Expression, Modulation And Function Of A Novel Inducible Adhesion Molecule PTA1 On Human Endothelial Cells

Platelet and T cell activation antigen 1 (PTA1) was initially described as TLiSA1 (T lineage specific activation antigen 1) in 1985, and was renamed as PTA1 in 1989 since it also expressed on platelet. PTA1cDNA was cloned in 1997 and showed to be a novel member of immunoglobulin superfamily(IgSF) with the unusual structure of two V domains only within the extracellular region of this molecule. It was found that PTA1 was mainly expressed on activated T cells, NK cells, platelets and megakaryocyte lineage. Moreover, PTA1 expression on PHA-induced T blasts was upregulated by IL-2, TNF-α and PMA and downregulated by TGF-β. PTA1 mAb (Leo-A1) was found to stimulate the activation and aggregation of platelets, to inhibit the differentiation of CTLs and to decrease the cytotoxicity of NK cells in mixed lymphocyte culture. The research on relationship between PTA1 expression and diseases showed that PTA1 might play important roles in platelet function disorders, autoimmune diseases, transplantation, virus infection diseases and tumors. PTA1 ligand was identified on activated T cells, Jurkat cells, Colo 205 and some kind of melanoma cells.Recently we have found that PTA1 was inducibly expressed on LPS-activated human umbilical vein endothelial cells(HUVECs). To explore the distribution and...