Previous studies have reported that TLR2 plays an important role in early recognition of M. avium by macrophages, and it has been reported that TLR2 is upregulated after MAP bacteria infect macrophages for 2 h (Machugh et al., 2012); however, no significant difference in TLR2 expression after 6 h of infection was observed in this experiment. Here, TLR2 is linked to infection.