In vivo persistence of a HIV‐1‐encoded HLA‐B27‐restricted cytotoxic T lymphocyte epitope despite specific in vitro reactivity

A large number of human immunodeficiency virus type 1 (HIV‐1) specific HLA‐restricted cytotoxic T cell (CTL) epitopes have been mapped, including an HLA‐B27‐restricted immunodominant epitope within p25gag. Accordingly, this segment of the HIV‐1 provirus was amplified by the polymerase chain reaction from DNA derived from fresh uncultured peripheral blood mononuclear cells (PBMC) of four HLA‐B27 HIV‐1‐infected individuals. In all cases the majority of infected PBMC bore sequences encoding the HLA‐B27‐restricted peptide. CTL escape mutants had not accumulated in vivo 8 and 14 months later despite demonstrable CTL activity in vitro. These data emphasize the importance of silently infected lymphocytes in evading immune surveillance.