Regulation of the germinal center reaction by Foxp3 follicular regulatory T cells

Abstract

Follicular helper T (T FH) cells participate in humoral responses providing selection signals to germinal center B cells. Recently, expression of CXCR5, PD-1, and the transcription factor Bcl-6 has allowed the identification of T FH cells. We found that a proportion of follicular T cells, with phenotypic characteristics of TFH cells and expressing Foxp3, are recruited during the course of a germinal center (GC) reaction. These Foxp3 + cells derive from natural regulatory T cells. To establish the in vivo physiologic importance of Foxp3 + follicular T cells, we used CXCR5-deficient Foxp3 + cells, which do not have access to the follicular region. Adoptive cell transfers of CXCR5-deficient Fox..