In summary, we demonstrated for the first time that TcpC suppresses M1 but promotes M2 macrophage polarization by down-regulation of ERK and p38/NF-κB and up-regulation of the Akt/STAT6 signaling pathway, respectively, hereby favoring UPEC to escape from the macrophage-mediated inflammatory anti-infection response (Figure 8). The gene discussed is STAT6; the disease is infection.