FIG. 4.
HLA-DR-dependent recognition of bacterial superantigens by CD56+ T cells. CD56+ T cells (2 × 105 cells/well) were cultured (37°C, 5% CO2) with gamma-irradiated (1,500 rads) autologous PBMC (2 × 105 cells/well) in the presence of SEA (0.36 nM) and various amounts of rabbit anti-HLA-DR or control antibody. After 60 h of culture, cells were pulsed with [3H]thymidine (1 μCi/well) for 10 h. Cells were harvested, and cellular proliferation was assessed by measuring incorporated radioactivity by liquid scintillation. Open symbols (circles and triangles) represent CD56+ T cells, autologous PBMC, and antibody; closed symbols (circles and triangles) represent CD56+ T cells and antibody without APC. The data are presented as mean counts per minute ± standard errors of the means of triplicate wells. Results presented in the figure were representative of three experiments.