Identification of T follicular helper (Tfh) cells by flow cytometry

Abstract

T follicular helper (Tfh) cells are the main T helper (Th) cell subset that provides help to B cells, supporting germinal center induction, affinity maturation, and generation of memory B cells and long-lived plasma cells. Recently, Tfh cells and Tfh-like transition states have also been implicated in the generation of other Th cell subsets, including Th1 and memory Th cells. Tfh cells are generally characterized by their expression of the chemokine receptor CXCR5, the transcription factor BCL6, and the inhibitory molecule PD-1. Here we provide a simple and reliable optimized staining protocol for the identification of murine Tfh cells by flow cytometry. Stained cells can be analyzed directly by flow cytometry. Tfh cell sorting for use in downstream applications is also possible using CXCR5 and PD-1 staining, but intracellular staining for BCL6 is not compatible with live cell recovery.