Pol increased 1.8 and 2.4-fold, respectively. The breadth of T cell responses to individual peptide subpools increased from 11.0 pre-vaccination to 26.0 in the Ad26/Ad26+gp140 group and from 10.0 to 14.5 in the Ad26/MVA group. Ad26/Ad26+gp140 vaccination increased binding antibody titers against vaccine-matched clade C Env 5.5-fold as well as augmented neutralizing antibody titers against Clade C pseudovirus by 7.2-fold. Both vaccine regimens were immunogenic, while the addition of the protein boost resulted in additional T cell and augmented binding and neutralizing antibody titers. These data suggest that the Ad26/Ad26+gp140 regimen should be tested further. [ABSTRACT FROM AUTHOR]

Antigenic characterization of newly emerging SARS-CoV-2 variants is important to assess their immune escape and judge the need for future vaccine updates. To bridge data obtained from animal sera with human sera, we analyzed neutralizing antibody titers in human and hamster single infection sera in a highly controlled setting using the same authentic virus neutralization assay performed in one laboratory. Using a Bayesian framework, we found that titer fold changes in hamster sera corresponded well to human sera and that hamster sera generally exhibited higher reactivity. [ABSTRACT FROM AUTHOR]

The Omicron variant is associated with increased transmissibility, but evidence about the impact of Omicron in seropositivity of children is limited. This study aims to evaluate SARS-CoV-2 seroprevalence in children during the different variants' subperiods. A prospective multicenter seroprevalence study was conducted in 7 University public hospitals in Greece from November 2021 to August 2022 (3 subperiods: November 2021-February 2022, March 2022-May 2022, June 2022-August 2022). Children from different age groups, admitted to the hospital or examined in outpatient clinics for reasons other than COVID-19 were enrolled. Neutralizing antibodies (Nabs), anti-Spike (anti-S) and anti-nucleocapsid (anti-N) SARS-CoV-2 IgG in serum were evaluated. A total of 2127 children (males:57,2%; median age:4,8years) were enrolled. Anti-N IgG seropositivity increased from 17,8% in the first sub-period to 40,7% in the second sub-period and then decreased in the third sub-period (36,7%). Anti-S IgG seropositivity appeared to have an increasing trend over the study period, starting from 34,8% and reaching 80,7%. Children aged 1–4 years old have significantly higher anti-N IgG titers compared to children aged 0–1 years old (p < 0,001). Infants have significantly lower anti-S IgG titers compared to all other age groups (p < 0,001). Immunocompromised children and infants have the lowest seropositivity for NAbs. Conclusions During the Omicron period, seropositivity significantly increased, as a result of higher transmissibility. Neonates and infants have lower antibody titers compared to other age groups, while young children aged 1–4 years old present higher antibody titers, suggesting that this age group may mount a higher antibody response. Continuous surveillance seroprevalence studies are needed in children, in order to identify the true extent of SARS-CoV-2 and guide the planning of adequate public health measures. [ABSTRACT FROM AUTHOR]

Background: Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) is an idiopathic central nervous system (CNS) demyelinating disease gaining recognition with wider availability of cell-based assay (CBA) testing and recently published diagnostic criteria. However, uncertainty remains regarding the interpretation of antibody titers, particularly cerebrospinal fluid (CSF) MOG antibody titers. Methods: All MOG IgG CBA results performed by the provincial MitogenDx laboratory in Alberta from July 2017 to July 2023 were retrieved. Chart review was performed in patients with both serum and CSF testing and ≥ 1 positive MOG antibody result. Demographics, antibody titers, clinical and imaging features, treatment, and diagnosis were analyzed based on serum/CSF status. Results: Among 4494 MOG CBA assays, there were 413 CSF samples in 402 patients, and 268 patients had at least one associated serum sample. Mean time between CSF and serum testing was 20.9 days (range 0–870 days), most with testing within 30 days. Five of the 268 patients had serum positive/CSF positive MOG antibodies, 4 with acute disseminated encephalomyelitis and 1 with longitudinally extensive transverse myelitis. Twenty-three patients had serum positive/CSF negative MOG and 13/23 with optic neuritis. CSF MOG antibody positive patients were younger, and more likely to remain MOG seropositive versus CSF negative patients. No seronegative patient had MOG antibodies in CSF. Conclusions: In province-wide testing, CSF MOG antibodies were rare, only in MOG seropositive patients and none with optic neuritis. Our study does not support a clear role for CSF MOG antibody testing in the majority of patients, although further study is required. [ABSTRACT FROM AUTHOR]

Naturally circulating antibodies could dramatically change the activity of immunogens. In some cases, cross-interference between antibodies led to the loss of their opsonizing ability. Therefore, the study of antibody repertoire in blood sera of healthy donors is helpful for the development of vaccines and diagnostic kits. Levels of antibodies to fragments of biologically significant glucosamine and galactosamine polysaccharides and their N-acetylated derivatives were first studied in blood sera of 34 healthy donors using six biotinylated carbohydrate ligands. The highest titer of antibodies was found to poly-β-(1→6)-N-acetylglucosamine (PNAG), including its fully de-N-acetylated fragment. High antibody titers to the galactosaminoglycan (GG) fragments were also detected. For both PNAG and GG, the level of antibodies to N-acetylated ligands was higher than to the ligands with free amino groups. A correlation between the antibody titers for the respective N-acetylated and N-deacetylated forms was observed, which may suggest a cross interaction. No significant amounts of the antibodies to the chitooligosaccharides were detected. The results obtained will help to rationally plan further immunological studies aimed at the development of new vaccines and diagnostic kits. [ABSTRACT FROM AUTHOR]

This study was conducted to evaluate the effects of different doses of selenium (Se) from Sel-Plex© (selenium-enriched Saccharomyces cerevisiae yeast) supplement on the antioxidant status, the antibody titers against the foot-and-mouth disease virus, and the expression of interleukin-2 (IL-2) and interferon-γ (IFN-γ) genes in ewes during the hot season. Six ewes were kept at 25 °C and received basal diet (the negative control group), and 24 ewes were kept at 38 °C for 5 h per day and received no supplement (the positive control), 0.15, 0.30, and 0.45 mg Se/kg. Ewes in the positive control had higher (P<0.001) liver enzyme activity, malondialdehyde (MDA), and cortisol levels, and lower antibody titer than the negative control. The liver enzymes' lowest (P<0.001) activities were observed in ewes receiving 0.30 and 0.45 mg Se/kg. Ewes receiving 0.30 and 0.45 mg Se/kg had lower MDA levels than other treatments. Ewes receiving 0.30 and 0.45 mg Se/kg had higher (P<0.001) total antioxidant capacity levels than those receiving 0.15 mg Se/kg and the positive control. Se-supplemented groups had lower (P<0.001) relative expression of IL-2 and higher (P<0.04) expression of IFN-γ than the positive control. The antibody titer was the same in the positive control and the group receiving 0.15 mg Se/kg. Ewes fed a diet with 0.30 and 0.45 mg Se/kg had higher (P<0.011) antibody titer than the positive control. The Se supplementation can reverse the decrease of antioxidant capacity and immune function caused by heat stress, and 0.3 mg Se/kg from Sel-Plex©is the best dose. [ABSTRACT FROM AUTHOR]

Post-acute sequelae of COVID-19 (PASC) or the continuation of COVID-19 (Coronavirus disease 2019) symptoms past 12 weeks may affect as many as 30% of people recovering from a SARS-CoV-2 (severe acute respiratory coronavirus 2) infection. The mechanisms regulating the development of PASC are currently not known; however, hypotheses include virus reservoirs, pre-existing conditions, microblood clots, immune dysregulation, as well as poor antibody responses. Importantly, virus neutralizing antibodies are essential for COVID-19 recovery and protection from reinfection but there is currently limited information on these immune regulators and associated cytokines in PASC patients. Understanding the key drivers of general and specific symptoms associated with Long COVID and the presence of virus neutralizing antibodies in PASC will aid in the development of therapeutics, diagnostics, and vaccines which currently do not exist. We designed a cross-sectional study to investigate systemic antibody and cytokine responses during COVID-19 recovery and PASC. In total, 195 participants were recruited in one of four groups: (1) Those who never had COVID-19 (No COVID); (2) Those in acute COVID-19 recovery (Acute Recovery) (4–12 weeks post infection); (3) Those who recovered from COVID-19 (Recovered) (+ 12 weeks from infection); and (4) those who had PASC (PASC) (+ 12 weeks from infection). Participants completed a questionnaire on health history, sex, gender, demographics, experiences with COVID-19 acute and COVID-19 recovery/continuing symptoms. Serum samples collected were evaluated for antibody binding to viral proteins, virus neutralizing antibody titers, and serum cytokine levels using Ella SimplePlex Immunoassay™ panels. We found participants with PASC reported more pre-existing conditions (e.g. such as hypertension, asthma, and obesity), and PASC symptoms (e.g. fatigue, brain fog, headaches, and shortness of breath) following COVID-19 than COVID-19 Recovered individuals. Importantly, we found PASC individuals to have significantly decreased levels of neutralizing antibodies toward both SARS-CoV-2 and the Omicron BA.1 variant. Sex analysis indicated that female PASC study participants had sustained antibody levels as well as levels of the inflammatory cytokines GM-CSF and ANG-2 over time following COVID-19. Our study reports people experiencing PASC had lower levels of virus neutralizing antibodies; however, the results are limited by the collection time post-COVID-19 and post-vaccination. Moreover, we found females experiencing PASC had sustained levels of GM-CSF and ANG-2. With lower levels of virus neutralizing antibodies, this data suggests that PASC individuals not only have had a suboptimal antibody response during acute SARS-CoV-2 infection but may also have increased susceptibility to subsequent infections which may exacerbate or prolong current PASC illnesses. We also provide evidence suggesting GM-CSF and ANG-2 to play a role in the sex-bias of PASC. Taken together, our findings maybe important for understanding immune molecular drivers of PASC and PASC subgroups. [ABSTRACT FROM AUTHOR]

In this study, a DNA vaccine was designed based on the aopB gene of type III secretory system of Aeromonas hydrophila using the eukaryotic pCDNA3.1 expression system. Produced DNA vaccine was encapsulated with synthetic polylactic-co-glycolic acid (PLGA) nanoparticles. After evaluating the efficiency and quality of nanoencapsulation, 270 common carp (18.3 ± 2.4 g) were divided into six equal groups in triplicates. Groups A and B (GA & GB) were orally vaccinated with pCDNA3.1-aopB plasmid with or without nanoencapsulation with PLGA, respectively. Groups C and D (GC & GD) were orally vaccinated with pCDNA3.1 plasmid with or without PLGA nanoencapsulation, respectively. Groups E and F received PLGA and PBS, respectively. The serum samples, head kidney, and intestine tissues were taken on days 0, 30, and 60 of the experiment. Hemato-immunological parameters and tissue distribution of the recombinant plasmid were assayed. All groups were also challenged with virulent A. hydrophila bacteria and the survival rate was recorded to determine the vaccination efficacy. The recombinant plasmid was detected in the anterior kidney and intestine of GA and GB. Anti-A. hydrophila antibody titer and the survival rate were significantly increased after the bacterial challenge in GA and GB compared to the control groups (P < 0.05). Nonspecific immune response markers were significantly increased in GA compared to the control group (P < 0.05). Hematological parameters show no significant difference in all groups and sampling time points (P > 0.05). Consequently, the constructed oral DNA vaccine based on the pCDNA3.1-aopB gene, encapsulated with PLGA, showed either sufficient protection or reliable immunogenicity against A. hydrophila infection in common carp. [ABSTRACT FROM AUTHOR]

Vibrio alginolyticus and Streptococcus agalactiae are important bacterial pathogens that yielded high losses in Nile tilapia in Egypt. The present study aimed to check the protective efficacy of inactivated whole-cell bivalent vaccines against these pathogens using incomplete Freund's adjuvant and Montanide™ IMS 1312 VG as adjuvants. The antibody titers have been determined at different weeks post-vaccination (WPV). Moreover, the protection levels against the challenged bacterial pathogens have also been examined in relation to the time-dependent protection at different WPV. The results revealed that serum antibodies were generated in all immunized fish at 1st WPV, peaked at 4th WPV, continued, and gradually decreased from 6th WPV to 14th WPV in all vaccinated groups. In addition, vaccines induced significantly higher protection of the immunized tilapia, manifested by higher survival rates. We noticed that the antibody levels and survival rates of the vaccinated fish by a vaccine adjuvanted by Montanide™ IMS 1312 VG were higher than those produced by a vaccine adjuvanted by incomplete Freund's adjuvant at different time points. Moreover, no external clinical signs, visceral adhesions, or internal lesions were recorded in the vaccinated tilapia, demonstrating the safety of the formulated vaccines. According to the aforementioned findings, we could suggest that the prepared bivalent vaccines, using the two adjuvant types, are safe and highly protective and could be utilized as promising candidate vaccines to increase the resistance of Nile tilapia against V. alginolyticus and S. agalactiae infections. Moreover, Montanide™ IMS 1312 VG enhanced the immuno-protectivity and exhibited optimum immune response and earlier protection compared to the vaccine adjuvanted by incomplete Freund's adjuvant, demonstrating its added value during the preparation of tilapia vaccines. [ABSTRACT FROM AUTHOR]

Background: For patients with neuronal surface antibody-associated autoimmune encephalitis (NSAE) whose clinical symptoms gradually improve, the recommended course of immunotherapy in China is about 6 months. We aim to explore the relationship between persistent antibody positivity when immunotherapy is discontinued at 6 months and subsequent relapse. Methods: Prospective inclusion of NSAE patients with clinical remission after 6-month immunotherapy. Their antibody titers and other clinical data were collected at onset and 6 months later. Based on the antibody test results at 6 months, patients were divided into an antibody-persistent group and an antibody-negative conversion group, and then the rate of relapse between the two groups were compared. Results: The study included 28 NSAE patients who were antibody-positive at diagnosis. After 6-month immunotherapy, there were 16 (57.1%) cases with persistent antibodies and 12 (42.9%) cases with antibody-negative conversion. In the acute phase of onset, seizures were more common in patients with persistent antibodies (87.5% vs. 50.0%, p = 0.044). During a mean follow-up period of 22 months, patients with persistent antibodies were more likely to experience relapse than those with antibody-negative conversion (37.5% vs. 0.0%, p = 0.024). There were no significant differences in antibody types, CSF findings, results of MRI and EEG, tumor combination, immunotherapy, and long-term outcome between the two groups (p > 0.05). Conclusions: For patients with persistent antibodies when immunotherapy is discontinued at 6 months, persistent antibody positivity was associated with a higher relapse rate. [ABSTRACT FROM AUTHOR]

Multiple sclerosis (MS) is an autoimmune neurodegenerative disease leading to inevitable disability and primarily affecting the young and middle-aged population. Recent studies have shown a direct correlation between the risk of MS development and Epstein–Barr virus (EBV) infection. Analysis of the titer of EBV-specific antibodies among patients with MS and healthy donors among Russian population confirmed that MS is characterized by an increased level of serum IgG binding EBNA-1 (EBV nuclear antigen 1). The number of patients with elevated levels of EBNA-1-specific antibodies does not differ statistically significantly between two groups with diametrically opposite courses of MS: benign MS or highly active MS. It can be assumed that the primary link between EBV and the development of MS is restricted to the initiation of the disease and does not impact its severity. [ABSTRACT FROM AUTHOR]

Background and Objective: During the COVID-19 pandemic, trials on convalescent plasma (ConvP) were performed without preceding dose-finding studies. This study aimed to assess potential protective dosing regimens by constructing a population pharmacokinetic (popPK) model describing anti-SARS-CoV-2 antibody titers following the administration of ConvP or hyperimmune globulins (COVIg). Methods: Immunocompromised patients, testing negative for anti-SARS-CoV-2 spike antibodies despite vaccination, received a range of anti-SARS-CoV-2 antibodies in the form of COVIg or ConvP infusion. The popPK analysis was performed using NONMEM v7.4. Monte Carlo simulations were performed to assess potential COVIg and ConvP dosing regimens for prevention of COVID-19. Results: Forty-four patients were enrolled, and data from 42 were used for constructing the popPK model. A two-compartment elimination model with mixed residual error best described the Nab-titers after administration. Inter-individual variation was associated to CL (44.3%), V1 (27.3%), and V2 (29.2%). Lean body weight and type of treatment (ConvP/COVIg) were associated with V1 and V2, respectively. Median elimination half-life was 20 days (interquartile range: 17–25 days). Simulations demonstrated that even monthly infusions of 600 mL of the ConvP or COVIg used in this trial would not achieve potentially protective serum antibody titers for > 90% of the time. However, as a result of hybrid immunity and/or repeated vaccination, plasma donors with extremely high antibody titers are now readily available, and a > 90% target attainment should be possible. Conclusion: The results of this study may inform future intervention studies on the prophylactic and therapeutic use of antiviral antibodies in the form of ConvP or COVIg. Clinical trial registration number: NL9379 (The Netherlands Trial Register). [ABSTRACT FROM AUTHOR]

To evaluate the antibody response following the initial four doses of mRNA vaccines (BNT162b2 or mRNA-1273) in SARS-CoV-2-naïve healthy adults and investigate factors influencing antibody titer increases, this prospective cohort study was conducted in Japan from March 2021. The study included participants who received either the 1st and 2nd doses (n = 467), 3rd dose (n = 157), or 4th dose (n = 89). Blood samples were collected before and up to 6 months after each dose, and anti-receptor-binding domain antibody levels were measured. Multivariate analysis (usin multiple linear regression or linear mixed models) revealed several factors significantly associated with higher post-vaccination antibody levels, including mRNA-1273 vaccine (after the 1st and 2nd dose), male gender (after the 3rd and 4th doses), younger age (after the 1st and 2nd dose), non-smoking status (after the 2nd dose), non-use of immunosuppressive agents (after the 1st dose), higher pre-vaccination antibody titers (after the 2nd, 3rd, and 4th doses), and higher post-vaccination fever (after the 2nd and 4th doses). Furthermore, longer intervals since the last dose were significantly associated with higher antibody levels after the 3rd and 4th doses. These findings provide valuable insights for optimizing vaccination strategies. [ABSTRACT FROM AUTHOR]

The ongoing vaccination efforts and exposure to endemic and emerging coronaviruses can shape the population's immunity against this group of viruses. In this study, we investigated neutralizing immunity against endemic and emerging coronaviruses in 200 Tanzanian frontline healthcare workers (HCWs). Despite low vaccination rates (19.5%), we found a high SARS-CoV-2 seroprevalence (94.0%), indicating high exposure in these HCWs. Next, we determined the neutralization capacity of antisera against human coronavirus NL63, and 229E, SARS-CoV-1, MERS-CoV and SARS-CoV-2 (including Omicron subvariants: BA.1, BQ.1.1 and XBB.1.5) using pseudovirus neutralization assay. We observed a broad range of neutralizing activity in HCWs, but no neutralization activity detected against MERS-CoV. We also observed a strong correlation between neutralizing antibody titers for SARS-CoV-2 and SARS-CoV-1, but not between other coronaviruses. Cross-neutralization titers against the newer Omicron subvariants, BQ.1.1 and XBB.1.5, was significantly reduced compared to BA.1 and BA.2 subvariants. On the other hand, the exposed vaccinated HCWs showed relatively higher median cross-neutralization titers against both the newer Omicron subvariants and SARS-CoV-1, but did not reach statistical significance. In summary, our findings suggest a broad range of neutralizing potency against coronaviruses in Tanzanian HCWs with detectable neutralizing immunity against SARS-CoV-1 resulting from SARS-CoV-2 exposure. [ABSTRACT FROM AUTHOR]

Current work has been designed to investigate the immunomodulatory efficacy with particular reference to humoral, cell-mediated and cytokine-modulating potential of hot aqueous extract of Neolamarckia cadamba (HAENC) fruits in Wistar albino rats. The effect of different concentrations of HAENC fruits over cell-mediated immune response was assessed using six groups (Gp-I as control, Gp-II with 20 µg/mL, Gp-III with 50 µg/mL, Gp-IV with 100 µg/mL, Gp-V with 250 µg/mL, and Gp-VI with 500 µg/mL) of Wistar albino rats having six animals in each. The amount of tumor necrosis factor-α (TNF-α) and interleukin (IL)-10 was measured by sandwich ELISA with different concentrations of HAENC (50–500 µg/mL) in splenocyte culture supernatant and their expression was determined by qRT-PCR Humoral immune response was determined by measuring the serum antibody titer of Wistar albino rats against Salmonella typhimurium 'O' antigen using four groups containing six animals each (Gp-I as control, Gp II, III & IV were respectively fed orally with 125, 250, and 500 mg/Kg body weight using HAENC fruits). LC–MS analysis suggested the presence of cadambine, chlorogenic acid, cadambagenic acid, stearic acid, octadecanoic acid ethyl ether, and 7-hydroxy-5,2'-4'-trimethoxyflavonon in the extract based on their m/z ratio. The result suggested significant (p < 0.01) dose-dependent proliferation of Concanavalin A (Con A)-treated splenocytes, depicting cell-mediated immunostimulatory potential of HAENC fruits. A dose-dependent significant decrease (p < 0.01) was found in the amount of TNF-α and IL-10 was found to increase significantly (p < 0.01) as extract concentrations increased. TNF-α and IL-10 expressions were confirmed at the molecular level by qRT-PCR analysis of mRNA transcripts of TNF-α and IL-10 genes. Fold expression of TNF-α and IL-10 gene was 0.197 and 3.58 at 250 µg/mL, 0.02 and 20.11 at 500 µg/mL concentrations of HAENC respectively in comparison to control. Serum antibody titer was significantly increased (p < 0.01) in animals fed with different doses of HAENC fruits. The present study suggested the anti-inflammatory effect of HAENC fruits which also influences the networking of cytokines, implying that it may play a role in regulating the activity of the host's immune system and can serve as a potent herbal drug with immuno-stimulatory potential. [ABSTRACT FROM AUTHOR]

Background and purpose: Testing for antiphospholipid antibodies (aPL) is useful to determine the cause of ischemic stroke in young and female patients. However, the clinical relevance of aPL in older patients with ischemic stroke remains unclear. We aimed to explore the status and diagnostic value of initial aPL testing in all patients with acute ischemic stroke. Methods: We retrospectively analyzed patients with acute ischemic stroke who were consecutively hospitalized in our hospital between June 2012 and January 2022 and investigated the factors associated with performing aPL screening in real-world clinical practice. Furthermore, factors associated with initial aPL positivity were evaluated by comparing the demographic, etiological, and therapeutic characteristics. Results: Of 1209 patients, 287 (23.7%) were tested for aPL and 58 (20.2%) tested positive. Physicians tended to conduct aPL testing on female patients (P<0.001), younger patients (P<0.001), patients with fewer vascular risk factors (P<0.001), and multiple infarctions in the multivascular blood supply area (P<0.001). Multivariate logistic regression analysis showed that only stroke of other determined etiology type was a significant influencing factor for positive aPL results (OR 2.97, 95% CI 1.137, 7.774, P=0.026), adjusting for sex, age, and causes of stroke, etc. Conclusion: Approximately one-quarter of the patients with acute ischemic stroke were tested for aPL. Age, sex, number of vascular risk factors, and neuroimaging features affected the discretion in performing aPL testing. aPL testing may be appropriate in older patients with no identified cause of ischemic stroke and may provide additional diagnostic opportunities for acute ischemic stroke. [ABSTRACT FROM AUTHOR]

Introduction: Serological assays are alternative laboratory tools for the diagnosis of parasitic infections. The aim of this work was to evaluate the performance of the indirect fluorescent antibody test (IFAT) and Western blotting (WB) for the detection of IgG anti-Giardia antibodies in human sera. Methodology: Sera from individuals infected with Giardia duodenalis, other parasites or non-parasitized were selected for serological assays. Ninety-seven sera were tested by IFAT at 1:20 and 1:40 dilutions and of these, 40 samples were also analyzed by WB. Results: The sensitivity and specificity of the IFAT was 97% and 46.9% at 1:20 sera dilution, and 39.4% and 59.4% at 1:40 sera dilution. The low molecular weight polypeptides fractions of 25 kDa, 27–31 kDa and 45–55 kDa were the most frequently identified by the sera of individuals infected with G. duodenalis, along with low cross-reactivity, presenting an individual sensitivity of 42.8%, 50.0% and 57.1%, and specificity of 83.3%, 83.3% and 91.7%, respectively. The highest overall sensitivity of WB (85.7%) was based on the immunoreactivity of sera with at least one of those proteins. The concordance between the detection of G. duodenalis in feces by microscopy and the WB results was considered substantial (Kappa = 0.61). Conclusion: Constant exposure to Giardia infection throughout a lifetime can maintain high levels of specific antibodies in serum, even without active infection. Moreover, proteins found in intestinal amoebas may hinder the serological diagnosis of giardiasis in endemic areas due to cross-reactivity, which can be partially solved using Giardia low molecular weight proteins. [ABSTRACT FROM AUTHOR]

Purpose: Visceral leishmaniasis (VL) is a systemic and parasitic disease that is usually fatal if left untreated. VL is endemic in different parts of Iran and is caused mainly by Leishmania infantum. This study aimed to recognition immunoreactive proteins in amastigote-like and promastigote stages of L. infantum (Iranian strain) by antibodies present in the sera of VL patients. Methods: Total protein extract from amastigote-like and promastigote cells was separated by two-dimensional electrophoresis (2DE). To detect the immunoreactive proteins, 2DE immunoblotting method was performed using different pools of VL patients' sera. Results: Approximately 390 and 430 protein spots could be separated in 2DE profiles of L. infantum amastigote-like and promastigote stages, respectively. In immunoblotting method, approximately 295 and 135 immunoreactive proteins of amastigotes-like reacted with high antibody titer serum pool and low antibody titer serum pool, respectively. Approximately 120 and 85 immunoreactive proteins of promastigote extract were recognized using the high antibody titer sera pool and low antibody titer sera, respectively. Conclusion: The present study has recognized a number of antigenic diversity proteins based on the molecular weight and pH in amastigote-like and promastigote stages of L. infantum. These results provide us a new concept for further analysis development in the field of diagnosis biomarkers and vaccine targets. [ABSTRACT FROM AUTHOR]

Different syndromes are involved in human psittacosis (flu-like syndrome, atypical pneumonia up to lacrimal gland lymphoma). Diagnostic methods include serology, culture, and PCR. The rate of Chlamydia psittaci (Cp) positive tests among exposed workers is still unknown. Our study aimed to assess the rate of positive tests among workers who have contact with carrier birds in natural reserves from Buenos Aires, Argentina. Secondary aims were to analyze risk factors linked to these outcomes and the occurrence of signs that suggest psittacosis. Nasopharyngeal swabs and serum pairs were collected from employees who had interacted with confirmed carrier birds. Those with detectable DNA of Cp and/or anti-Chlamydia spp. antibody baseline titer ≥ 160 mUI/ml, or at least quadruplicating, were considered positive. Activities performed with or near birds, personal protective equipment use, and previous chronic conditions were assessed. Possible Cp-related pathologies were evaluated during follow-up. A total of 63 exposed workers (71.4% men) with a median age of 35.7 years (IQR 26–39) were evaluated to detect 28.6% positives. Respiratory chronic conditions were the unique factor associated with positive tests (OR 5.2 [1.5–18.5] p <.05). Surprisingly, about a third of the workers resulted positive and all responded to medical treatment, none developing an acute atypical pneumonia syndrome associated with classical presentation of psittacosis. Active testing for early diagnosis and proper treatment in zoological workers exposed to carrier or potentially carrier birds is strongly suggested as part of zoonotic diseases preventive measures. [ABSTRACT FROM AUTHOR]