FIG. 7.

Secondary effector cells in the lung become increasingly nonfunctional over time following infection with SV5. BALB/c mice were infected i.n. with 10⁶ PFU of WT rSV5. After d40 postinfection, mice were challenged by i.n. administration of 10⁷ PFU of WT rSV5. Lung cells were either stained with M_285-293/L^d tetramer or stimulated with 1 μM M_285-293 peptide to assess IFN-γ production as described for Fig. 1. As a negative control, cells were stimulated in the absence of M_285-293 peptide. The numbers represent the percentages of CD8⁺ T cells that were either tetramer positive or IFN-γ⁺.