STAT3 and infection: As with the intranasal route of infection (Fig. 1C), flow cytometric analysis of MHV68 YFP-positive splenocytes from intraperitoneally infected animals revealed an approximately 3-fold (P < 0.001) reduction in the percentage of infected B cells that lacked STAT3 (stat3f/f;CD19Cre/+) compared to the levels seen with control stat3f/f B cells (Fig. 4E).