Bovine CD18 identified as a species specific receptor for Pasteurella haemolytica leukotoxin

Ligand blotting of Pasteurella haemolytica leukotoxin (LKT) susceptible BL3 bovine lymphoma cell membranes with LKT detected two putative receptors wi th M-r, of 95 and 100 kDa, whereas no LKT binding to membrane proteins was detected for LKT non-susceptible human leukemic cells. Anti-bovine CD18 and CD11a/CD18 mAb recognized 95 and 100kDa bands from BL3 cell membranes. CD1 8 isolated from BL3 cell membranes bound LKT. Pre-incubation of BL3 cells w ith anti-bovine CD18 or CD11a/CD18 mAb caused partial inhibition of LKT-ind uced leukolysis. Therefore, we propose that bovine CD18 acts as a species-s pecific leukocyte receptor for P. haemolytica LKT. (C) 1999 Elsevier Scienc e B.V. All rights reserved.