Figure 4.

IFN-γ-producing cells in the BAL at early and late time points. The BAL populations were pooled from five mice, stimulated for 6 hr with peptide in the presence of Brefeldin A, then stained for CD8 and IFN-γ and analyzed by flow cytometry. The control values (no peptide or irrelevant peptide) were always <0.5%, as was the MHV-68 peptide-specific response of BAL cells from C57BL/6J mice infected with influenza A/X31 (not shown). Equivalent results were obtained in five further experiments.