biostudies-literatureUnknown111(32)Ise WIn primary humoral responses, B-cell lymphoma 6 (Bcl6) is a master regulator of follicular helper T (TFH) cell differentiation; however, its activation mechanisms and role in memory responses remain unclear. Here we demonstrate that survival of CXCR5(+) TFH memory cells, and thus subsequent recall antibody response, require Bcl6 expression. Furthermore, we show that, upon rechallenge with soluble antigen Bcl6 in memory TFH cells is rapidly induced in a dendritic cell-independent manner and that peptide:class II complexes (pMHC) on cognate memory B cells significantly contribute to this induction. Given the previous evidence that antigen-specific B cells residing in the follicles acquire antigens within minutes of injection, our results suggest that memory B cells present antigens to the coProceedings of the National Academy of Sciences of the United States of America11792-7https://www.ebi.ac.uk/biostudies/studies/S-EPMC4136626biostudies-literatureMemory B cells contribute to rapid Bcl6 expression by memory follicular helper T cells.PMC4136626Inoue TMcLachlan JBIse WKometani KKurosaki TKubo MOkada TfalseMemory B cells contribute to rapid Bcl6 expression by memory follicular helper T cells.In primary humoral responses, B-cell lymphoma 6 (Bcl6) is a master regulator of follicular helper T (TFH) cell differentiation; however, its activation mechanisms and role in memory responses remain unclear. Here we demonstrate that survival of CXCR5(+) TFH memory cells, and thus subsequent recall antibody response, require Bcl6 expression. Furthermore, we show that, upon rechallenge with soluble antigen Bcl6 in memory TFH cells is rapidly induced in a dendritic cell-independent manner and that peptide:class II complexes (pMHC) on cognate memory B cells significantly contribute to this induction. Given the previous evidence that antigen-specific B cells residing in the follicles acquire antigens within minutes of injection, our results suggest that memory B cells present antigens to the co2014-01-01T00:00:00Z2014 Aug2025-04-19T11:21:56.806Z2019-03-27T01:34:17ZS-EPMC41366262507120310.1073/pnas.1404671111