CXCL9 and infection: However, there was an increase over time in circulating IFN-γ and MIG (CXCL9, a monokine induced by IFN-γ), both members of the type II interferon signaling pathway, which peaked between days 3 and 9 post-infection, and returned to basal levels by day 28 post-infection (Fig. 3B).