Creating HIV-1 reverse transcriptase cytotoxic T lymphocyte target structures by HLA-A2 heavy chain modifications

Vigorous HIV-1-specific CD8(+) cytotoxic T lymphocyte (CTL) responses play an important role in the control of HIV-1 replication and the induction of a strong, broadly cross-reactive CTL response remains an important goal of HIV vaccine development. It is known that the display of high levels of cla ss I MHC-viral peptide complexes at the cell surface of target cells is nec essary to elicit a strong CTL response. We now report two strategies to enh ance the presentation of defined HIV-1 epitope-specific CTL target structur es, by incorporating subdominant HIV-1 reverse transcriptase (RT) CTL epito pe sequences into the human class I MHC molecule HLA-AS. We show that eithe r incorporation of HIV-1 CTL epitopes into the signal sequence of HLA or te thering of epitopes to the HLA-A2 heavy chain provide simple ways to create effective CTL target structures that can be recognized and lysed by human HLA-AP-restricted RT-specific CD8(+) CTL. Moreover, cells expressing these epitope-containing HLA-AP constructs stimulated the generation of primary e pitope-specific CTL in vitro, These strategies offer new options in the des ign of plasmid DNA-based vaccines or immunotherapeutics for the induction o f CTL responses against subdominant HIV-1 epitopes.