FIG 1.

Antibody-mediated protection is conferred by IgG. Prior to and throughout secondary infection, immune serum (or a fraction of it) or normal serum was passively transferred to CD4-depleted antibody-deficient mice (n = 5). Following infection, IFU were quantitated from cervicovaginal swabs collected at various time points after secondary infection. The vertical dashed line at day 23 represents the final anti-CD4 injection. For clarity, statistical significance is listed here rather than on the figure: for normal serum versus immune serum, P < 0.01 for days 7, 10, and 14, P < 0.0001 for days 21 through 42, and P < 0.05 for day 49; for normal serum versus purified IgG, P < 0.01 for days 7 and 14, P < 0.0001 for days 10 and 21 through 42, and P < 0.05 for day 49. There were no statistical differences between normal serum and Fab serum, normal serum and IgG-depleted serum, or immune serum and purified IgG at any time point.