Fig. 3.

tipDCs present antigen to CD8⁺ T cells in the lungs. (A) CCR2^−/− animals have significantly fewer CD8⁺ T cells specific for the influenza D^bPA_224–233, K^bPB1_703–711, and D^bPB1-F2_62–70 epitopes. Results are representative of 2 independent experiments (n ≥ 5) and were analyzed by using the two-tailed Student's t test (P values are indicated). (B) There is no statistically significant difference in the number of antigen-specific CD8⁺ T cells between CCR2^+/+ and CCR2^−/− animals in the draining lymph node on day 7 after infection with 10⁵ pfu of x-31. Results are representative of two independent experiments (n ≥ 5) and were analyzed by using the two-tailed Student's t test (P > 0.05 for each comparison). (C) tipDCs isolated from the BAL wash on day 6 after infection present the equivalent of 40 pmol per cell of D^bPB1-F2_62–70 epitope to the D^bPB1-F2_62–70 epitope-specific hybridoma. Bars represent the mean ± SEM of triplicate wells, and the results were analyzed by using the two-tailed Student's t test (P value indicated). (D) tipDCs isolated from the BAL wash of animals infected with the intact x-31 virus (but not the D^bNP_366–374- and D^bPA_224–233-disrupted DKO virus) were sufficient to rescue the D^bNP_366–374 and D^bPA_224–233 epitope-specific CD8⁺ T cell response when transferred into the lungs of CCR2^−/− animals on day 1 after infection (n = 5). Results were analyzed by using a single-factor ANOVA and Tukey's posthoc test (same letter, P > 0.05; different letters, P < 0.05).