Detection, separation and characterization of organ specific antigens of human thrombocytes

Abstract

By means of rabbit anti-human thrombocyte antibodies, two organ specific antigens of human thrombocytes were detected. Both antigens were found to be specific for human thrombocytes and did not cross-react with thrombocyte antigens of other species. Separation and purification of the antigens were achieved by ion exchange chromatography and polyacrylamide gel electrophoresis. Production of monospecific antisera against each antigen separately was obtained by using purified antigen preparations for immunization. Physicochemical studies showed that both antigens are thrombin resistant, trypsin sensitive, and denatured at temperatures of 100° but not at 56°. One antigen is a glycoprotein with an α-globulin electrophoretic mobility and a molecular weight of approximately 1.07–1.17 × 10⁵, while the other is a protein with faster mobility in the post-albumin region and a molecular weight of 2, 8–3, 0 × 10⁴. Both antigens are present in soluble form in the cell sap as well as insoluble components in the cell membranes but only one antigen, the glycoprotein, could be solubilized from the platelet membranes by sodium dodecyl sulphate and pyridine treatments.