Recombinant Human TGF-beta1 (carrier-free)

TGF-beta1 is synthesized in cells as a 390-amino acid. Furin cleaves the protein at residue 278, yielding an N-terminal cleavage product which corresponds to the latency-associated peptide (LAP), and the 25-kD C-terminal portion of the precursor constitutes the mature TGF-beta1. TGF-beta activators can release TGF-beta from LAP. These activators include proteases that degrade LAP, thrombospondin-1, reactive oxygen species, and integrins avb6 and avb8. Mouse TGF-beta converts naïve T cells into regulatory T (Treg) cells that prevent autoimmunity. Although human TGF-beta1 is widely used for inducing FOXP3+ in vitro, it might not be an essential factor for human Treg differentiation. Th17 murine can be induced from naïve CD4+ T cells by the combination of TGF-beta1 and IL-6 or IL-21. Nevertheless, the regulation of human Th17 differentiation is distinct. TGF-beta1 seems to have dual effects on human Th17 differentiation in a dose-dependent manner. While TGF-beta1 is required for the expression of RORgammat, in human naive CD4+ T cells from cord blood, TGF-beta1 can inhibit the function of RORgammat at high doses. By using serum-free medium, it has been clarified that the optimum conditions for human Th17 differentiation areTGF-beta1, IL-1beta, and IL-2 in combination with IL-6, IL-21 or IL-23.