Regulatory T cells (Tregs) play a role in inhibiting excessive immune responses and preventing autoimmune diseases by producing transforming growth factor-beta (TGF-β). The proprotein encoded by transforming growth factor-beta (TGF-β), known as latency-associated peptide (LAP), can be cleaved by the enzyme furin to release TGF-β latency-associated peptide. Subsequently, it can form a complex by binding with latent TGF-beta binding proteins (LTBPs). Additionally, it can also form a complex with glycoprotein A repetitions predominant (GARP or LRRC32), which is highly expressed on the surface of Tregs, to release inactive TGF-β into the extracellular matrix (ECM) or accumulate it on the cell surface, with the latter having a stronger binding capability than the former.Subsequently, the integrin activates the GARP-proTGFβ complex, forming active TGF-β. Integrin αvβ6, a transmembrane heterodimer composed of α and β subunits non-covalently bound, binds LAP through its high affinity binding site RGD LXXL on the protein structure, and then activates latent TGF-β.The GARP Latent TGFB1 Reporter HEK-293 Cell Line fromHEK-293 cells that stably express human GARP gene, Latent TGFβ, and TGF-β inducible luciferase reporter genes. When co-cultured with αvβ6 HEK-293 Cell Line, TGF-β is cleaved by αvβ6 into the culture medium, binds to TβRI and TβRII receptors, and activates the expression of luciferase genes mediated by transcription factors. However, the addition of blocking antibodies against GARP/αvβ6 inhibits the activation of TGF-β and downstream signaling pathways activated by it. The extent of the blockade antibody’s impact on the signaling pathway can be assessed by measuring the fluorescent signal.
