IL-12 drives the differentiation of human T follicular regulatory cells.

T follicular regulatory (T) cells can counteract the B cell helper activity of T follicular helper (T) cells and hinder the production of antibodies against self-antigens or allergens. A mechanistic understanding of the cytokines initiating the differentiation of human regulatory T (T) cells into T cells is still missing. Herein, we report that low doses of the pro-T cytokine interleukin-12 (IL-12) drive the induction of a T cell program on activated human T cells while also preserving their regulatory function.