We have previously shown that intranasal MHV-1 infection of C3H/HeJ mice, which harbor a natural mutation in the gene that encodes toll-like receptor 4 (TLR4) [15], [16], results in increased morbidity and mortality along with severe pulmonary disease as compared to the wild-type C3H/HeN mice [17]. This evidence concerns the gene TLR4 and lung disorder.