FIG. 4.

Lymphocyte proliferation assay. BALB/c mice were immunized as outlined in the legend to Fig. 3. T-cell-proliferation responses were measured at week 6. Splenocytes from each mouse group were harvested, pooled, and tested in a standard [³H]thymidine uptake assay by using purified recombinant p24 as antigen. The number above each bar represents standard deviation.