OASL and infection: Although splenic cDCs and Macs of Oasl1 KO mice produced more IFN-Is than WT mice, pDCs defined as CD11cintB220+CD8+/− were the most dominant cellular source for the sustained, higher IFN-I levels observed in the serum of LCMV-CL-13-infected Oasl1 KO mice at the very early stage of infection: pDCs in Oasl1 KO mice had more than 10-fold higher IFN-I mRNA levels than cDCs and Macs, and pDCs in Oasl1 KO mice had a more than 8-fold higher expression of IFN-I mRNAs than those in WT mice (Fig. 5D).