Figure 5. Tfh cells help the secretion of autoantibody in CD4⁺ T cells/B cells co-cuture in vitro.

(A) Secretion of autoantibody in CD4⁺ T cells/B cells co-cuture system. Peripheral CD19⁺ B cells(1.5×10⁵ cells/well) and CD4⁺ T cells(1.5×10⁵ cells/well) from 6 healthy controls and 6 BP patients were cultured alone or together for 7 days and then the secretion of autoantibody were detected. (B) Secretion of autoantibody in CD4⁺ T cells/B cells co-cuture system after depletion of Tfh or inhibition of IL-21. CD4⁺CXCR5⁺ T cells were cleaved from the co-culture system by sorting on a FACSAria flow cytometer to evaluate the function of Tfh cells in BP autoantibody secretion. The effect of inhibiting IL-21 were examined by adding neutralizing anti-IL-21 polyclonal Ab. CD19⁺ B cells alone or culture with anti-CD3 Ab were the negative control. Results shown are from a representative experiment of three independent experiments. *P<0.05, **P<0.01.