IFNA1 and infection: Moreover, the expression of IP-10 encoded by an IFN-responsive gene was significantly impaired in Card9−/− mice on day 4 (Fig. 1D), albeit no significant reduction was seen in either Type I or Type II interferons, suggesting that synergistic signals of interferons and various cytokines/chemokines are required for the higher expression of IP-10 at an early phase of infection.