AEGiS-11IAC: Selection of viral epitopes by cytolytic T cells from HLA-A11 HIV-infected individuals.

11th International AIDS Conference


Vancouver, British Columbia — July 7-12, 1996

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Selection of viral epitopes by cytolytic T cells from HLA-A11 HIV-infected individuals.

Int Conf AIDS 1996 Jul 7-12; 11:223 (abstract no. Tu.A.285)
Culmann-Penciolelli B, Guillet JG, Gomard E; INSERM U445, ICGM, Paris, France.

OBJECTIVES: To determine how HIV-infected individuals select their CTL epitopes according to their HLA phenotype.

METHODS: Three HIV-positive HLA-All individuals were tested for their lytic activity against four HIV epitopes restricted by HLA-All. Two epitopes are derived from the NEF protein (aa73-82, 84-92) and the two others are derived from the reverse transcriptase protein (aa325-333, 508-525). PBMC were stimulated with autologous irradiated PHA blasts and cultured for 14 days. Chromium release assay was performed to evaluate CTL activity.

RESULTS: We first showed that these three subjects are different concerning the recognition of these different HLA-All restricted epitopes. We demonstrate that one of them recognized only the pol 325-333 peptide whereas the second one recognized both pol peptides and the third recognized both nef peptides. These results indicate either a phenomenon of immunodominance or the existence of escaping mutants which avoid CTL recognition. Experiments of dilution of the peptides during the cytolytic assay revealed differences between these 4 epitopes. The capacity of a given peptide to sensitize targets for lysis at very low concentration does not seem to be correlated with the capacity of this peptide to be recognized by all individuals. Analysis of autologous HIV sequences derived from these 3 subjects will allow us to investigate a possible escaping to the cytolytic response.

CONCLUSIONS: This study allows us to demonstrate that despite the presence of the HLA-All restricting molecule, not all HLA-All HIV-positive individuals are able to elicit a specific response against HLA-All restricted epitopes.

Keywords: AEGIS, HLA-A Antigens, HIV, Epitopes, T-Lymphocytes, Gene Products, nef, HIV Infections, HIV Antigens, Peptides, HIV Envelope Protein gp120, HIV Seropositivity, HLA-A11, virology, ICA11KWDaegis,hla-aantigens,hiv,epitopes,t-lymphocytes,geneproducts,nef,hivinfections,hivantigens,peptides,hivenvelopeproteingp120,hivseropositivity,hla-a11,virology,ica11

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TuA285

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