Inhibition of memory B-cell restimulation is not mediated by FVIII-specific T cells. ELISPOT analysis of newly formed anti-FVIII APCs after 6 days of culture. CD138^– spleen cells (obtained from hemophilic mice immunized with human FVIII) were depleted of T cells and mixed in a ratio of 1:2 with either (A) T cells obtained from a 3-day culture of CD138^– spleen cells (obtained from hemophilic mice immunized with FVIII, culture in the presence of 20 μg/mL FVIII) or (B) T cells obtained from hemophilic mice immunized with 3 doses of OVA. Two aliquots of each cell mixture were obtained and cultured in the presence of FVIII or FVIII and OVA at the concentrations indicated. As a negative control, CD138^– spleen cells (obtained from hemophilic mice immunized with FVIII) depleted of T cells, were cultured in the presence of 0.01 μg/mL FVIII. Presented is a typical experiment. Spleens of 5 mice were pooled for cell preparation. All experiments (n = 3) gave similar results.