FIG 3.

Plasma viral loads and FV-neutralizing Ab titers in AID-deficient CB6F₁ mice immunized with peptide i. AID^−/− and WT CB6F₁ mice were either immunized with 10 μg per mouse of peptide i plus CFA or given CFA alone and were challenged with 150 SFFU of FV 3 weeks later. (A and B) Plasma viral loads detectable as infectious foci and as F-MuLV RNA copy numbers and the numbers of F-MuLV infectious centers in the spleen were determined at 2 weeks after FV inoculation as described for Fig. 1 and elsewhere (5, 8). Each closed circle represents the actual value obtained from an individual mouse, and the horizontal bars in panel B indicate the mean values for each group. The dashed lines in panel A indicate the limit of detection at 200 FFU/ml or 7,272 copies per ml plasma. Significant differences were detected by Mann-Whitney or Wilcoxon signed-rank tests for non-Gaussian distributions or by Welch's t test for Gaussian distributions (*, P < 0.05; **, P < 10⁻⁵). (C) Serum titers of virus-neutralizing IgM or IgG were measured at the indicated time points for a period of 4 weeks after FV inoculation as described previously (8, 14). Each data point shows the mean ± SEM calculated with data from five to six mice per group.