CD4-positive helper T cell regulatory T cell Tr1 cell CD4-positive alpha-beta T cell with regulatory function that produces IL-10. T-regulatory T cell type 1 These cells are reportedly induced by IL-10 and are capable of producing IFN-gamma, IL-5, IL-10, and TGF-beta.) Tr1 T cell Tr1 T lymphocyte Tr1 T-cell Tr1 T-lymphocyte cell