IFNAR1 and Splenomegaly: To identify how IFN-I functions on antitoxoplasmosis immunity, particularly for intraperitoneal infection using PRU strain, we first infected WT and Ifnar−/− mice with PRU tachyzoites and found that the absence of the interferon-α/β receptor (IFNAR) could rescue host survival and weight loss during T. gondii infection, which was also presented with fewer parasites load, slighter splenomegaly, and lower SNAP scores compared to WT mice (Fig. 5A to D, Fig. S4A to C).