A conserved HLA B13-restricted cytotoxic T lymphocyte epitope in Nef is a dominant epitope in HLA B13-positive HIV-1-infected patients.

We report on the first HLA B13-restricted minimal cytotoxic T lymphocyte (CTL) epitope RQDILDLWI (RI9, amino acids 106-114 in HIV-1 Nef). In most patients the frequency of RI9-specific CTL exceeded the number of CTL against other epitopes, indicating that RI9 is a dominant epitope in HLA B13-positive patients. Targeting this conserved Nef epitope may be an important factor for the published association of HLA B13 with a favourable course of HIV-1 infection.