Differential gene expression of cytokines, receptors, and miRNAs in individuals living with HIV-1 and vaccinated against yellow fever.

Between 2016 and 2018, Brazil faced a yellow fever (YF) outbreak, which led to an expansion of vaccination coverage. The coexistence of the YF outbreak and the HIV-1 epidemic in Brazil raised concerns regarding the immune response and vaccine effectiveness in individuals living with HIV (PLWH). The aim of this study was to investigate the immune response to YF vaccination in PLWH and HIV-uninfected individuals as controls. Transcript levels of immunomodulatory molecules, including IL-6, IL-10, IL-21, TGF-ß, CD19, CD163, miR-21, miR-146, and miR-155, were measured using RTqPCR. TCD4+ cells were evaluated by cytometry, and neutralizing antibody (Nab) titers were detected by a micro plaque-reduction neutralization test. The findings of our study revealed several noteworthy observations. First, there was a notable reduction in the circulation of TCD4+ cells postvaccination. Among people living with HIV (PLWH), we observed an increase in the expression of IL-10 following vaccination, while IL-6 expression was diminished in PLWH with lower TCD4+ counts. Furthermore, we identified the downregulation of CD19 and TGF-ß, along with the upregulation of IL-21 and CD163. Notably, we observed positive correlations between the levels of IL-10/IL-21, IL-10/CD163, and IL-6/CD19. Additionally, there was a positive correlation between miRNAs 146 and 155. It is important to emphasize that all participants exhibited robust neutralizing antibody responses after receiving 17DD YF vaccination. In this context, the gene expression data presented can be useful for biomarker studies of protective antibodies induced by YF vaccination. This study sheds light on immune mechanisms in individuals living with HIV and YF vaccination.

The impact of early anti-SARS-CoV-2 antibody production on the length of hospitalization stay among COVID-19 patients.

IMPORTANCE: The study provides valuable insights into the sociodemographic characteristics, clinical outcomes, and humoral immune response of those affected by the virus that has devastated every field of human life since 2019; the COVID-19 patients. Firstly, the association among clinical manifestations, comorbidities, and the production of neutralizing antibodies (Nabs) against SARS-CoV-2 is explored. Secondly, varying levels of Nabs among patients are revealed, and a significant correlation between the presence of Nabs and a shorter duration of hospitalization is identified, which highlights the potential role of Nabs in predicting clinical outcomes. Lastly, a follow-up conducted 7 months later demonstrates the progression and persistence of Nabs production in recovered unvaccinated individuals. The study contributes essential knowledge regarding the characteristics of the study population, the early humoral immune response, and the dynamics of Nabs production over time. These findings have significant implications for understanding the immune response to COVID-19 and informing clinical management approaches.

Immunogenicity and reactogenicity of yellow fever vaccine in people with HIV.

OBJECTIVE: To evaluate immunogenicity and reactogenicity of yellow fever (YF) vaccine in people with HIV (PWH) compared to HIV-uninfected controls. DESIGN: In this longitudinal interventional trial (NCT03132311), PWH with CD4 + cell count ≥200 cells/µl and controls, aged 18-59, without a previous history of YF vaccination received a single standard dose of YF vaccine (17DD) and were followed at Days 5, 30 and Year 1. METHODS: YF-neutralization titers were measured at Days 0, 30 and Year 1 and geometric mean titers (GMT) were calculated. Adverse events (AE) and YF virus detection were measured at Days 5 and 30. Linear regression evaluated factors associated with YF-neutralization titers. RESULTS: Two hundred and eighteen PWH and 82 controls were included. At baseline, all PWH were using antiretroviral therapy; 92.6% had undetectable HIV viral load (VL) and median CD4 + cell count was 630 cells/µl [interquartile range (IQR) 463-888]. YF vaccine was safe and there were no serious AEs. At Day 30, seroconversion was observed in 98.6% of PWH [95% confidence interval (CI): 95.6-99.6] and in 100% of controls (95% CI: 93.9-100); at Year 1, 94.0% of PWH (95% CI: 89.6-96.7) and 98.4% of controls (95% CI 90.3-99.9) were seropositive. PWH had lower GMTs than controls at Day 30 and Year 1. Baseline VL >1000 copies/ml, low CD4 + cell count and low CD4 + /CD8 + ratio were associated with lower YF-neutralization titers. CONCLUSIONS: YF vaccine is safe in PWH with CD4 + cell count ≥200 cells/µl. YF vaccine immunogenicity is impaired in PWH, particularly among those with high VL, low CD4 + cell count and low CD4 + /CD8 + ratio at vaccination and YF-neutralization titers decays over time.

Ongoing HIV-1 evolution and reservoir reseeding in two elite controllers with genetically diverse peripheral proviral quasispecies.

BACKGROUND: Elite controllers (EC) are human immunodeficiency virus (HIV)-positive individuals who can maintain low viral loads for extended periods without antiretroviral therapy due to multifactorial and individual characteristics. Most have a small HIV-1 reservoir composed of identical proviral sequences maintained by clonal expansion of infected CD4+ T cells. However, some have a more diverse peripheral blood mononuclear cell (PBMC)-associated HIV-1 reservoir with unique sequences. OBJECTIVES: To understand the turnover dynamics of the PBMC-associated viral quasispecies in ECs with relatively diverse circulating proviral reservoirs. METHODS: We performed single genome amplification of the env gene at three time points during six years in two EC with high intra-host HIV DNA diversity. FINDINGS: Both EC displayed quite diverse PBMCs-associated viral quasispecies (mean env diversity = 1.9-4.1%) across all time-points comprising both identical proviruses that are probably clonally expanded and unique proviruses with evidence of ongoing evolution. HIV-1 env glycosylation pattern suggests that ancestral and evolving proviruses may display different phenotypes of resistance to broadly neutralising antibodies consistent with persistent immune pressure. Evolving viruses may progressively replace the ancestral ones or may remain as minor variants in the circulating proviral population. MAIN CONCLUSIONS: These findings support that the high intra-host HIV-1 diversity of some EC resulted from long-term persistence of archival proviruses combined with the continuous reservoir's reseeding and low, but measurable, viral evolution despite undetectable viremia.

Inflammasome genes polymorphisms are associated with progression to mechanical ventilation and death in a cohort of hospitalized COVID-19 patients in a reference hospital in Rio de Janeiro, Brazil.

COVID-19 has a broad spectrum of clinical manifestations. We assessed the impact of single nucleotide polymorphisms (SNPs) of inflammasome genesas risk factors for progression toCOVID-19 critical outcomes, such as mechanical ventilation support (MVS) or death.The study included 451 hospitalized individuals followed up at the INI/FIOCRUZ, Rio de Janeiro, Brazil, from 06/2020 to 03/2021. SNPs genotyping was determined by Real-Time PCR. We analyzed risk factors for progression to MVS (n = 174[38.6 %]) or death (n = 175[38.8 %])as a result of COVID-19 by Cox proportional hazardmodels.Slower progression toMVSwas associated with allele G (aHR = 0.66;P = 0.005) or the genotype G/G (aHR = 0.391;P = 0.006) in the NLRP3 rs10754558 or the allele G (aHR = 0.309;P = 0.004) in the IL1ßrs1143634, while C allele in the NLRP3 rs4612666 (aHR = 2.342;P = 0.006) or in the rs10754558 (aHR = 2.957;P = 0.005) were associated with faster progression to death. Slower progression to death was associated to allele G (aHR = 0.563;P = 0.006) or the genotype A/G (aHR = 0.537;P = 0.005) in the CARD8 rs6509365; the genotype A/C in the IFI16 rs1101996 (aHR = 0.569;P = 0.011); the genotype T/T (aHR = 0.394;P = 0.004) or allele T (aHR = 0.68;P = 0.006) in the NLRP3 rs4612666, and the genotype G/G (aHR = 0.326;P = 0.005) or allele G (aHR = 0,68;P = 0.014) in the NLRP3 rs10754558. Our results suggest that inflammasome genetic variations might influence the critical clinical course of COVID-19.

Ongoing HIV-1 evolution and reservoir reseeding in two elite controllers with genetically diverse peripheral proviral quasispecies

BACKGROUND Elite controllers (EC) are human immunodeficiency virus (HIV)-positive individuals who can maintain low viral loads for extended periods without antiretroviral therapy due to multifactorial and individual characteristics. Most have a small HIV-1 reservoir composed of identical proviral sequences maintained by clonal expansion of infected CD4+ T cells. However, some have a more diverse peripheral blood mononuclear cell (PBMC)-associated HIV-1 reservoir with unique sequences. OBJECTIVES To understand the turnover dynamics of the PBMC-associated viral quasispecies in ECs with relatively diverse circulating proviral reservoirs. METHODS We performed single genome amplification of the env gene at three time points during six years in two EC with high intra-host HIV DNA diversity. FINDINGS Both EC displayed quite diverse PBMCs-associated viral quasispecies (mean env diversity = 1.9-4.1%) across all time-points comprising both identical proviruses that are probably clonally expanded and unique proviruses with evidence of ongoing evolution. HIV-1 env glycosylation pattern suggests that ancestral and evolving proviruses may display different phenotypes of resistance to broadly neutralising antibodies consistent with persistent immune pressure. Evolving viruses may progressively replace the ancestral ones or may remain as minor variants in the circulating proviral population. MAIN CONCLUSIONS These findings support that the high intra-host HIV-1 diversity of some EC resulted from long-term persistence of archival proviruses combined with the continuous reservoir's reseeding and low, but measurable, viral evolution despite undetectable viremia.

Inflammasome Genetic Variants Are Associated with Protection to Clinical Severity of COVID-19 among Patients from Rio de Janeiro, Brazil.

COVID-19 has a broad spectrum of clinical manifestations, from asymptomatic or mild/moderate symptoms to severe symptoms and death. The mechanisms underlying its clinical evolution are still unclear. Upon SARS-CoV-2 infection, host factors, such as the inflammasome system, are activated by the presence of the virus inside host cells. The search for COVID-19 risk factors is of relevance for clinical management. In this study, we investigated the impact of inflammasome single-nucleotide polymorphisms (SNPs) in SARS-CoV-2-infected individuals with distinct severity profiles at clinical presentation. Patients were divided into two groups according to disease severity at clinical presentation based on the WHO Clinical Progression Scale. Group 1 included patients with mild/moderate disease (WHO < 6; n = 76), and group 2 included patients with severe/critical COVID-19 (WHO ≥ 6; n = 357). Inpatients with moderate to severe/critical profiles were recruited and followed-up at Hospital Center for COVID-19 Pandemic - National Institute of Infectology (INI)/FIOCRUZ, RJ, Brazil, from June 2020 to March 2021. Patients with mild disease were recruited at Oswaldo Cruz Institute (IOC)/FIOCRUZ, RJ, Brazil, in August 2020. Genotyping of 11 inflammasome SNPs was determined by real-time PCR. Protection and risk estimation were performed using unconditional logistic regression models. Significant differences in NLRP3 rs1539019 and CARD8 rs2043211 were observed between the two groups. Protection against disease severity was associated with the A/A genotype (ORadj = 0.36; P = 0.032), allele A (ORadj = 0.93; P = 0.010), or carrier-A (ORadj = 0.45; P = 0.027) in the NLRP3 rs1539019 polymorphism; A/T genotype (ORadj = 0.5; P = 0.045), allele T (ORadj = 0.93; P = 0.018), or carrier-T (ORadj = 0.48; P = 0.029) in the CARD8 rs2043211 polymorphism; and the A-C-G-C-C (ORadj = 0.11; P = 0.018), A-C-G-C-G (ORadj = 0.23; P = 0.003), C-C-G-C-C (ORadj = 0.37; P = 0.021), and C-T-G-A-C (ORadj = 0.04; P = 0.0473) in NLRP3 genetic haplotype variants. No significant associations were observed for the other polymorphisms. To the best of our knowledge, this is the first study demonstrating an association between CARD8 and NLRP3 inflammasome genetic variants and protection against COVID-19 severity, contributing to the discussion of the impact of inflammasomes on COVID-19 outcomes.

Increased biomarkers of cardiovascular risk in HIV-1 viremic controllers and low persistent inflammation in elite controllers and art-suppressed individuals.

HIV controllers (HICs) are models of HIV functional cure, although some studies have shown persistent inflammation and increased rates of atherosclerosis in HICs. Since immune activation/inflammation contributes to the pathogenesis of cardiovascular diseases (CVD), we evaluated clinical data and inflammation markers in HIV-1 viremic controllers (VC), elite controllers (EC), and control groups (HIV positive individuals with virological suppression by antiretroviral therapy-cART; HIV negative individuals-HIVneg) to assess whether they presented elevated levels of inflammation markers also associated with CVD. We observed the highest frequencies of activated CD8+ T cells in VCs, while EC and cART groups presented similar but slightly altered frequencies of this marker when compared to the HIVneg group. Regarding platelet activation, both HICs groups presented higher expression of P-selectin in platelets when compared to control groups. Monocyte subset analyses revealed lower frequencies of classical monocytes and increased frequencies of non-classical and intermediate monocytes among cART individuals and in EC when compared to HIV negative individuals, but none of the differences were significant. For VC, however, significant decreases in frequencies of classical monocytes and increases in the frequency of intermediate monocytes were observed in comparison to HIV negative individuals. The frequency of monocytes expressing tissue factor was similar among the groups on all subsets. In terms of plasma markers, VC had higher levels of many inflammatory markers, while EC had higher levels of VCAM-1 and ICAM-1 compared to control groups. Our data showed that VCs display increased levels of inflammation markers that have been associated with CVD risk. Meanwhile, ECs show signals of lower but persistent inflammation, comparable to the cART group, indicating the potential benefits of alternative therapies to decrease inflammation in this group.

A case report of HIV-1 superinfection in an HIV controller leading to loss of viremia control: a retrospective of 10 years of follow-up.

BACKGROUND: HIV controllers (HICs) are a rare group of HIV-1-infected individuals able to naturally control viral replication. Several studies have identified the occurrence of HIV dual infections in seropositive individuals leading to disease progression. In HICs, however, dual infections with divergent outcomes in pathogenesis have been described. CASE PRESENTATION: Here, we present a case report of a HIC diagnosed in late 1999 who displayed stable CD4+ T cell levels and low plasmatic viral load across 12 years of follow-up. In early 2013, the patient started to present an increase in viral load, reaching a peak of 10,000 copies/ml in early 2014, followed by an oscillation of viremia at moderate levels in the following years. The genetic diversity of env proviral quasispecies from peripheral blood mononuclear cells (PBMCs) was studied by single genome amplification (SGA) at six timepoints across 2009-2017. Phylogenetic analyses of env sequences from 2009 and 2010 samples showed the presence of a single subtype B variant (called B1). Analyses of sequences from 2011 and after revealed an additional subtype B variant (called B2) and a subsequent dominance shift in the proviral quasispecies frequencies, with the B2 variant becoming the most frequent from 2014 onwards. Latent syphilis related to unprotected sexual intercourse was diagnosed a year before the first detection of B2, evidencing risk behavior and supporting the superinfection hypothesis. Immunologic analyses revealed an increase in CD8+ and CD4+ T cell immune activation following viremia increase and minor T cell subset alterations during follow-up. HIV-specific T cell responses remained low throughout the follow-up period. CONCLUSIONS: Altogether, these results show that loss of viremia control in the HIC was associated with superinfection. These data alert to the negative consequences of reinfection on HIV pathogenesis, even in patients with a long history of viremia control and an absence of disease progression, reinforcing the need for continued use of adequate prevention strategies.

Reduction of HIV-1 Reservoir Size and Diversity After 1 Year of cART Among Brazilian Individuals Starting Treatment During Early Stages of Acute Infection.

The aim of early combined antiretroviral therapy (cART) of HIV is to limit the seeding of the viral reservoir during the initial phase of infection and, consequently, decrease intrahost viral diversity. Here, we assessed the effect of early cART on size and complexity of the proviral reservoir. Peripheral blood mononuclear cell (PBMC) and plasma samples were obtained from ten HIV-infected Brazilian individuals diagnosed at the acute phase of infection, before (PREART) and 12 months (M12ART) after suppressive cART. HIV proviral reservoir size was determined by quantitative real-time PCR; intrahost viral diversity of the env C2-V3 region was assessed by single genome amplification or next-generation sequencing in PBMC and plasma, respectively. Mean nucleotide diversity (π) and normalized Shannon entropy (HSN) were used to infer the complexity of the viral population. Compared to PREART, M12ART saw an immunological recovery with a gain of ∼200 CD4+ T cells (P = 0.008) and a normalization of the CD4/CD8 ratio [1.0 (IQR: 0.88-1.18), P = 0.016], as well as a significant decrease in HIV-1 RNA (∼4 log, P = 0.004) and DNA (∼1 log, P = 0.002) levels. The median time to achieve viral suppression was 3 months (IQR: 2.8-5.8 months). The high intermixing between sequences from both visits suggests that the HIV-1 DNA reservoir remained remarkably stable under cART. After 1 year of cART, there was a minor reduction in proviral π (PreART = 0.20 vs. M12ART = 0.10; P = 0.156) but a significant decrease in HSN (PreART = 0.41 vs. M12ART = 0.25; P = 0.019). We found no correlation between π or HSN at PreART and the rate of HIV DNA decay, T CD4+ counts, or CD4/CD8 ratio at M12ART. Based on a small cohort of Brazilian infected individuals under early cART and analyses of the env region, 1 year of follow-up suggested a reservoir size reduction, allowed a significant decrease of HIV-1 complexity, and achieved immunological restoration regardless of the initial HIV-1 plasma viral load, CD4+ T cell counts, or HIV-1 subtype. However, further studies in the Brazilian setting aiming a longer follow-up and larger cohort are required in this field.

Reduction of inflammation and T cell activation after 6 months of cART initiation during acute, but not in early chronic HIV-1 infection.

OBJECTIVES: To investigate the impact of early combined antiretroviral therapy (cART) on inflammation biomarkers and immune activation during acute and early chronic HIV-1 infection. METHODS: We included 12 acute (AHI), 11 early chronic (EcHI), and 18 late chronic HIV-1-infected (LcHI) individuals who were treated with cART and 18 HIV-1-uninfected (HIV-neg) individuals. Plasmatic levels of inflammation biomarkers, CD8+CD38+HLA-DR+ T cell frequencies, CD4 T cell counts, CD4/CD8 ratio, total HIV-1 DNA and plasmatic viral load were evaluated. Mann-Whitney test, Pearson and Spearman correlation, and linear regression models were used for statistical analyses. RESULTS: IP-10, IL-18, and sCD163 were significantly elevated at pre-ART in the AHI and EcHI groups, showing a significant reduction after 6 months of cART in the AHI group, achieving similar levels to the HIV-neg group. For the EcHI group, the IP-10 and sCD163 levels were also significantly reduced on M6-ART; however, IP-10 levels remained higher than in the HIV-neg group, and no significant reduction of IL-18 levels was observed. The CD8+ T cell activation levels were elevated in the AHI and EcHI groups at pre-ART and showed a significant reduction on M6-ART, but they were similar to levels seen for HIV-neg only after 12 months of cART. At pre-ART, IP-10 levels but not IL-18 levels were positively correlated with HIV-1 viral load in the AHI group. CONCLUSIONS: Early initiation of cART in HIV infection can reduce systemic inflammation, but the earlier normalization of the inflammation markers was only observed when cART was initiated in the acute phase of infection. A slower dynamic of reduction was observed for CD8+ T cell activation.

Next-generation sequencing analyses of the emergence and maintenance of mutations in CTL epitopes in HIV controllers with differential viremia control.

BACKGROUND: Despite the low level of viral replication in HIV controllers (HICs), studies have reported viral mutations related to escape from cytotoxic T-lymphocyte (CTL) response in HIV-1 plasma sequences. Thus, evaluating the dynamics of the emergence of CTL-escape mutants in HICs reservoirs is important for understanding viremia control. To analyze the HIV-1 mutational profile and dynamics of CTL-escape mutants in HICs, we selected 11 long-term non-progressor individuals and divided them into the following groups: (1) viremic controllers (VCs; n = 5) and (2) elite controllers (ECs; n = 6). For each individual, we used HIV-1 proviral DNA from PBMCs related to earliest (VE) and latest (VL) visits to obtain gag and nef sequences using the Illumina HiSeq system. The consensus of each mapped gene was used to assess viral divergence, and next-generation sequencing data were employed to identify SNPs and variations within and flanking CTL epitopes. RESULTS: Divergence analysis showed higher values for nef compared to gag among the HICs. EC and VC groups showed similar divergence rates for both genes. Analysis of the number of SNPs showed that VCs present more variability in both genes. Synonymous/non-synonymous mutation ratios were < 1 for gag among ECs and for nef among ECs and VCs, exhibiting a predominance of non-synonymous mutations. Such mutations were observed in regions encoding CTL-restricted epitopes in all individuals. All ECs presented non-synonymous mutations in CTL epitopes but generally at low frequency (< 1%); all VCs showed a high number of mutations, with significant frequency changes between VE and VL visits. A higher frequency of internal mutations was observed for gag epitopes, with significant changes across visits compared to Nef epitopes, indicating a pattern associated with differential genetic pressure. CONCLUSIONS: The high genetic conservation of HIV-1 gag and nef among ECs indicates that the higher level of viremia control restricts the evolution of both genes. Although viral replication levels in HICs are low or undetectable, all individuals exhibited CTL epitope mutations in proviral gag and nef variants, indicating that potential CTL escape mutants are present in HIC reservoirs and that situations leading to a disequilibrium of the host-virus relationship can result in the spread of CTL-escape variants.

Avaliação da resposta de células T frente aos peptídeos de GAG e NEF do HIV-1 e de parâmetros imunológicos e genéticos associados ao controle da replicação viral / Evaluation of t cells responses against hiv-1 gag and nef peptides and immunological and genetic parameters associated to control of viral replication

A pandemia do HIV-1 é a infecção emergente mais importante das últimas décadas. O desenvolvimento de uma vacina é colocado como a melhor estratégia para o controle da pandemia. No entanto, entre os candidatos vacinais que evoluíram para testes clínicos de eficácia, apenas um mostrou resultados positivos, mas com uma modesta eficácia (31,2 por cento). Além da busca por uma vacina eficiente contra a infecção pelo HIV-1, o desenvolvimento de estratégias para se atingir a cura também é essencial. Considerando esses dois objetivos principais, diversos fatores são colocados como obstáculos, sendo a enorme diversidade genética do HIV-1 e a falta de correlatos de proteção contra a doença ou a infecção, os pontos centrais e nos quais focamos nossa atenção. No primeiro trabalho, foi avaliada a resposta de células T frente a peptídeos derivados de sequências consensos e sequências de isolados virais mais próximos ao consenso (CVI) dos três subtipos prevalentes no Brasil,B, C e F1 e do grupo M. O estudo incluiu 32 indivíduos infectados com o HIV-1, subtipo B (n= 13), subtipo C (n = 11) e subtipo F1 (n = 8). As respostas específicas frente a Gag e Nef foram avalidas usando o ensaio de ELISpot IFN-gama. Peptídeos baseados nas sequências CVI apresentaram capacidade de redução da distância genética e de detecção da resposta de células T similar ao observado para as sequências consenso. Em geral, o nível de reatividade cruzada entre os subtipos B e F1 foi maior do que entre os subtipos B e C ou entre os subtipos C e F1. Esses resultados sugerem que o obstáculo imposto pela diversidade genética no desenho de vacinas é dependente dos subtipos envolvidos. No segundo trabalho foi avaliada a resposta de células T de indivíduos controladores da replicação viral frente aos peptídeos consenso, derivados do primeiro estudo...

Short communication: neutralizing antibodies in HIV-1-infected Brazilian individuals.

Tests for the detection of the humoral immune response to HIV-1 have to be standardized and established, demanding regional efforts. For this purpose the neutralizing antibody (NAb) assay for HIV-1 in TZM-bl cells was introduced in Brazil. Twenty plasma samples from HIV-1-infected individuals were assayed: 10 progressors and 10 long-term nonprogressors. These were tested against eight env-pseudotyped viruses (psVs) in the TZM-bl NAb assay and against HIV-1 strain HTLV/IIIB (HIV-1 IIIB) in primary lymphocytes. Forty-four percent of the samples showed neutralizing titers for psVs and 55% for HIV-1 IIIB. Plasma from progressors showed a broader neutralization and a higher potency. The introduction of these reference reagents encourages the participation of Brazil in future comparative assessments of anti-HIV-1 antibodies.

Higher cross-subtype IFN-γ ELISpot responses to Gag and Nef peptides in Brazilian HIV-1 subtype B- and F1- than in C-infected subjects.

HIV-1 diversity has been considered a huge challenge for the HIV-1 vaccine development. To overcome it, immunogens based on centralized sequences, as consensus, have been tested. In Brazil, the co-circulation of three subtypes offers a suitable scenario to test T cell cross-subtype responses to consensus sequences. Furthermore, we included peptides based on closest viral isolates (CVI) from each subtype analyzed to compare with T cell responses detected against the consensus sequences. The study included 32 subjects infected with HIV-1 subtype B (n=13),C (n=11), and F1 (n=8). Gag and Nef-specific T cell responses were evaluated by IFN-γ-ELISpot assay. Peptides based on CVI sequences were similar to consensus in both reducing genetic distance and detecting T cell responses. A high cross-subtype response between B and F1 in both regions was observed in HIV-1 subtype B and F1-infected subjects. We also found no significant difference in responses to subtype B and C consensus peptides among subtype B-infected subjects. In contrast, the magnitude of T cell responses to consensus C peptides in the Gag region was higher than to consensus B peptides among HIV-1 subtype C-infected subjects. Regarding Nef, subtype C-infected subjects showed higher values to consensus C than to consensus F1 peptides. Moreover, subtype F1-infected subjects presented lower responses to subtype C peptides than to subtype F1 and B. A similar level of responses was detected with group M based peptides in subtype B and F1 infected subjects. However, among subtype C infected subjects, this set of peptides detected lower levels of response than consensus C. Overall, the level of cross-subtype response between subtypes B and F1 was higher than between subtype C and B or C and F1. Our data suggests that the barrier of genetic diversity in HIV-1 group M for vaccine design may be dependent on the subtypes involved.

Avaliação da antigenicidade de peptídeos sintéticos correspondentes a região nef do HIV-1, obtidos a partir de sequências consensos e de isolados dos subtipos B e F1 / Evaluation of the antigenicity of synthetic peptides corresponding to the nef region of HIV-1 obtained from consensus sequences and isolates of subtypes B and F1

Sequências virais centrais, incluindo consenso, ancestral e centro-da-árvore, vêm sendo propostas para o desenho de potenciais imunógenos para o desenho de uma vacina anti-HIV/Aids, por minimizarem a distância genética em relação aos vírus circulantes. No Brasil a epidemia de Aids é causada primariamente pelo subtipo B, seguido dos subtipos F1 e C, em adição a recombinantes B/F1 e B/C. Este estudo teve como objetivo avaliar o uso potencial de sequências consenso comparadas a sequências de isolados virais mais próximos, na definição de antígenos vacinais. Bem como determinar o impacto do polimorfismo viral na resposta imune de indivíduos infectados pelo HIV-1. Esta avaliação da resposta imune foi realizada com células mononucleares do sangue periférico (CMSP) de indivíduos infectados pelo subtipo B e F1, incluindo um grupo de controladores da carga viral e indivíduos não progressores de longo termo, usando o ensaio de ELISpot IFN-gama. Duas regiões em Nef (R1 e R3) apresentaram alta frequência de resposta, 84por cento e 73por cento para o pool de peptídeos referente ao consenso B e 65por cento e 69por cento para o consenso F1, respectivamente. Em indivíduos infectados pelo subtipo B a frequência de resposta tanto para o pool de peptídeos baseados na sequência do isolado quanto na sequência consenso foi igual na R1 (93por cento) e muito próxima na região 2, 28por cento para o consenso contra 21por cento do isolado. Na R3, as sequências do consenso e do isolado no subtipo B são idênticas, e 71por cento dos indivíduos responderam ao pool dessa região. Nos indivíduos infectados pelo subtipo F1 foram encontrados valores similares na frequência de resposta para a R1, 44por cento e 55por cento, e idênticos na R3, 66por cento, para o consenso e o isolado, respectivamente. A magnitude de resposta não foi significativamente diferente entre o consenso e isolado (P maior que 0,05) para ambas as regiões tanto para os indivíduos infectados pelo subtipo B quanto pelo F1. Foi demonstrada uma forte reatividade cruzada frente aos peptídeos derivados dos consensos dos subtipos B e F1 e do grupo M. Nos indivíduos infectados pelo subtipo B, 79por cento das respostas foram detectadas tanto com peptídeos do consenso B, como F1 e M, nos indivíduos infectados pelo subtipo F1 essas respostas representaram 68por cento. Juntos esses dados indicam que tanto a estratégia do consenso, quanto a do isolado mais próximo é capaz de estimular uma resposta HIV específica. Além disso, nosso estudo aponta que sequências referentes tanto ao subtipo B quanto ao F1 poderiam servir como base para o desenho de imunógenos pautados na proteína Nef.