The ability of human FDCs to present sAg to T cells. Highly purified autologous tonsil T cells were obtained that failed to proliferate in response to sAg without adding APCs. Varying numbers of FDCs were cultured with 105 autologous tonsil T cells and SEB at 100 ng/mL for 3 days. Tritiated thymidine uptake was measured during the last 24 hours of culture. Each bar represents the mean cpm + SEM of three independent experiments, and is expressed as a percentage of the response generated when B cells were used at a 1:5 ratio (maximum proliferative response). Cpm from cultures containing only T cells ranged from 272 to 522. FDC significantly induced T-cell proliferation, compared to cultures without APC, at 1:20 and 1:80 ratios by ANOVA and Tukey’s analysis.
