FIG. 3.

Epitope-specific CD8⁺ T-cell populations in BAL fluid in relation to the total of virus-specific IFN-γ-producing CD8⁺ T cells during a primary and secondary influenza virus infection. B6-P^−/−, B6-FasL^−/−, or control B6 mice were infected as described in the legend for Fig. 1, and BAL cells were isolated 10 days after primary (A) or secondary (B) infection. The percentage of antigen-specific CD8⁺ T cells was assessed by staining with MHC tetramers (indicated) and antibody against CD8, and total numbers of virus-specific CD8⁺ T cells producing IFN-γ after stimulation with virus-infected DC2.4 cells were determined by concurrent analyses (bottom panels). The percentage of CD8⁺ T cells staining positive by MHC tetramer or producing IFN-γ are indicated in the lower corners of the corresponding panels. Plots shown are gated for live cells.