FIG. 6.

Antigen-specific T-cell proliferation. Activation of B cells by an increased level of intracellular cAMP enhances their ability to present PPD or TT in the autologous T-cell response. B cells derived from a PPD or TT responder donor were stimulated with 2.5 μg/ml of CpG ODN 2006 and 50 U/ml IL-2 in the presence of PPD or TT and treated as indicated or left untreated (NT) for 3 days. Cells were then irradiated and cocultured with autologous PBMC labeled with CFSE at different B cell/PBMC ratios. After 5 days of coculture cells were collected and stained with anti-human CD4 or anti-human CD8 MAb. The levels of PBMC, CD4⁺, and CD8⁺ T cell proliferation were evaluated by FACS analysis. The error bars indicate standard deviations for duplicates. PBMC TOT, total PBMC.