EXPRESSION AND ROLE OF ADHESION MOLECULE CD18 ON BOVINE NEUTROPHILS

Expression of CD18 on bovine neutrophils in response to stimulation by zymosan activated serum (ZAS) and phorbol myristate acetate (PMA) and the effects of monoclonal antibodies (MAB) recognizing CD18 or bovine neutrophil surface antigens (S2G8 and S5F8G10) on adherence, chemotac tic responses and phagocytosis of bovine neutrophils were evaluated, C D18 expression of neutrophils was increased after ZAS and PMA treatmen t by 12.2 and 54.2% respectively, and were significantly (p < 0.05, p < 0.01) different from those of untreated neutrophils, CD18 expression by neutrophils from a Holstein-Friesian heifer affected with leukocyt e adhesion deficiency was within negative controls when stimulated by ZAS and PMA, Adherence, chemotactic responses, and phagocytosis were s ignificantly decreased (p < 0.01) in neutrophils continuously treated with anti-CD18 MAB (MHM 23), Adherence was also significantly decrease d in anti-CD18 pretreated neutrophils. Significant (p < 9.01) differen ces of chemotactic responses and phagocytosis of neutrophils were foun d between neutrophils pretreated and continuously treated with anti-CD 18 MAB (MHM 23), Monoclonal antibodies to other surface antigens did n ot significantly alter neutrophil adherence, chemotaxis or phagocytosi s, This study demonstrated that CD18 expression on bovine neutrophils is increased significantly by stimulation with ZAS and PMA and that th e adhesion molecule CD18 plays an important role in adhesion-related f unctions.