TLR2 and infection: Xiao et al. [45] found that TLR2 and TLR4 were up-regulated in pigs at 28 DPI with M. pneumoniae. Yoshihiro [46] infected porcine alveolar macrophages with M. hyopneumoniae in vitro and found that TLR2 and TLR6 were up-regulated at 48 h after infection.