Extracellular matrix protein 1 promotes follicular helper T cell differentiation and antibody production

Significance T FH cell differentiation and antigen-specific antibody production is critical for humoral responses. In this work, we show that extracellular matrix protein 1 (ECM1) is a critical positive regulator in T-follicular helper (T FH ) differentiation by repressing IL-2–STAT5–Bcl6 signaling pathway. Importantly, ECM1 effectively enhanced T FH differentiation, germinal center responses, and neutralizing antibody production both in antigen-immunized conditions and influenza infection, which indicate ECM1 may serve as a positive regulator for humoral responses in vivo.