CD4 and infection: We observed a similar increase in serum NS1 levels over the first 7 days p.i. Between days 10 and 15 p.i. NS1 levels in the control group declined, whereas levels in the CD4-depleted group continued to increase and peaked by day 15 p.i. This suggests that the lack of CD4+ T cells enhances DENV2 replication and NS1 levels in circulation, further confirming a role for CD4+ T cells in viral clearance during a primary infection.