TLR2 and pneumonia: Moreover, although histopathological analysis of lung tissue showed diminished lung inflammation in TLR2 KO mice during the early course of infection with S. pneumoniae PLN, which is in line with a TLR2-dependent immune response, during the later phase of pneumonia lung inflammation of TLR2 KO mice was enhanced compared with WT mice, which corresponded with the higher bacterial loads.