TLR4 and infection: Meanwhile, by analyzing the gene expression profiles in the lung of C57BL/6 mice (resistant to bacterial transmission), 129/SVJ mice (susceptible), C3H/HeJ mice (susceptible and TLR4 signal deficient) and their respective control strains C3H/HeN mice (moderately resistant), it was found that the most significant number of TLR4-dependent induced genes were expressed in C57BL/6 and C3H/HeN mice after infection with K. pneumoniae.