IFNAR1 and infection: However, in relation to MRSA-only infections of WT and Ifnar1−/− mice, treatment with exogenous IL-13 of MRSA-only infected WT mice reduced bacterial burden within 24 h, but it did not affect the ability to clear MRSA from lungs of MRSA-only-infected Ifnar1−/− mice (see Fig. S1A and B in the supplemental material).