The production of transforming growth factor beta (TGF-β) and IL-10 by regulatory B cells can inhibit the differentiation and activity of tumor-directed CD8+ T cells, Th1 cells and NK cells while promoting the expansion of FoxP3hi CD4+ regulatory T cells by MHC class II-mediated presentation of tolerizing epitopes46. The gene discussed is TGFB1; the disease is neoplasm.