New CD4 + and CD8 + T Cell Responses Induced in Chronically HIV Type-1-Infected Patients After Immunizations with an HIV Type 1 Lipopeptide Vaccine

We showed that an anti-HIV lipopeptide vaccine injected to HIV-uninfected volunteers was well tolerated and able to induce a specific CD4⁺ and CD8⁺ T cell responses. The same vaccine was injected in HIV-1 chronically infected patients controlled by HAART to evaluate its immunogenicity. In this trial, 24 patients were immunized three times with a mixture of six lipopeptides (Nef 66–97, Nef 117–147, Nef 182–205, Gag 183–214, Gag 253–284, and Env 303–335) at 0, 3, and 6 weeks. We studied the HIV-1-specific CD4⁺ T cell proliferative responses. The IFN-γ secretion by activated CD8⁺ T cells was evaluated, using an ex vivo ELISpot assay and 60 CD8⁺ T cell epitopes derived from the vaccine. Before immunization (W0), anti-HIV CD4⁺ T cell responses to Gag, Nef, and Env large peptides were detected in 7/23 (30%) analyzable patients. After three injections, 17/23 (74%) patients had a proliferative response and 16 of them induced new specific CD4⁺ T cell responses. At W0, CD8⁺ T cell responses to HIV-1 epitopes were detected in 6/23 (26%) patients. After vaccination, 16/23 (70%) patients showed CD8⁺ T cell responses and 13 of these patients induced new T cell responses to 25 different HIV-1 epitopes. These HIV-1 epitopes were detected in patients with various HLA class I molecules (HLA-A2, -A3/A11, -A24, -B7 superfamily, -B8), as found in the majority of the white population. Lipopeptides induce new anti-HIV T cell responses in vaccinated infected patients and could be used as a new immunotherapy strategy. The majority of these responders induced specific new CD4⁺ and CD8⁺ T cell responses.