We used RT-PCR to confirm IL-21-induced expression of Gzma and Gzmb mRNAs in the lung at 7 hr after infection (Figure 1H and I), and IL-21-induced granzyme B and IFNγ protein production was detected by ELISA in bronchoalveolar lavage fluid at 7 hr after infection (Figure 1J and K). This evidence concerns the gene IFNG and infection.