CATFISH THROMBOCYTES EXPRESS AN INTEGRIN-LIKE CD41 CD61 COMPLEX/

A thrombocyte-specific antigen was identified in two closely related c atfish, Ictalurus punctatus and Ictalurus furcatus, by monoclonal anti bodies 4-20 and 72. The antibodies immunoprecipitate two noncovalently associated glycoprotein chains of M-r 180,000 and M-r 95,000. Under r educing conditions the M-r 180,000 chain is resolved into M-r 150,000 and 32,000 subcomponents. Analysis of N-terminal amino acid sequences indicates homology of the M-r 95,000 chain with the PS integrin subuni t and homology of the M-r 150,000 chain with the alpha(IIb) integrin s ubunit. These antibodies induce catfish thrombocyte aggregation and al teration of cell shape. The data indicate conservation of the megakary ocyte/platelet-restricted CD41/CD61 complex in bony fish. (C) 1997 Aca demic Press.