Induction of CTL responses by peptide pulsed DC or freshly isolated PBMNC. PBMNC from a HLA A2 positive donor were cultured with the indicated combinations of cytokines for 7 days. 5 × 10⁵ DC pulsed with the synthetic peptides derived from pol HIV-1 reverse transcriptase were used as APC to induce an MHC class I–restricted CTL response in vitro. Cytotoxic activity of induced CTL was determined in a standard ⁵¹Cr-release assay using T2 cells as targets pulsed for 2 hours with 25 μg of the cognate HIV (closed symbols) or irrelevant IMP peptide (open symbols). Data are from one representative experiment out of three.