The immunoreceptor SLAMF8 promotes the differentiation of follicular dendritic cell‐dependent monocytic cells with B cell‐activating ability

Abstract

Follicular dendritic cells (FDCs) play a crucial role in generating high‐affinity antibody‐producing B cells during the germinal center (GC) reaction. Herein, we analysed the altered gene expression profile of a mouse FDC line, FL‐Y, following lymphotoxin β receptor stimulation, and observed increased Slam‐family member 8 (Slamf8) mRNA expression. Forced Slamf8 expression and SLAMF8‐Fc addition enhanced the ability of FL‐Y cells to induce FDC‐induced monocytic cell (FDMC) differentiation. FDMCs accelerated GC‐phenotype proliferation in cultured B cells, suggesting that they are capable of promoting GC responses. Furthermore, a pulldown assay showed that SLAMF8‐Fc could bind to SLAMF8‐His. Overall, the homophilic interaction of SLAMF8 promotes FDMC differentiation and SLAMF8 might act as a novel regulator of GC responses by regulating FDMC differentiation.