FIG. 4.

TCRs and not cytokine signals provide minimal activation necessary for HIV replication. (A) Replication of wild-type HIV in EC-T-cell cocultures 9 days postinfection treated with the indicated blocking antibodies (dark bars) or isotype controls (light bars) as assessed by p24 measured in the supernatant by ELISA. (B) IL-2 measured in the supernatant of infected T cells after 1 day of coculture with ECs in the presence of various doses of PHA-L or vehicle alone. (C) Cell-free virus measured in the supernatant of infected EC-T-cell cocultures on day 7 postinfection as assessed by p24 measured in the supernatant by ELISA. (D and E) FACS analyses of CD4⁺ T cells cocultured with untreated ECs in the presence of (D) 0 μg/ml and (E) 0.063 μg/ml of PHA-L. The boxes identify the CFSE^high p24^high cells. Note the expansion of CFSE^high p24^high cells in the wild-type-infected cultures in the presence of 0.063 μg/ml of PHA-L. The data in panels A to E are from one of three experiments with similar results. The error bars indicate standard deviations.