Distribution And Function Of The Mouse Leukocyte Differentiation Antigen Pta1

Leukocyte differention antigens, the most important surface markers of immune cells, are named as CDs by the International "Leukocyte Differention Antigen Workshop. Most CD molecules have homologues in other mammalians, of which mouse is the most intensively studied. The studies on murine and human CDs have benefited each other, and gave great promotion to the study on leukocyte differention antigens.Platelet and T cell activation antigen 1(PTA1) is a novel leukocyte differention antigen initially found on the surface of cytotoxic T lymphocyte (CTL) generated from mixed lymphocyte culture, and can exert influence on CTL differention. PTA1 was later found on activated T cell, NK cell, platelet and endothelial cells, with participation in cell differention and platelet coagulation. PTAl was also found involved in the ongoing of platelet abnormality, autoimmune diseases, and graft-versus-host diseases.PTA1 cDNA was cloned in 1997, which confirmed PTA1 as a novel leukocyte differention antigen belongs to immunoglobulin superfamily with two immunoglobulin domains within the extracellular region. Gibbon and monkey PTA1 .cDNAs were cloned the next year, and exhibit homology of 93～95% with that of human. These results indicate that PTA1 is highly conserved during evolution.Because of the importance of mouse as experimental animal and the progress on murine leukocyte differentiation antigens, herein murine PTA1 was systematically studied in its expression, function and gene.Firstly, PTA1 was found expressed on murine tissues by immunofluorescence staining and in situ hybridization. PTA1 expression was found restricted within lymphoid organs, especially in the T cell zones. PTA1 was not found in heart muscle, liver, lung, kidney and skeletal muscle.Next, the expression of murine PTA1 was studied in cell level by immunofluorescence staining and flow cytometry. PTA1 was found expressed mainly on murine thymocytes, splenocytes and T lymphocytes. No PTA1 expression was found in fibroblast, mast cell or macrophage cell lines. Murine PTA1 expression in T cells can be induced by phytohemagglutinin (PHA) and phorbol ester (PMA) , and...