Novel HLA-II-restricted HIV-1 specific epitopes stimulate CD4⁺ T cell responses during chronic HIV infection.

<p>(A) Peptide pools containing the predicted CD4⁺ T cell epitopes (NAE and AE forms) were tested among HIV seronegative individuals (SN = 10), non-controllers (NC = 14), and controllers (C = 14) in an IFN-γ ELISpot assay. The magnitude of IFN-γ response (SFC/10⁶ PBMC) for all three groups is shown. Each dot represents a response to a single peptide pool, the dotted line demarcates the threshold for a positive ELISpot response (>50 SFC/10⁶). Mann-Whitney U test was used to calculate statistical significance, with error bars representing the SEM. (B) The percentage of patients responding to single peptide (NAE and AE forms) stimulations encompassing the 29 unique HLA-II associated polymorphic sites (shown by the numbering position within each protein, X-axis) as measured in an IFN-γ ELISpot assay is indicated for controllers (middle panel) and non-controllers (right panel).