CHARACTERIZATION OF THE PORCINE HOMOLOG TO HUMAN PLATELET GLYCOPROTEIN IIB-IIIA (CD41 CD61) BY A MONOCLONAL-ANTIBODY/

Human gpIIb-IIIa or CD41/CD61 is a Ca2+-complex dependent heterodimer, abundant on platelets, that plays a key role in hemostasis. This repo rt describes a murine monoclonal antibody, JM2E5, able to recognize an d immunoprecipitate the gpIIb/IIIa surface glycoprotein from porcine p latelets. Immunoprecipitation analysis showed an antigen molecular wei ght of 115 and 85 kDa under nonreducing conditions, and of 110, 100 an d 25 kDa under reducing conditions. Immunohistochemistry analyses of f rozen sections from several porcine lymphoid organs gave specific stai ning on platelets. EDTA treated platelets were studied by flow cytomet ry indicating that the epitope recognized was Ca2+-complex independent . Western-blotting experiments with porcine platelet extracts gave an antigen molecular weight of 85 kDa under nonreducing conditions, thus localizing the epitope recognized by JM2E5 on the complex light chain gpIIIa or CD61. JM2E5 was also cross-reacting with human, bovine and h orse platelets, as shown by flow cytometry, This mAb would allow furth er studies on this important adhesion molecule on horses, ruminants an d pigs. and it should be especially useful as a general anti-porcine p latelet reagent.