Additionally, human regulatory T cell -derived IL35 is required for the conversion of human conventional cluster of differentiation 4+Foxp3_ T cells into induced T regulatory 35 cells, which then promote the generation of more induced T regulatory 35 cells via Interleukin 35 secretion, resulting in infectious tolerance (18). In addition, Interleukin 35 has been shown to suppress the T helper (Th) cells Th1 and Th17.