FIG. 2.

Cytotoxic activities of the seven responder macaques. Anti-peptide CTL lines were obtained by pulsing for 2 h macaque PBMCs (10 × 10⁶ cells/ml) with a mixture of the five Nef and two Gag free long peptides (10 μM each) corresponding to the immunizing lipopeptides. The cells were then washed and resuspended (10⁶/ml) in complete medium and incubated in 24-well microtiter plates. After 3 days of incubation, IL-2 was added to each well (10 IU/ml). On days 7 and 14, effector cells were washed and diluted to 10⁶/ml, placed in new plates, and stimulated with irradiated peptide-pulsed (10 μM each) autologous PBMCs (10 × 10⁶/ml) for 2 h and then diluted to 10⁶/ml in complete medium containing 20 IU of IL-2/ml (effector/stimulator ratio, 1:1). A CRT was performed after the third stimulation of CTL lines. The target cells were autologous B-LCLs (immortalized by the herpesvirus papio) alone or incubated overnight with various long peptides (10 μM/ml). The CRT was considered positive if the specific ⁵¹Cr release observed in the presence of peptide-pulsed target cells exceeded by 10% that observed for B-LCLs without peptide at two effector/target (E/T) ratios. Only the positive cytotoxic responses against peptide-sensitized target cells of the seven responder macaques are shown.