Figure 1.

Generation of FVIII-specific CD4 T cells from healthy individuals. CD4 T-cell lines were generated as described in Material and Methods. (A) FVIII-specific T-cell lines generated from donor #329. (B) Cross-reactivity analysis between KLH- and FVIII-specific T-cell lines. (C) Frequencies of CD4 T cells specific for FVIII and KLH estimated for 16 healthy blood donors. The frequency of CD4 T-cell precursors was calculated using Poisson distribution according to the following formula: Frequency = −Ln([number of negative wells/total number of wells tested])/(number of CD4 T cells per well). Statistical significance was assessed using the Wilcoxon match-pairs signed rank test. ****P < .0001. Ctrl, control.