SFTPA2 and infection: In response to infection alone, we observed (a) no gene-specific survival SP-A1 = SP-A2 = KO (male and female combined); (b) variant-specific survival SP-A2 (1A0) > 1A3 = 6A2 = 6A4 (male and female combined); (c) Sex differences in survival in SP-A1 (6A2) mice, with females showing a better survival that males; but no sex difference in SP-A2 (1A0, 1A3), SP-A1 (6A4), and KO mice.