Lack of SP-A, however, blunted the Th1 immune response to SP-D-resistant X-79Δ167 mutant, as indicated by suppression of IFNγ with a marginal reduction in survival with increasing inoculum dose, and no difference in viral burden (112) when compared to the induction of IFNγ after infection with the H3N2 Phil82 strain shown by Levine et al. This evidence concerns the gene SFTPA2 and infection.