CCL2 and infection: Somewhat intriguingly, our data revealed that IFN-I signaling regulated the sequential recruitment of CD11b+Ly-6Chi monocytes followed by NK cells, which was closely associated with the cascade response of CCL2 and CCL3 production in mucosal tissues; i.e., CD11b+Ly-6Chi monocyte infiltration peaked at around 24 h after infection, whereas NK cell infiltration peaked at 48 h post-infection (pi).