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Background and Objectives: Serological HTLV-1/2 screening is mandatory for blood donor candidates in Brazil. Our objective was to analyse HTLV test results in blood donors submitted for screening and confirmatory assays in a Brazilian blood bank., Materials and Methods: Retrospective analysis (2017-2022) results of chemiluminescence immunoassays and confirmatory tests for HTLV-1/2 in reactive donors were performed. During the analysed period, three sets of assays were used: (1) Architect rHTLV-I/II + HTLV Blot 2.4 (Western blot [WB]); (2) Alinity s HTLV I/II Reagent Kit + INNO-line immunoassay (LIA) HTLV I/II Score (LIA); (3) Alinity + WB., Results: The analysed period comprised a total of 1,557,333 donations. The mean percentage of HTLV reactive donors using the Architect assay was 0.14%. With the change to the Alinity assay, that percentage dropped 2.3-fold (0.06%). The reactivity rate in the confirmatory tests (1064 samples) ranged from 13.5% to 30.2%, whereas 58.3%-85.9% of samples were non-reactive. The highest rates of positive (30.2%) and indeterminate (11.5%) results were seen using LIA. Considering all analysed samples, those with signal/cut-off ratio (S/CO) >50 were positive in confirmatory tests (positive predictive value, PPV = 100%), whereas samples with S/CO ≤6 are very unlikely to be truly positive (PPV = 0)., Conclusion: The use of the Alinity assay reduced the frequency of false-positive results. Confirmatory tests are important to identify true HTLV infection in blood donors, because more than 58% of initially reactive individuals are confirmed as seronegative. Categorizing S/CO values is useful for assessing the likelihood of true HTLV-1/2 infection., (© 2024 International Society of Blood Transfusion.)

Here, the antiviral activity of aminoadamantane derivatives were evaluated against SARS-CoV-2. The compounds exhibited low cytotoxicity to Vero, HEK293 and CALU-3 cells up to a concentration of 1,000 µM. The inhibitory concentration (IC 50 ) of aminoadamantane was 39.71 µM in Vero CCL-81 cells and the derivatives showed significantly lower IC 50 values, especially for compounds 3F4 (0.32 µM), 3F5 (0.44 µM) and 3E10 (1.28 µM). Additionally, derivatives 3F5 and 3E10 statistically reduced the fluorescence intensity of SARS-CoV-2 protein S from Vero cells at 10 µM. Transmission microscopy confirmed the antiviral activity of the compounds, which reduced cytopathic effects induced by the virus, such as vacuolization, cytoplasmic projections, and the presence of myelin figures derived from cellular activation in the face of infection. Additionally, it was possible to observe a reduction of viral particles adhered to the cell membrane and inside several viral factories, especially after treatment with 3F4. Moreover, although docking analysis showed favorable interactions in the catalytic site of Cathepsin L, the enzymatic activity of this enzyme was not inhibited significantly in vitro. The new derivatives displayed lower predicted toxicities than aminoadamantane, which was observed for either rat or mouse models. Lastly, in vivo antiviral assays of aminoadamantane derivatives in BALB/cJ mice after challenge with the mouse-adapted strain of SARS-CoV-2, corroborated the robust antiviral activity of 3F4 derivative, which was higher than aminoadamantane and its other derivatives. Therefore, aminoadamantane derivatives show potential broad-spectrum antiviral activity, which may contribute to COVID-19 treatment in the face of emerging and re-emerging SARS-CoV-2 variants of concern., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Background: Human T-lymphotropic virus 1 (HTLV-1) is associated with the development of several pathologies and chronic infection in humans. The inefficiency of the available treatments and the challenge in developing a protective vaccine highlight the need to produce effective immunotherapeutic tools. The HTLV-1 basic leucine zipper (bZIP) factor (HBZ) plays an important role in the HTLV-1 persistence, conferring a survival advantage to infected cells by reducing the HTLV-1 proteins expression, allowing infected cells to evade immune surveillance, and enhancing cell proliferation leading to increased proviral load., Methods: We have generated a recombinant Modified Virus Vaccinia Ankara (MVA-HBZ) and a plasmid DNA (pcDNA3.1(+)-HBZ) expressing a multiepitope protein based on peptides of HBZ to study the immunogenic potential of this viral-derived protein in BALB/c mice model. Mice were immunized in a prime-boost heterologous protocol and their splenocytes (T CD4 + and T CD8 + ) were immunophenotyped by flow cytometry and the humoral response was evaluated by ELISA using HBZ protein produced in prokaryotic vector as antigen., Results: T CD4 + and T CD8 + lymphocytes cells stimulated by HBZ-peptides (HBZ 42-50 and HBZ 157-176 ) showed polyfunctional double positive responses for TNF-α/IFN-γ, and TNF-α/IL-2. Moreover, T CD8 + cells presented a tendency in the activation of effector memory cells producing granzyme B (CD44 +High /CD62L -Low ), and the activation of Cytotoxic T Lymphocytes (CTLs) and cytotoxic responses in immunized mice were inferred through the production of granzyme B by effector memory T cells and the expression of CD107a by CD8 + T cells. The overall data is consistent with a directive and effector recall response, which may be able to operate actively in the elimination of HTLV-1-infected cells and, consequently, in the reduction of the proviral load. Sera from immunized mice, differently from those of control animals, showed IgG-anti-HBZ production by ELISA., Conclusions: Our results highlight the potential of the HBZ multiepitope protein expressed from plasmid DNA and a poxviral vector as candidates for therapeutic vaccine., (© 2023. The Author(s).)

Introduction and Methods: In this present work, coronavirus subfamilies and SARS-CoV-2 Variants of Concern (VOCs) were investigated for the presence of MHC-I immunodominant viral peptides using in silico and in vitro tools., Results: In our results, HLA-A*02 haplotype showed the highest number of immunodominant epitopes but with the lowest combined prediction score. Furthermore, a decrease in combined prediction score was observed for HLA-A*02-restricted epitopes when the original strain was compared to the VOCs, indicating that the mutations on the VOCs are promoting escape from HLA-A2-mediated antigen presentation, which characterizes a immune evasion process. Additionally, epitope signature analysis revealed major immunogenic peptide loss for structural (S) and non-structural (ORF8) proteins of VOCs in comparison to the Wuhan sequence., Discussion: These results may indicate that the antiviral CD8 + T-cell responses generated by original strains could not be sufficient for clearance of variants in either newly or reinfection with SARS-CoV-2. In contrast, N epitopes remain the most conserved and reactive peptides across SARS-CoV-2 VOCs. Overall, our data could contribute to the rational design and development of new vaccinal platforms to induce a broad cellular CD8 + T cell antiviral response, aiming at controlling viral transmission of future SARS-CoV-2 variants., 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 © 2023 Lopes-Ribeiro, Oliveira, Retes, Barbosa-Stancioli, da Fonseca, Tsuji and Coelho-dos-Reis.)

Background: Cell responses to different stress inducers are efficient mechanisms that prevent and fight the accumulation of harmful macromolecules in the cells and also reinforce the defenses of the host against pathogens. Vaccinia virus (VACV) is an enveloped, DNA virus, belonging to the Poxviridae family. Members of this family have evolved numerous strategies to manipulate host responses to stress controlling cell survival and enhancing their replicative success. In this study, we investigated the activation of the response signaling to malformed proteins (UPR) by the VACV virulent strain-Western Reserve (WR)-or the non-virulent strain-Modified Vaccinia Ankara (MVA)., Methods: Through RT-PCR RFLP and qPCR assays, we detected negative regulation of XBP1 mRNA processing in VACV-infected cells. On the other hand, through assays of reporter genes for the ATF6 component, we observed its translocation to the nucleus of infected cells and a robust increase in its transcriptional activity, which seems to be important for virus replication. WR strain single-cycle viral multiplication curves in ATF6α-knockout MEFs showed reduced viral yield., Results: We observed that VACV WR and MVA strains modulate the UPR pathway, triggering the expression of endoplasmic reticulum chaperones through ATF6α signaling while preventing IRE1α-XBP1 activation., Conclusions: The ATF6α sensor is robustly activated during infection while the IRE1α-XBP1 branch is down-regulated., (© 2023. The Author(s).)

The present study sought to search for the immunodominance related to the N-terminal, Central and C-terminal regions of HTLV-1 Tax using novel, cutting-edge peptide microarray analysis. In addition, in silico predictions were performed to verify the presence of nine amino acid peptides present along Tax restricted to the human leukocyte antigen (HLA)-A2.02*01 haplotype, as well as to verify the ability to induce pro-inflammatory and regulatory cytokines, such as IFN-γ and IL-4, respectively. Our results indicated abundant dose-dependent reactivity for HLA-A*02:01 in all regions (N-terminal, Central and C-terminal), but with specific hotspots. Furthermore, the results of fold-change over the Tax 11-19 reactivity obtained at lower concentrations of HLA-A*02:01 reveal that peptides from the three regions contain sequences that react 100 times more than Tax 11-19 . On the other hand, Tax 11-19 has similar or superior HLA-A*02:01 reactivity at higher concentrations of this haplotype. The in silico analysis showed a higher frequency of IFN-γ-inducing peptides in the N-terminal portion, while the C-terminal portion showed a higher frequency of IL-4 inducers. Taken together, these results shed light on the search for new Tax immunodominant epitopes, in addition to the canonic Tax 11-19 , for the rational design of immunomodulatory strategies for HTLV-1 chronic diseases.

Introduction: The present work sought to identify MHC-I-restricted peptide signatures for arbovirus using in silico and in vitro peptide microarray tools., Methods: First, an in-silico analysis of immunogenic epitopes restricted to four of the most prevalent human MHC class-I was performed by identification of MHC affinity score. For that, more than 10,000 peptide sequences from 5 Arbovirus and 8 different viral serotypes, namely Zika (ZIKV), Dengue (DENV serotypes 1-4), Chikungunya (CHIKV), Mayaro (MAYV) and Oropouche (OROV) viruses, in addition to YFV were analyzed. Haplotype HLA-A*02.01 was the dominant human MHC for all arboviruses. Over one thousand HLA-A2 immunogenic peptides were employed to build a comprehensive identity matrix. Intending to assess HLAA*02:01 reactivity of peptides in vitro, a peptide microarray was designed and generated using a dimeric protein containing HLA-A*02:01., Results: The comprehensive identity matrix allowed the identification of only three overlapping peptides between two or more flavivirus sequences, suggesting poor overlapping of virus-specific immunogenic peptides amongst arborviruses. Global analysis of the fluorescence intensity for peptide-HLA-A*02:01 binding indicated a dose-dependent effect in the array. Considering all assessed arboviruses, the number of DENV-derived peptides with HLA-A*02:01 reactivity was the highest. Furthermore, a lower number of YFV-17DD overlapping peptides presented reactivity when compared to non-overlapping peptides. In addition, the assessment of HLA-A*02:01-reactive peptides across virus polyproteins highlighted non-structural proteins as "hot-spots". Data analysis supported these findings showing the presence of major hydrophobic sites in the final segment of non-structural protein 1 throughout 2a (Ns2a) and in nonstructural proteins 2b (Ns2b), 4a (Ns4a) and 4b (Ns4b)., Discussion: To our knowledge, these results provide the most comprehensive and detailed snapshot of the immunodominant peptide signature for arbovirus with MHC-class I restriction, which may bring insight into the design of future virus-specific vaccines to arboviruses and for vaccination protocols in highly endemic areas., 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 Lopes-Ribeiro, Araujo, Oliveira, Teixeira, Ferreira, Lourenço, Dias, Teixeira, Retes, Lopes, Versiani, Barbosa-Stancioli, da Fonseca, Martins-Filho, Tsuji, Peruhype-Magalhães and Coelho-dos-Reis.)

Background: The inflammatory response plays a significant role in the outcome of coronavirus disease (COVID-19)., Methods: We investigated plasma cytokine and chemokine concentrations in non-infected (NI), asymptomatic severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2)-infected blood donors (AS), and patients with severe COVID-19 (SC)., Results: The SC group showed significantly higher levels of interleukin 6 (IL-6), IL-10, and CCL5 than the AS and NI groups. The SC and AS groups had considerably greater CXCL9 and CXCL10 concentrations than the NI group. Only NI and infected people showed separate clusters in the principal component analysis., Conclusions: SC, as well as AS was characterized by an inflammatory profile.

The feline immunodeficiency virus (FIV) is a retrovirus with global impact and distribution, affecting both domestic and wild cats. This virus can cause severe and progressive immunosuppression culminating in the death of felids. Since the discovery of FIV, only one vaccine has been commercially available. This vaccine has proven efficiency against FIV subtypes A and D, whereas subtype B (FIV-B), found in multiple continents, is not currently preventable by vaccination. We, therefore, developed and evaluated a vaccine prototype against FIV-B using the recombinant viral vector modified vaccinia virus Ankara (MVA) expressing the variable region V1-V3 of the FIV-B envelope protein. We conducted preclinical tests in immunized mice (C57BL/6) using a prime-boost protocol with a 21 day interval and evaluated cellular and humoral responses as well the vaccine viability after lyophilization and storage. The animals immunized with the recombinant MVA/FIV virus developed specific splenocyte proliferation when stimulated with designed peptides. We also detected cellular and humoral immunity activation with IFN-y and antibody production. The data obtained in this study support further development of this immunogen and testing in cats.

The SARS-CoV-2 virus has infected and killed millions of people, but little is known about the risk factors that lead to the development of severe, mild or asymptomatic conditions after infection. The individual immune response and the balance of cytokines and chemokines have been shown to be important for the prognosis of patients. Additionally, it is essential to understand how the production of specific antibodies with viral neutralizing capacity is established. In this context, this study aimed to identify positive individuals for IgG anti-SARS-CoV-2 in a large population of blood donors (n = 7837) to establish their immune response profile and to evaluate its viral neutralization capacity. The prevalence found for IgG anti-SARS-CoV-2 was 5.6% (n = 441), with male blood donors (61.9%) being more prevalent among the positive ones. The results showed that positive individuals for IgG anti-SARS-CoV-2 have high serum concentrations of chemokines, TNF, IFN-γ and IL-10. The analyses showed that the positivity index for IgG anti-SARS-CoV-2 is associated with the neutralizing capacity of the antibodies, which, in turn, is significantly related to lower serum concentrations of CCL5 and CXCL10. The results allow us to hypothesize that the development and maintenance of IgG anti-SARS-CoV-2 antibodies in infected individuals occurs in a pro-inflammatory microenvironment well regulated by IL-10 with great capacity for recruiting cells from the innate and adaptive immune systems., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

A multi-epitope protein expressed in a prokaryotic system, including epitopes of Env, Gag, and Tax proteins of both HTLV-1 and HTLV-2 was characterized for HTLV-1/2 serological screening. This tool can contribute to support the implementation of public policies to reduce HTLV-1/2 transmission in Brazil, the country with the highest absolute numbers of HTLV-1/2 infected individuals. The chimeric protein was tested in EIA using serum/plasma of HTLV-infected individuals and non-infected ones from four Brazilian states, including the North and Northeast regions (that present high prevalence of HTLV-1/2) and Southeast region (that presents intermediate prevalence rates) depicting different epidemiological context of HTLV-1/2 infection in our country. We enrolled samples from Pará ( n = 114), Maranhão ( n = 153), Minas Gerais ( n = 225) and São Paulo ( n = 59) states; they are from blood donors' candidates (Pará and Minas Gerais), pregnant women (Maranhão) and HIV+/high risk for sexually transmitted infection (STI; São Paulo). Among the HTLV-1/2 positive sera, there were co-infections with viral (HTLV-1 + HTLV-2, HIV, HCV, and HBV), bacterial ( Treponema pallidum ) and parasitic ( Trypanosoma cruzi, Schistosma mansoni, Strongyloides stercoralis, Entamoeba coli, E. histolytica , and Endolimax nana ) pathogens related to HTLV-1/2 co-morbidities that can contribute to inconclusive diagnostic results. Sera positive for HIV were included among the HTLV-1/2 negative samples. Considering both HTLV-1 and HTLV-2-infected samples from all states and different groups (blood donor candidates, pregnant women, and individuals with high risk for STI), mono or co-infected and HTLV-/HIV+, the test specificity ranged from 90.09 to 95.19% and the sensitivity from 82.41 to 92.36% with high accuracy (ROC AUC = 0.9552). This multi-epitope protein showed great potential to be used in serological screening of HTLV-1 and HTLV-2 in different platforms, even taking into account the great regional variation and different profile of HTLV-1 and HTLV-2 mono or co-infected individuals., 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 Franco, Rocha, Cox, Daian e Silva, da Silveira e Santos, Martins, Romanelli, Ishak, Vallinoto, Bomfim, Caterino-de-Araujo, Coelho-dos-Reis, da Fonseca and Barbosa-Stancioli.)

Klebsiella variicola, a member of Klebsiella pneumoniae complex, is found to infect plants, insects, and animals and is considered an emerging pathogen in humans. While antibiotic resistance is often prevalent among K. variicola isolates from humans, this has not been thoroughly investigated in isolates from nonhuman sources. Prior evidence suggests that K. variicola can be transmitted between agricultural products as well as between animals, and the use of antibiotics in agriculture has increased antibiotic resistance in other emerging pathogens. Furthermore, in animals that contain K. variicola as a normal member of the rumen microbiota, the same bacteria can also cause infections, such as clinical mastitis in dairy cows. Here, we describe K. variicola UFMG-H9 and UFMG-H10, both isolated from the urine of healthy Gyr heifers. These two genomes represent the first isolates from the urine of cattle and exhibit greater similarity with strains from the human urinary tract than isolates from bovine fecal or milk samples. Unique to the UFMG-H9 genome is the presence of flagellar genes, the first such observation for K. variicola . Neither of the sampled animals had symptoms associated with K. variicola infection, even though genes associated with virulence and antibiotic resistance were identified in both strains. Both strains were resistant to amoxicillin, erythromycin, and vancomycin, and UFMG-H10 is resistant to fosfomycin. The observed resistances emphasize the concern regarding the emergence of this species as a human pathogen given its circulation in healthy livestock animals. IMPORTANCE Klebsiella variicola is an opportunistic pathogen in humans. It also has been associated with bovine mastitis, which can have significant economic effects. While numerous isolates have been sequenced from human infections, only 12 have been sequenced from cattle (fecal and milk samples) to date. Recently, we discovered the presence of K. variicola in the urine of two healthy heifers, the first identification of K. variicola in the bovine urinary tract and the first confirmed K. variicola isolate encoding for flagella-mediated motility. Here, we present the genome sequences and analysis of these isolates. The bovine urinary genomes are more similar to isolates from the human urinary tract than they are to other isolates from cattle, suggesting niche specialization. The presence of antibiotic resistance genes is concerning, as prior studies have found transmission between animals. These findings are important to understand the circulation of K. variicola in healthy livestock animals.

During epidemics, data from different sources can provide information on varying aspects of the epidemic process. Serology-based epidemiologic surveys could be used to compose a consistent epidemic scenario. We assessed the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG in serum samples collected from 7,837 blood donors in 7 cities of Brazil during March-December 2020. Based on our results, we propose a modification in a compartmental model that uses reported number of SARS-CoV-2 cases and serology results from blood donors as inputs and delivers estimates of hidden variables, such as daily values of SARS-CoV-2 transmission rates and cumulative incidence rate of reported and unreported SARS-CoV-2 cases. We concluded that the information about cumulative incidence of a disease in a city's population can be obtained by testing serum samples collected from blood donors. Our proposed method also can be extended to surveillance of other infectious diseases.

The study of livestock microbiota has immediate benefits for animal health as well as mitigating food contamination and emerging pathogens. While prior research has indicated the gastrointestinal tract of cattle as the source for many zoonoses, including Shiga-toxin producing Escherichia coli and antibiotic resistant bacteria, the bovine urinary tract microbiota has yet to be thoroughly investigated. Here, we describe 5 E. coli and 4 Pseudomonas aeruginosa strains isolated from urine of dairy Gyr cattle. While both species are typically associated with urinary tract infections and mastitis, all of the animals sampled were healthy. The bovine urinary strains were compared to E. coli and P. aeruginosa isolates from other bovine samples as well as human urinary samples. While the bovine urinary E. coli isolates had genomic similarity to isolates from the gastrointestinal tract of cattle and other agricultural animals, the bovine urinary P. aeruginosa strains were most similar to human isolates suggesting niche adaptation rather than host adaptation. Examination of prophages harbored by these bovine isolates revealed similarity with prophages within distantly related E. coli and P. aeruginosa isolates from the human urinary tract. This suggests that related urinary phages may persist and/or be shared between mammals. Future studies of the bovine urinary microbiota are needed to ascertain if E. coli and P. aeruginosa are resident members of this niche and/or possible sources for emerging pathogens in humans., 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 Giannattasio-Ferraz, Ene, Gomes, Queiroz, Maskeri, Oliveira, Putonti and Barbosa-Stancioli.)

Prevalence of hepatitis C virus (HCV) is high in hemophilia A patients and the development of FVIII inhibitor is another challenge in the management of these individuals. The influence of HCV infection in the occurrence of inhibitors was investigated by the comparison of clinical and laboratory data from noninfected (NI, n = 96) and chronically HCV-infected (HCV, n = 58) hemophilia A patients. Concentrations of plasmatic cytokines (IL-2, IL-4, IL-6, IL-10, TNF, IFN-γ, and IL-17A) and chemokines (CCL2, CCL5, CXCL8, CXCL9, and CXCL10) were quantified from patients' samples. The results showed that older age, use of cryoprecipitate and fresh frozen plasma, and severe hemophilia were associated with HCV infection, whereas exclusive use of virus inactivated clotting factors was a protector factor to acquiring HCV infection. HCV infection was strongly associated with low levels of inhibitor (OR = 20.53, p < 0.001). Patients with a history of inhibitor (INB+) presented a mixed immune profile characterized by higher levels of pro-and anti-inflammatory cytokines than those without a history of inhibitor (INB-). The highest levels of CCL2 and CXCL8 were seen in HCV INB- , whereas CXCL9 and CXCL10 in HCV INB+ . Heatmap analysis of the set of cytokines and chemokines concentration distributed HCV patients into two distinct clusters, HCV INB+ and HCV INB- , both characterized by low concentrations of IL-4, while noninfected patients were grouped in a single block regardless of inhibitor development history (NI INB-/INB+ ). This finding suggests that the strong association between HCV infection and low levels of factor VIII inhibitors might be due to the modulation of the cytokine and chemokine network established by the antiviral response., (© 2021 Wiley Periodicals LLC.)

Corynebacterium phoceense is a Gram-positive species previously isolated from human urine. Although other species from the same genus have been associated with urinary tract infections, C. phoceense is currently believed to be a non-pathogenic member of the urogenital microbiota. Prior to our study, only two isolates were described in the literature, and very little is known about the species. Here, we describe C. phoceense UFMG-H7, the first strain of this species isolated from the urine of healthy cattle. The genome for this isolate was produced and compared to the two other publicly available C. phoceense as well as other Corynebacterium genome assemblies. Our in-depth genomic analysis identified four additional publicly available genome assemblies that are representatives of the species, also isolated from the human urogenital tract. Although none of the strains have been associated with symptoms or disease, numerous genes associated with virulence factors are encoded. In contrast to related Corynebacterium species and Corynebacterium species from the bovine vaginal tract, all C. phoceense strains examined code for the SpaD-type pili suggesting adherence is essential for its persistence within the urinary tract. As the other C. phoceense strains analysed were isolated from the human urogenital tract, our results suggest that this species may be specific to this niche.

An alarming disease caused by the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) named COVID-19 has emerged as an unprecedented public health problem and ignited a world health crisis. As opposed to what was believed at the beginning of the pandemic, the virus has not only spread but persevere causing secondary waves and challenging the concept of herd immunity against viral infections. While the majority of SARS-CoV-2-infected individuals may remain asymptomatic, a fraction of individuals may develop low to high-grade severity signs and symptoms of COVID-19. The disease is multifactorial and can progress quickly, leading to severe complications and even death in a few days. Therefore, understanding the pre-existing factors for disease development has never been so pressing. In this scenario, the insights on the mechanisms underlying disease allied to the immune response developed during the viral invasion could shed light on novel predictive factors and prognostic tools for COVID-19 management and interventions. A recent genome-wide association study (GWAS) revealed several molecules that significantly impacted critically ill COVID-19 patients, leading to the core mechanisms of COVID-19 pathogenesis. Considering these findings and the fact that ACE-2 polymorphisms alone cannot explain disease progress and severity, this review aims at summarizing the most important and recent findings of the research and expert consensus of possible cytokine-related polymorphisms existing in the differential expression of paramount immune molecules that could be crucial for providing guidelines for decision-making and appropriate clinical management of COVID-19., (Copyright © 2021. Published by Elsevier B.V.)

Introduction: We present a data analysis and review of recent studies regarding the laboratory diagnosis of human T-lymphotropic virus 1 and 2 (HTLV-1/2) infections in Brazil., Methods: Target populations, available diagnostic serological assays (screening and complementary tests), molecular assays (in-house), causes of false-positive and false-negative results, and flowcharts were analyzed., Results: A table presents the target populations, two diagnostic flowcharts (depending on laboratory infrastructure and study population), and recent research that may improve how HTLV-1/2 is diagnosed in Brazil., Conclusions: Our results support the implementation of public policies to reduce HTLV-1/2 transmission and its associated diseases.

Introduction: The response mediated by CD8 + T-cells in the context of infection and vaccination has been thoroughly investigated and represents one of the most important branches that allow for the development of immunity against intracellular pathogens and, thus, the establishment of robust antiviral responses. However, there is a lack of methods to assess antigen-specific CD8 + T-cells., Objective: Search for the ideal assays to assess the function of antigen-specific CD8 + T-cells., Methods: In the present study a chimeric HLA-A2:β2M:Ig fusion protein was produced, purified, and evaluated in functional CD8 + T-cell response studies using samples from Influenza A patients and humanized mice upon adenoviral vaccination., Results: The HLA-A2:β2M:Ig molecule, bound to immunodominant viral peptides by passive transfer, was able to induce robust antiviral CD8 + T-cell responses mediated by IFN-γ. The in vitro IFN-γ release assay using the chimeric HLA-A2:β2M:Ig fusion protein detected bona fide human CD8 + T-cells, demonstrating superior production of IFN-γ by human CD8 + T-cells induced by Influenza A immunodominant GILGFVFTL peptide. Removal of antigen-presenting cells and CD8 + T-cell enrichment improved significantly the IFN-γ production. The chimeric HLA-A2:β2M:Ig fusion protein also triggered HLA-A2-restricted CD8 + T-cell response in a humanized mouse model upon vaccination with adenovirus encoding HLA-A2-restricted HIV p24 antigen. The results strongly suggest the use of tailor-made assays for detecting HLA-A2-restricted CD8 + T-cell Responses in the Humanized Mouse Model., Conclusion: The chimeric HLA-A2:β2M:Ig fusion protein-based assays provided a sensitive tool that may be paramount to measure virus-specific CD8 + T-cell response in a range of viral infections of clinical relevance., (Copyright © 2021. Published by Elsevier B.V.)

While the gram-positive bacterium Vagococcus fluvialis has been isolated from the environment as well as fish, birds, and mammals, very little is known about the species. V. fluvialis is believed to be a probiotic in fishes. However, within mammals, it is more frequently isolated from infectious tissue, including on rare occasions human and livestock lesions. Prior to the study described here, V. fluvialis had never been found in healthy bovine animals. Here, we present the complete genomes of V. fluvialis UFMG-H6, UFMG-H6B, and UFMG-H7, novel strains isolated from urine samples from healthy bovine females. These are the first genomes of mammalian isolates and the first description of V. fluvialis from urine. The genomes did not encode for any known virulence genes, suggesting that they may be commensal members of the urine microbiota., (© The Author(s) 2020. Published by Oxford University Press on behalf of Genetics Society of America.)

Porcine circovirus 2 (PCV2) infections are related to a number of syndromes and clinical manifestations, generally known as Porcine circovirus-associated diseases, which are related to losses in the swine industry. There are commercially available vaccines and new vaccines being tested, however, persistency of the PCV2 as an important pig pathogen, and the growing number of affected farms in different countries have suggested that there is room for vaccine improvement. In this study, we describe the construction and testing of a recombinant live vaccine based on a modified Vaccinia virus Ankara (MVA) vector expressing the PCV2b capsid protein (CAP). Using a two-dose homologous vaccination regimen, in mice, we demonstrated that the vaccine induced high titers of anti-PCV2 antibodies. The vaccine is stable upon lyophilization, and, together with the good immunogenicity potential observed, the results support further evaluation of the MVA-CAP vaccine in the target species.

The Flaviviridae virus family was named after the Yellow-fever virus, and the latin term flavi means "of golden color". Dengue, caused by Dengue virus (DENV), is one of the most important infectious diseases worldwide. A sensitive and differential diagnosis is crucial for patient management, especially due to the occurrence of serological cross-reactivity to other co-circulating flaviviruses. This became particularly important with the emergence of Zika virus (ZIKV) in areas were DENV seroprevalence was already high. We developed a sensitive and specific diagnostic test based on gold nanorods (GNR) functionalized with DENV proteins as nanosensors. These were able to detect as little as one picogram of anti-DENV monoclonal antibodies and highly diluted DENV-positive human sera. The nanosensors could differentiate DENV-positive sera from other flavivirus-infected patients, including ZIKV, and were even able to distinguish which DENV serotype infected individual patients. Readouts are obtained in ELISA-plate spectrophotometers without the need of specific devices.

Members of the Staphylococcus genus are known pathogens causing mastitis in dairy cows, which results in major economic losses. Here, we present Staphylococcus epidermidis UFMG-H7, Staphylococcus hominis UFMG-H7B, and Staphylococcus sciuri UFMG-H6, isolated from the urine of healthy purebred Gyr heifers., (Copyright © 2020 Giannattasio-Ferraz et al.)

Enterobacter asburiae is part of the Enterobacter cloacae complex, related to nosocomial opportunistic infections in humans. Here, we report the draft genome of E. asburiae strain UFMG-H9, an isolate from urine from a healthy Gyr heifer., (Copyright © 2020 Giannattasio-Ferraz et al.)

Enterococcus casseliflavus is a commensal bacterium present in the intestinal microbiota of different animals. Previous studies have found that strains isolated from livestock are often resistant to many different antibiotics. Here, we present three E. casseliflavus strains, UFMG-H7, UFMG-H8, and UFMG-H9, isolated from urine collected from healthy dairy heifers in Brazil., (Copyright © 2020 Giannattasio-Ferraz et al.)

Aeromonas caviae is an emerging pathogen in humans, causing intestinal infections. Here, we report Aeromonas caviae strain UFMG-H8, isolated from the urine of a healthy heifer (Gyr breed)., (Copyright © 2020 Giannattasio-Ferraz et al.)

Citrobacter freundii is a pathogen associated with antibiotic resistance and severe infections in humans. Here, we report the draft genome sequence of C. freundii strain UFMG-H9, an isolate from urine from a healthy Gyr heifer., (Copyright © 2020 Giannattasio-Ferraz et al.)

In some areas of Argentina endemic for human T-lymphotropic virus type 1 (HTLV-1), tropical spastic paraparesis is frequent in subjects who lack antibodies against the virus; however, the relevance of this seronegative status in the country has not been investigated. In neighboring countries, HTLV-1 seronegative status has been described in patients with different diseases; however, data regarding features of seronegative HTLV-1 carriers are scarce. We investigated the seronegative status in 124 relatives of 28 HTLV-1 infected subjects from an endemic area in Northwest Argentina. Blood samples and clinical/epidemiological data were collected. Human T-lymphotropic virus type 1 infection was diagnosed by serology and long terminal repeat (LTR) sequence, env and tax gene detection. IgG anti-Tax HTLV-1 antibody, tax gene sequence, and DNA proviral load were also evaluated. Seventy-five percent of the 124 relatives were negative for HTLV-1/2 antibodies; 35.5% were also negative by molecular assays and 64.5% were negative for HTLV-1 LTR and env sequences, but positive for two sequences of HTLV-1 tax gene. Also, 35.7% of these subjects had IgG anti-Tax antibodies. The seronegative HTLV-1 status was significantly associated with male gender, youth, and sensory symptoms/autonomic nervous system dysfunction. High rates of seronegative symptomatic and asymptomatic HTLV-1 carriers in Argentina are described. The evidence highlights that HTLV-1 prevalence may be underestimated worldwide. Larger cohort studies are required to assess disease outcome in these seronegative subjects. Also, the findings emphasize the limitations of ongoing screening assays for diagnosis and blood safety. Therefore, algorithms for HTLV-1 diagnosis should include not only serological but also molecular assays.

Describing the bovine vaginal microbiota is essential to better understand its physiology and its impact on health maintenance. Despite the economic importance of reproduction of these animals, bovine vaginal microbial community is still poorly described in comparison with rumen microbiome. Previous studies of our group described the vaginal microbiota of Nellore, an important Bos taurus indicus breed, using metagenomics. In order to better understand this microbiota, the present work aims to investigate another important breed, Gyr. Results have shown bacterial dominance over Archaea and Fungi was observed, with the most abundant bacterial phylum (Firmicutes) representing 40-50% of bacterial population, followed by Bacteroidetes, Proteobacteria, and Actinobacteria. The Fungi kingdom had the Mycosphaerella genus as its main representative, followed by Cladosporium. Archaea were observed at a very low abundance in all animals, with a high relative abundance of Methanobrevibacter genus. These results demonstrate a high microbial diversity on vaginal tract of Gyr, as demonstrated for Nellore and different from the previously described for other species. Our results indicate a great similarity between vaginal microbiota of Nellore and Gyr despite the differences in animal handling and genetic improvement. As observed for both breeds, individual variation is the largest source of microbial diversity between animals.

Senecavirus A (SVA) belonging to the family Picornaviridae, genus Senecavirus was incidentally isolated in 2002 from the PER.C6 (transformed foetal retinoblast) cell line. However, currently, this virus is associated with vesicular disease in swine and it has been reported in countries such as the United States of America, Canada, China, Thailand and Colombia. In Brazil, the SVA was firstly reported in 2015 in outbreaks of vesicular disease in swine, clinically indistinguishable of Foot-and-mouth disease, a contagious viral disease that generates substantial economic losses. In the present work, it was standardized a diagnostic tool for SVA based on RNA reverse transcriptase droplet digital PCR (RT-ddPCR) using one-step and two-step approaches. Analytical sensitivity and specificity were done in parallel with real-time PCR, RT-qPCR (one-step and two-step) for comparison of sensitivity and specificity of both methods. In the standardization of RT-ddPCR, the double-quenched probe and the temperature gradient were crucial to reduce background and improve amplitude between positive and negative droplets. The limit of detection and analytical specificity of techniques of one-step techniques showed superior performance than two-step methods described here. Additionally, the results showed 94.2% concordance (p < 0.001) for RT-ddPCR and RT-qPCR using the one-step assay approach and biological samples from Brazilian outbreaks of Senecavirus A. However, ddRT-PCR had a better performance than RT-PCR when swine serum pools were tested. According to the results, the one-step RT-ddPCR and RT-qPCR is highlighted to be used as an auxiliary diagnostic tool for Senecavirus A and for viral RNA absolute quantification in biological samples (RT-ddPCR), being a useful tool for vesicular diseases control programs., (© 2019 Blackwell Verlag GmbH.)

We examined the circulating BVDV species and genotypes among cattle herds from Northeast, Southeast, and Midwest regions in Brazil. A total of 77 animals tested positive through standard PCR. Phylogenetic analyses revealed the presence of BVDV-1a, highlighting the need for better surveillance strategies to prevent BVDV spread in the country.

Vaccinia virus (VACV) is a notorious virus for a number of scientific reasons; however, most of its notoriety comes from the fact that it was used as a vaccine against smallpox, being ultimately responsible for the eradication of that disease. Nonetheless, many different vaccinia virus strains have been obtained over the years; some are suitable to be used as vaccines, whereas others are virulent and unsuitable for this purpose. Interestingly, different vaccinia virus strains elicit different immune responses in vivo , and this is a direct result of the genomic differences among strains. In order to evaluate the net result of virus-encoded immune evasion strategies of vaccinia viruses, we compared antiviral immune responses in mice intranasally infected by the highly attenuated and nonreplicative MVA strain, the attenuated and replicative Lister strain, or the virulent WR strain. Overall, cell responses elicited upon WR infections are downmodulated compared to those elicited by MVA and Lister infections, especially in determined cell compartments such as macrophages/monocytes and CD4 + T cells. CD4 + T cells are not only diminished in WR-infected mice but also less activated, as evaluated by the expression of costimulatory molecules such as CD25, CD212, and CD28 and by the production of cytokines, including tumor necrosis factor alpha (TNF-α), gamma interferon (IFN-γ), interleukin-4 (IL-4), and IL-10. On the other hand, MVA infections are able to induce strong T-cell responses in mice, whereas Lister infections consistently induced responses that were intermediary between those induced by WR and MVA. Together, our results support a model in which the virulence of a VACV strain is proportional to its potential to downmodulate the host's immune responses. IMPORTANCE Vaccinia virus was used as vaccine against smallpox and was instrumental in the successful eradication of that disease. Although smallpox vaccination is no longer in place in the overall population, the use of vaccinia virus in the development of viral vector-based vaccines has become popular. Nonetheless, different vaccinia virus strains are known and induce different immune responses. To look into this, we compared immune responses triggered by mouse infections with the nonreplicative MVA strain, the attenuated Lister strain, or the virulent WR strain. We observed that the WR strain was capable of downmodulating mouse cell responses, whereas the highly attenuated MVA strain induced high levels of cell-mediated immunity. Infections by the intermediately attenuated Lister strain induced cell responses that were intermediary between those induced by WR and MVA. We propose that the virulence of a vaccinia virus strain is directly proportional to its ability to downmodulate specific compartments of antiviral cell responses., (Copyright © 2019 American Society for Microbiology.)

Foot-and-mouth-disease (FMD) is a highly contagious disease of domestic animals which can result in substantial economic losses, caused by the FMD virus (FMDV). The aim of this study was to develop and standardize a novel reverse transcriptase droplet digital PCR (RT-ddPCR) assay for the quantification of FMDV RNA. This assay was based upon an OIE-recognized real-time RT-PCR that detects the 3D-encoding region of FMDV. The limit of detection at 10 1.4 TCID 50 /mL and 26.5 copies was determined using FMDV-A24-Cruzeiro-virus and a plasmid containing the 3D-FMDV sequences, respectively. FMDV O, A and C serotypes and 11 species of non-FMDV were used to confirm the sensitivity and specificity of the assay. The RT-ddPCR was standardized using 60 bovine samples (representing negative and positive samples of epithelium and/or oesophageal-pharyngeal [OP] fluid) from animals suspected of vesicular diseases and previously tested by RT-qPCR. The RT-ddPCR showed robustness, sensitivity, specificity and accuracy, with similar results to the RT-qPCR. Moreover, the new RT-ddPCR diagnostic tool allowed the absolute quantification of FMDV RNA from epithelium and OP-fluid samples, as well as having the advantages of direct quantification by endpoint, eliminating the need for a calibration standard curve required in quantitative real-time RT-PCR., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: Dengue is the most prevalent arthropod-borne viral disease in the world. In this article we present results on the development, characterization and immunogenic evaluation of an alternative vaccine candidate against Dengue., Methods: The MWNT-DENV3E nanoconjugate was developed by covalent functionalization of carboxylated multi-walled carbon nanotubes (MWNT) with recombinant dengue envelope (DENV3E) proteins. The recombinant antigens were bound to the MWNT using a diimide-activated amidation process and the immunogen was characterized by TEM, AFM and Raman Spectroscopy. Furthermore, the immunogenicity of this vaccine candidate was evaluated in a murine model., Results: Immunization with MWNT-DENV3E induced comparable IgG responses in relation to the immunization with non-conjugated proteins; however, the inoculation of the nanoconjugate into mice generated higher titers of neutralizing antibodies. Cell-mediated responses were also evaluated, and higher dengue-specific splenocyte proliferation was observed in cell cultures derived from mice immunized with MWNT-DENV3E when compared to animals immunized with the non-conjugated DENV3E., Conclusions: Despite the recent licensure of the CYD-TDV dengue vaccine in some countries, results from the vaccine's phase III trial have cast doubts about its overall efficacy and global applicability. While questions about the effectiveness of the CYD-TDV vaccine still lingers, it is wise to keep at hand an array of vaccine candidates, including alternative non-classical approaches like the one presented here.

In 2011, an outbreak of severe vesicular disease occurred in the state of Pará, Amazon region. Besides proliferative or verrucous lesions, cattle showed atypical clinical signs such as diarrhea and leading to death. The animals were submitted to clinical, pathological and molecular diagnosis, and laboratory tests have confirmed the presence of Pseudocowpox virus (PCPV), a Parapoxvirus genus member, and have also found Bovine viral diarrhea virus-1 (BVDV-1), probably causing persistent infection. The results of molecular diagnostics, followed by sequencing data demonstrated the circulation of both viruses (PCPV and BVDV-1) in an area previously affected by another poxvirus, as Vaccinia virus.The cocirculation between PCPV and BVDV-1 indicates a major concern for animal health because the clinical presentation can be a severe disease. This is the first detection of PCPV in the Brazilian Amazon., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Senecavirus A (SV-A) may cause vesicular disease and neonatal mortality in pigs, and was first detected in Brazil in 2015. Samples including tissues and serum from pigs with suspected vesicular diseases were collected from January to August in 2015 from farms in the states of Minas Gerais, Santa Catarina, Goiás and Rio Grande do Sul, Brazil, and tested for the presence of SV-A by reverse transcriptase PCR. All samples were negative for foot and mouth disease virus, as well as 13 other infectious agents associated with vesicular diseases in pigs. SV-A was detected by PCR in 65/265 (24.5%) specimens. A 530 base pair fragment sequenced from the VP1 protein coding region indicated a high genetic distance from SV-A in other countries, but a common origin among the Brazilian isolates., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

The role of suppressors of cytokine signaling (SOCS) in meningoencephalitis caused by Bovine herpesvirus 5 (BoHV-5) was evaluated by intracranial infection in C57BL/6 wild-type mice (WT) and SOCS2 deficient mice (SOCS2(-/-)). Both infected groups presented weight loss, ruffled fur and hunched posture. Additionally, infected SOCS2(-/-) mice showed swollen chamfer and progressive depression. Infected WT animals developed mild meningitis, characterized by infiltration of mononuclear cells. Moreover, viral DNA was detected in liver and lung from infected WT group. This group also showed elevated brain levels of IFN-γ, IL-10, CXCL1 and CCL5, when compared with non-infected WT animals. Brain inflammation was exacerbated in infected SOCS2(-/-) mice with widespread distribution of the virus and increased brain levels of TNF-α, IFN-γ, IL-10, IL-12, CXCL1 and CCL5, when compared with WT infected mice. Moreover, infected SOCS2 deficient mice exhibited reduced brain mRNA expression of IFNα and IFNβ and increased expression of mRNA of SOCS1, compared with infected WT mice. Taken together, our study provides an insight into the role of SOCS2 in modulating the immune response to BoHV-5 infection., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Understanding of microbial communities inhabiting cattle vaginal tract may lead to a better comprehension of bovine physiology and reproductive health being of great economic interest. Up to date, studies involving cattle microbiota are focused on the gastrointestinal tract, and little is known about the vaginal microbiota. This study aimed to investigate the vaginal microbiome in Nellore cattle, heifers and cows, pregnant and non-pregnant, using a culture independent approach. The main bacterial phyla found were Firmicutes (~40-50%), Bacteroidetes (~15-25%) and Proteobacteria (~5-25%), in addition to ~10-20% of non-classified bacteria. 45-55% of the samples were represented by only ten OTUs: Aeribacillus, Bacteroides, Clostridium, Ruminococcus, Rikenella, Alistipes, Bacillus, Eubacterium, Prevotella and non-classified bacteria. Interestingly, microbiota from all 20 animals could be grouped according to the respiratory metabolism of the main OTUs found, creating three groups of vaginal microbiota in cattle. Archaeal samples were dominated by the Methanobrevibacter genus (Euryarchaeota, ~55-70%). Ascomycota was the main fungal phylum (~80-95%) and Mycosphaerella the most abundant genus (~70-85%). Hormonal influence was not clear, but a tendency for the reduction of bacterial and increase of archaeal populations in pregnant animals was observed. Eukaryotes did not vary significantly between pregnant and non-pregnant animals, but tended to be more abundant on cows than on heifers. The present work describes a great microbial variability in the vaginal community among the evaluated animals and groups (heifers and cows, pregnant and non-pregnant), which is significantly different from the findings previously reported using culture dependent methods, pointing out the need for further studies on this issue. The microbiome found also indicates that the vaginal colonization appears to be influenced by the gastrointestinal community.

We conducted a phylogenetic analysis of 22 strains of bovine leukemia virus obtained by polymerase chain reaction to amplify a 582-base pair fragment of the transcriptional regulatory region 5' long terminal repeat (LTR). Twenty-two samples of proviral DNA from peripheral blood mononuclear cells containing bovine leukemia virus from naturally infected bovine from 4 distinct geographic regions in Brazil were investigated. The products obtained by polymerase chain reaction were subjected to direct sequencing and sequence alignment. Fragments of 422 nucleotides were obtained, located between positions -118 and +303 base pairs of the 5'LTR. These fragments corresponded to 80% of the LTR region and included 56% of sub-region U3, 100% of R, and 82.5% of U5. Phylogenetic analysis of these sequences showed a high conservation degree in the 5'LTR region, with 5 well defined groups. However, a hotspot occurrence in the R-U5 region was also observed, which contained 40% of all nucleotide variability observed.

Introduction: The human T-lymphotropic virus-1 (HTLV-1) is associated with chronic inflammatory diseases such as HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), a chronic inflammatory disease. Disturbances in lipid metabolism are involved in inflammatory and demyelinating diseases., Methods: Plasma levels of triglycerides, total cholesterol, and fractions of HTLV-1-infected individuals of both sexes with different clinical progressions were determined., Results: Elevated levels of triglyceride and very low-density lipoproteins (VLDL) were exclusively detected in HTLV-1-infected women from asymptomatic and HAM/TSP groups compared with uninfected individuals (p = 0.02)., Conclusions: Elevated triglyceride and VLDL levels in HTLV-1-infected women may be related to the predominance of HAM/TSP in women.

This study presents the first description of Bovine herpesvirus 6 (BoHV-6) that was isolated from buffaloes of Amazon region in Brazil. Phylogenetic analysis showed that the BoHV-6 Brazilian strains clustered with the sequence of BoHV-6 from elsewhere available at the GenBank. It was observed in some buffaloes with lymphoproliferative disease in one herd, thus the animals were also tested for Bovine leukemia virus (BLV), which has been associated to lymphoma in bovines. All animals were negative to BLV. These results indicate that BoHV-6 is present in buffaloes in Brazil, but the importance and impact of this infection and its association with any illness is still undefined.

Background: Human T-lymphotropic virus 1 (HTLV-1) has been associated with leukemia/lymphoma (ATL) and myelopathy/tropical spastic paraparesis (HAM/TSP), in addition to other inflammatory diseases as well as infection complications. Therapeutic approaches for HTLV-1-related pathologies are limited. The labdane diterpene myriadenolide (AMY) is a natural product that exhibit biological activities, such as anti-inflammatory and antiviral activity as reported for HIV and herpesvirus., Results: We demonstrated that this natural product was able to inhibit the expression of gag-pol mRNA and substantially reduced the expression of the structural proteins p19 and gp46. Comparison of treated and untreated cells shows that AMY alters both the morphology and the release of viral particles. The Atomic Force Microscopy assay showed that the AMY treatment reduced the number of particles on the cell surface by 47%., Conclusion: We demonstrated that the labdane diterpene myriadenolide reduced the expression of the structural proteins and the budding of viral particles, besides induces altered morphogenesis of HTLV-1, conferring on AMY a new antiviral activity that may be useful for the development of new compounds with specific anti-HTLV-1 activity.

Background: HTLV-1 proviral load is a risk marker for HAM/TSP, but it is insufficient to determine the disease outcome. HTLV-1 Tax and HBZ proteins have been implicated in HAM/TSP pathogenesis in inducing cell proliferation and cytotoxic T lymphocytes response., Objectives: To quantify the expression of tax and HBZ mRNA in asymptomatic carriers (AC) and HAM patients, and to investigate their association with HAM/TSP., Study Design: We quantified the expression of HTLV-1 tax and HBZ mRNA in 37 AC and 26 HAM patients classified according to proviral load as low (AC(L) and HAM(L): <1% infected cells) or high (AC(H) and HAM(H): >1%)., Results: The AC(L) subgroup showed the lowest frequency of individuals expressing tax mRNA in comparison with AC(H), HAM(L) and HAM(H), and tax mRNA load normalized by proviral load was significantly lower in the AC(L). In turn, normalized HBZ mRNA expression was similar in all subgroups. Both tax and HBZ mRNA expression were moderately correlated with proviral load in AC (r=0.6, p<0.001) and were weaker in HAM (r=0.4, p<0.05). In contrast, the correlation between tax and HBZ mRNA load was moderate in AC (r=0.5, p=0.001) and was much stronger in HAM (r=0.8, p<0.001). In addition, HBZ mRNA load, but not tax, was significantly associated with motor disability in HAM patients (p=0.036)., Conclusions: The expression of tax mRNA seems to be best to estimate the risk of HAM/TSP, whereas HBZ mRNA appears to be a surrogate marker to disease progression, indicating that they have important but distinct roles in HAM/TSP pathogenesis., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Human T-lymphotropic virus 1 (HTLV-1) infection is associated with HTLV-associated myelopathy/tropical spastic paraparesis (HAM/TSP), which affects approximately 5% of carriers. High proviral load is a risk marker for HAM/TSP, although there is an overlap of proviral load levels in peripheral blood between asymptomatic carriers and HAM/TSP patients. In this study, receiver operating characteristic curve analysis was used to define a set point of HTLV-1 proviral load that better indicates an increased risk for HAM/TSP. Proviral load was quantified in 75 asymptomatic carriers and 78 HAM/TSP patients in a Brazilian cohort. The cut-off of proviral load was defined as 114 copies/10(4)  cells, with 78.2% sensitivity to identify true HAM/TSP patients. The mean proviral load levels were not significantly different between males and females with the same clinical status, and there was no significant correlation between proviral load and age at blood sampling, age at the onset of illness, or duration of disease. In HAM/TSP patients, proviral load was significantly higher in wheelchair-bound patients than in individuals able to walk without support and in those with the worst spinal cord injuries. Follow-up of HTLV-1-infected individuals showed that proviral load was more stable in asymptomatic carriers than in HAM/TSP patients. In a cohort study, periodically quantifying proviral load in asymptomatic carriers is necessary to identify those at risk for developing neurological disease, and it is necessary for HAM/TSP patients to monitor spinal injury and progression to walking disability. The measure of proviral load in clinical practice implicates the definition of the cut-off of proviral load and its validation during follow-up., (Copyright © 2012 Wiley Periodicals, Inc.)

This study investigated the anti-viral effects of the polyphenolic compounds Quercetin and Kaempherol on the release of HTLV-1 from the surface of MT-2 cells. Atomic force microscopy (AFM) was used to scan the surface of the MT-2 cells. MT-2 cells were fixed with 100% methanol on round glass lamina or cleaved mica and dried under UV light and laminar flow. The images were captured on a Multimode equipment monitored by a NanoScope IIId controller from Veeco Instruments Inc operated in tapping mode and equipped with phase-imaging hardware. The images demonstrated viral budding structures 131 ± 57 nm in size, indicating profuse viral budding. Interestingly, cell-free viruses and budding structures visualized on the surface of cells were less common when MT-2 was incubated with Quercetin, and no particles were seen on the surface of cells incubated with Kaempherol. In summary, these data indicate that HTLV-1 is budding constantly from the MT-2 cell surface and that polyphenolic compounds were able to reduce this viral release. Biological samples were analyzed with crude cell preparations just after cultivation in the presence of Quercetin and Kaempherol, showing that the AFM technique is a rapid and powerful tool for analysis of antiviral activity of new biological compounds., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Background: HTLV-1 infects millions of people around the world and induces myelopathy (HAM/TSP), adult T-cell leukemia (ATL) or other inflammatory or rheumatologic diseases. The host-virus interaction causes asymptomatic carriers to develop HAM/TSP. Biomarkers are needed to predict patients who are at risk for HAM/TSP. Tax is highly immunogenic and is a major target protein recognized by cytotoxic T lymphocytes. Anti-Tax antibodies are involved in HAM/TSP pathogenesis., Objectives: To assess anti-Tax IgG reactivity with a flow cytometry assay (FCA) using an infection/transfection system with Vaccinia virus and pLW44/Tax-expressing Tax and to correlate the anti-Tax response and the HTLV-1 proviral load., Study Design: : We enrolled 81 individuals: 9 HTLV-1 seronegative (NP) and 72 HTLV-1 positive (23 HTLV-1 asymptomatic carriers (AC), 12 oligosymptomatic patients (OL), 7 with rheumatologic diseases (DR) and 30 with HAM/TSP (HT)). Anti-Tax reactivity was assessed by FCA, and HTLV-1 proviral load was measured with real time PCR., Results: The HT and DR groups showed greater anti-Tax IgG reactivity (p<0.001 and p<0.05 comparing HT to the OL and AC group, respectively; p<0.05 comparing DR to the OL group), and the reactivity in the DR+HT group was significantly different when compared to the AC group (p<0.05) and to the OL group (p<0.001). The proviral load was higher in the HT group compared to the OL (p<0.001) and in the HT+DR group compared to OL (p<0.001). There was no correlation between anti-Tax IgG reactivity and proviral load in any of the HTLV-1-infected groups., Conclusion: These findings suggest that although anti-Tax IgG reactivity and the HTLV-1 proviral load are important markers of the development of HTLV-1-associated diseases, their levels are not correlated., (Copyright © 2010 Elsevier B.V. All rights reserved.)

The high proportion of indeterminate results of the screening test for human T-lymphotropic virus (HTLV) infection has been a challenge worldwide. In this study, 60 persons with seroindeterminate results for HTLV were followed until their serological status was defined. At least two independent serological tests (EIA and WB) from sequential samples were performed at an average interval of 4.4 years, totaling 141 serum samples tested. Seroconversion occurred in 12 individuals (reactive by EIA, positive by WB and PCR), and 48 were classified as false reactions (non-reactive EIA and negative PCR, but indeterminate WB). The seroconverter group had epidemiological features similar to those seen in HTLV-1 carriers, and the average time of follow-up for seroconversion was 4 years. In the group with false reactions, the most frequent indeterminate WB pattern in the samples was the presence of p24 alone. This pattern was absent in the seroconverter group, suggesting that p24 alone is an indicator of false reactivity. In contrast, the presence of p19 and p24 seems to be an indicator of true reactivity, since this pattern was frequent (66.7%) among the seroconverters and much less common (10.4% of the first samples) among the individuals with false reactions (P = 0.0001). Thus, HTLV infection may be suspected when reactivity to p19 and p24 is observed. Individuals with an indeterminate WB pattern should be followed-up and retested. The improvement of the HTLV algorithm screening of blood donors has been necessary to reduce inconclusive results and to avoid unnecessary follow-up to define the status of infection., ((c) 2010 Wiley-Liss, Inc.)