infected WT, CD8−/− (lacking CD8 T cells), MHC-II−/− (lacking CD4 T cells), muMT (lacking B cells), and Rag1−/− mice and compared viral RNA levels in the LFRT at day 12 p.i. While WT and muMT mice completely cleared the infection, viral RNA was detectable in most of the CD8−/− and MHC-II−/− animals (Fig. 1c). This evidence concerns the gene CD4 and infection.