MONOCLONAL-ANTIBODY 2F4 11 RECOGNIZES THE ALPHA-CHAIN OF A PORCINE BETA-2 INTEGRIN INVOLVED IN ADHESION AND COMPLEMENT-MEDIATED PHAGOCYTOSIS/

The characterization of a new mAb, named 2F4/11, specific for porcine myelomonocytic cells is described. This mAb immunoprecipitates a non-c ovalently linked heterodimer of 155 000/95 000, which is expressed by granulocytes, monocytes and tissue macrophages but not by lymphocytes, erythrocytes or platelets. Immunoblot analysis localizes the 2F4/11 e pitope on the largest subunit of the heterodimer. Mab 2F4/11 is able t o block phagocytosis of complement-opsonized zymosan particles by PMN granulocytes and alveolar macrophages, as well as adherence to plastic surfaces of PMA-activated PMN. Together, these results suggest that m Ab 2F4/11 recognizes the CD11b or a chain of the porcine complement ty pe 3 receptor (CR3).