FIG. 3.
Systemic (spleens) and local (lymph nodes) CD8+ T-cell primary responses. Three mice per group of young adult (8-week-old) or aged (18-month-old) mice were primed i.n. with 2 × 105 PFU of ca Sing (black bars) or ca Sing-IL-2 (hatched bars). At day 10 p.i., single-cell suspensions obtained from the spleens (a) or lymph nodes draining the respiratory tracts (b) of mice were assessed for influenza virus NP peptide-specific IFN-γ-secreting CD8+ T cells in an ELISPOT assay. The data shown are the mean numbers of antigen-specific IFN-γ-secreting cells ± standard errors of the means for triplicate cultures. The differences between the ca Sing and ca Sing-IL-2 responses are significant for both groups, young adult and old mice (P < 0.01).