Figure 1.

Suppressive mechanisms of Bregs by soluble molecules. (A) IL-10⁺ Bregs inhibit Th1, Th17, and CD8⁺ T cell responses; convert naïve CD4⁺ T cells into regulatory T cell populations; and modulate pro-inflammatory innate cells through the production of IL-10. (B) Likewise, TGF-β⁺ Bregs operate on naïve CD4⁺ T cells to generate FoxP3⁺ Tregs, in addition to induce anergy in CD4⁺ and CD8⁺ T cells. (C) IL-35⁺ Bregs can promote “infectious tolerance” by inducing IL-35-producing Tregs and expanding the generation of IL-35⁺ Bregs. (D) GrB⁺ B cells have been shown to inhibit Th1 and Th17 cell responses and to reduce CD4⁺ T cell proliferation by degrading the TCR ζ-chain. DC, Conventional dendritic cell; GrB, Granzyme B; MΦ, Macrophage; NK, Natural killer cell; NO, Nitric oxide; pDC, Plasmacytoid dendritic cell; TolDC, Tolerogenic dendritic cell; Tr1, Type-1 regulatory T cell.