Blood T_FR cells

Follicular regulatory T cells (T_FR cells) are a subset of T_reg cells that are specialized in the control of germinal-center (GC) and antibody responses. In Science Immunology, Graca and colleagues investigate the origin and function of the little-known blood counterpart of GC-resident T_FR cells. They find that in blood from human donors, there are more T_FR cells, defined as CXCR5⁺FOXP3⁺, in those with Sjögren syndrome or after vaccination against seasonal influenza virus, and that these cells correlate with antibody production. Much like conventional T_reg cells, blood T_FR cells can suppress T cell responses in vitro, but unlike GC T_FR cells, they do not seem to specialize in the suppression of antibody responses. Furthermore, unlike other T_reg cell populations, they have a predominantly naive phenotype. Developmentally, blood T_FR cells are generated in secondary lymphoid tissue from GC precursor cells but exit into the blood before differentiating into fully functional T_FR cells.

Sci. Immunol. (11 August 2017) doi:10.1126/sciimmunol.aan1487