Follicular helper T cells expressing Blimp1 are specialized for plasma cell differentiation

Abstract

B cells differentiate into antibody-producing plasma cells (PC) and germinal center (GC) B cells under the guidance of specialized CD4+ follicular helper T (TFH) cells. Here, we demonstrate that CD4 T cells require Prdm1 expression for both early PC differentiation and post-GC PC formation. Using dual Blimp1/Foxp3 reporter mice and single cell-indexed analysis, we segregate persistent compartments and expressed transcriptional programs of Blimp1+ CXCR5+PD1hi TFH (referred to here as PC-TFH) from canonical Blimp1- Bcl6+ TFH (GC-TFH) and Blimp1+Foxp3+ TFR immune regulators. Antigen recall expands localized PC-TFH compartments with rapidly divergent antigenspecific memory PC-TFH and GC-TFH programs. Thus, Blimp1 is a central mediator of PC-TFH function producing specialized TFH subsets that co-ordinate with GC-TFH function to establish highaffinity long-lasting protective immunity to vaccines and infection.