Characterization of canine platelet P-selectin (CD 62) and its utility in flow cytometry platelet studies

1. P-selectin (PADGEM, GMP140, or CD62) a member of lectin-like adhesive proteins is expressed on the surface of activated degranulated canine platelets and is the calcium-dependent receptor for leukocyte adhesion. 2. The electrophoretic mobility of P-selectin, by Western blot analysis and immunoprecipitation from radiolabeled membranes of canine and human platelets, was similar or identical and immunocytochemical studies localized P-selectin in internal vesicles similar to the alpha granule localization in human platelets. 3. Two antibodies to human P-selectin KC4.1 and AC1.2 crossreacted with canine platelets whose surface binding, in response to agonists thrombin, calcium ionophore (A23187), phorbol esters and ADP, was similar. 4. Anti-P-selectin antibodies in conjunction with crossreacting anti-GPIIb/IIIa antibodies (A2A9, 7E3, RUU-PL7F12) enables the analysis of activated platelets, platelet-derived microparticles and platelet-leukocyte interactions in canine models by flow cytometry.