FIG. 2.

Presence of anti-Ag85-specific antibodies in the sera of CD4⁺-T-cell-reconstituted CD4^−/− mice following vaccination. WT and CD4^−/− mice were vaccinated either with Ag85B DNA or control (ctrl) DNA three times at 3-week intervals. In parallel, CD4^−/− mice were given an AT with 2.5 × 10⁶, 5 × 10⁶, or 20 × 10⁶ CD4⁺ T cells and vaccinated with Ag85B DNA. Blood samples were obtained from mice 3 weeks after the third vaccination dose, and sera were tested for the presence of Ag85-specific antibodies by ELISA. Optical density values were converted to concentrations by using a monoclonal antibody (TD-17) of a known concentration as a standard. Five or six mice were tested in each group. Results are shown as means ± standard deviations. Following reconstitution with 5 × 10⁶ and 20 × 10⁶ CD4⁺ T cells, significant levels (P, <0.05 and <0.01, respectively) of vaccine-specific serum antibodies were detected compared to vaccinated CD4^−/− mice.