Six epitopes reacting with human cytotoxic CD8+ T cells in the central region of the HIV-1 NEF protein

In order to identify the target epitopes recognized by specific CTL in the NEF protein of HIV-1, 33 peptides derived from the HIV-BRU sequence were tested with NEF-specific CTL generated from HIV-seropositive donors. Six different epitopes were identified and several points were remarkable: 1) They were all located in two regions of the central part of the NEF protein corresponding to residues 73 to 94 and 113 to 147, respectively. 2) The CTL issued from a single donor could recognize several peptides of the NEF protein. 3) Some of these peptides could be recognized in association with at least two or three different HLA class I molecules. 4) Two different overlapping epitopes were present in a relatively short sequence of 15 amino acids. These results suggest that multiple epitopes corresponding to different HLA restrictions could coexist in a relatively small region of the NEF protein. The implications of these results in vaccine strategies using synthetic peptides bearing CTL epitopes are discussed.