Anti-FVIII antibody formation and restimulation of FVIII-specific memory B cells. (A) F8^−/− mice received 4 doses (weeks 1-4) of rhFVIII IV or rhFVIII+VWF-12 subcutaneous (200 IU/kg, 20 mice per group). Anti-FVIII IgG titers were determined by ELISA. Results are shown for individual mice as scatter plots on a logarithmic scale. Data were analyzed by 2-way ANOVA with Bonferroni correction for multiple comparisons. ****P < .0001. (B) Splenocytes from rhFVIII-immunized mice were restimulated with rhFVIII (1 or 3 IU/ml) in the absence or presence of VWF-12 in different molar ratios. Mean ± SD are shown from 2 independent experiments (group 1 and 2), each with 3 mice per group and triplicate analysis of pooled cells.