RESUMO
The Center for HIV/AIDS Vaccine Immunology (CHAVI) consortium was established to determine the host and virus factors associated with HIV transmission, infection and containment of virus replication, with the goal of advancing the development of an HIV protective vaccine. Studies to meet this goal required the use of cryopreserved Peripheral Blood Mononuclear Cell (PBMC) specimens, and therefore it was imperative that a quality assurance (QA) oversight program be developed to monitor PBMC samples obtained from study participants at multiple international sites. Nine site-affiliated laboratories in Africa and the USA collected and processed PBMCs, and cryopreserved PBMC were shipped to CHAVI repositories in Africa and the USA for long-term storage. A three-stage program was designed, based on Good Clinical Laboratory Practices (GCLP), to monitor PBMC integrity at each step of this process. The first stage evaluated the integrity of fresh PBMCs for initial viability, overall yield, and processing time at the site-affiliated laboratories (Stage 1); for the second stage, the repositories determined post-thaw viability and cell recovery of cryopreserved PBMC, received from the site-affiliated laboratories (Stage 2); the third stage assessed the long-term specimen storage at each repository (Stage 3). Overall, the CHAVI PBMC QA oversight program results highlight the relative importance of each of these stages to the ultimate goal of preserving specimen integrity from peripheral blood collection to long-term repository storage.
Assuntos
Vacinas contra a AIDS/uso terapêutico , Ensaios Clínicos como Assunto/normas , Criopreservação/normas , Infecções por HIV/terapia , Testes Imunológicos/normas , Laboratórios/normas , Ensaio de Proficiência Laboratorial/normas , Leucócitos Mononucleares/imunologia , Monitorização Imunológica/normas , Manejo de Espécimes/normas , África , Sobrevivência Celular , Consenso , Comportamento Cooperativo , Fidelidade a Diretrizes/normas , Infecções por HIV/diagnóstico , Infecções por HIV/imunologia , Infecções por HIV/virologia , Humanos , Cooperação Internacional , Leucócitos Mononucleares/virologia , Estudos Longitudinais , Variações Dependentes do Observador , Guias de Prática Clínica como Assunto/normas , Valor Preditivo dos Testes , Desenvolvimento de Programas , Avaliação de Programas e Projetos de Saúde , Controle de Qualidade , Reprodutibilidade dos Testes , Fatores de Tempo , Resultado do Tratamento , Estados Unidos , Fluxo de TrabalhoRESUMO
An understanding of the relationship between the breadth and magnitude of T-cell epitope responses and viral loads is important for the design of effective vaccines. For this study, we screened a cohort of 46 subtype C human immunodeficiency virus type 1 (HIV-1)-infected individuals for T-cell responses against a panel of peptides corresponding to the complete subtype C genome. We used a gamma interferon ELISPOT assay to explore the hypothesis that patterns of T-cell responses across the expressed HIV-1 genome correlate with viral control. The estimated median time from seroconversion to response for the cohort was 13 months, and the order of cumulative T-cell responses against HIV proteins was as follows: Nef > Gag > Pol > Env > Vif > Rev > Vpr > Tat > Vpu. Nef was the most intensely targeted protein, with 97.5% of the epitopes being clustered within 119 amino acids, constituting almost one-third of the responses across the expressed genome. The second most targeted region was p24, comprising 17% of the responses. There was no correlation between viral load and the breadth of responses, but there was a weak positive correlation (r = 0.297; P = 0.034) between viral load and the total magnitude of responses, implying that the magnitude of T-cell recognition did not contribute to viral control. When hierarchical patterns of recognition were correlated with the viral load, preferential targeting of Gag was significantly (r = 0.445; P = 0.0025) associated with viral control. These data suggest that preferential targeting of Gag epitopes, rather than the breadth or magnitude of the response across the genome, may be an important marker of immune efficacy. These data have significance for the design of vaccines and for interpretation of vaccine-induced responses.