S1PR1 and infection: To determine if the recruitment of lymphocytes from draining lymph nodes was necessary for lung B cell accumulation after the second Sp19F infection, we administered the sphingosine-1-phosphate receptor 1 (S1P1R) inhibitor FTY720 or vehicle treatment intraperitoneally (i.p.)before, during, and after the second infection (Figure 3A) and used flow cytometric analysis to quantify B cell populations at 3 days post second infection (dpsi; corresponding to day 10 in Figures 1, 2), 7dpsi (corresponding to day 14), and 28dpsi (corresponding to day 35).