IL4 and infection: Similar to WT mice, in the CNS of Rag1−/− mice IFN-α1, IFN-β, TNF, IL-1α, IL-1β, IL-6, and IFN-γ mRNA levels increased following i.c. infection with ZIKV (Fig. 4), and IL-2, IL-3, IL-4, and IL-5 mRNA was not detectable (data not shown).