Tr1 cells are self or non-self antigen specific and their key role is to induce and maintain peripheral tolerance[1] and suppress tissue inflammation in autoimmunity and graft vs. host disease.
[3][4][5] CD49b belongs to the integrin family and is a receptor for many (extracellular) matrix and non-matrix molecules.
[6] Tr1 cells secrete large amount of suppressing cytokines IL-10 and TGF-β.
[14] Cytolysis indirectly suppresses immune response by reducing numbers of myeloid-origin antigen presenting cells.
Tr1 cells possess huge clinical potential in means to prevent, block and even cure several T cells mediated diseases, including GvHD, allograft rejection, autoimmunity and chronic inflammatory diseases.
[20][21] Transplantation research has shown, that donor Tr1 in response to recipient alloantigens, was found to correlate with the absence of GvHD after bone marrow transplantation, while decreased numbers of Tr1 markedly associated with severe GvHD.
[21] Decreased levels of IL-10 CD4+ producing cells were also observed in inflamed synovium and peripheral blood of patients with rheumatoid arthritis.
[7] Phase I/II of clinical trials of Tr1 cell treatment concerning Crohn's disease have been successful and appear to be safe and do not lead to a general immune suppression.