Mannheimia haemolytica leukotoxin-induced cytolysis of caprine (Capra hircus) leukocytes is mediated by the CD18 subunit of beta2-integrins.
Mannheimiosis is the major respiratory disease among some ruminants, whereas it is not pathogenic for other mammals, an observation that has been attributed to a specific interaction between Mannheimia haemolytica leukotoxin (Lkt) and bovine or ovine CD18 subunit of lymphocyte function-associated antigen-1 (LFA-1) and Mac-1. We therefore hypothesized that Lkt utilizes CD18 as its receptor on caprine leukocytes as well. We have transiently transfected the beta2-integrins-deficient K-562 cell line with cDNAs encoding caprine CD11a and caprine CD18 to determine the susceptibility of the transfectants to Lkt-induced cytolysis. Flow cytometric analysis of the transfectants revealed surface expression of caprine LFA-1 and lysis by Lkt in a concentration-dependent manner whereas the parent cells were not. Moreover, K562 cells expressing caprine CD18 and human or bovine CD11a were also sensitive to Lkt whereas K-562 cells expressing caprine CD11a and human CD18 were not. Taken together, these results indicate that CD18 on caprine leukocytes serves as a receptor for Lkt.
Fett
T
T
Department of Pathology, Faculty of Veterinary Medicine, University of Liege, FMV Sart Tilman B43, B-4000 Liege, Belgium.
Zecchinon
L
L
Vanden Bergh
P
P
Desmecht
D
D
D000818:Animals; D001427:Bacterial Toxins / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification; D018845:CD11 Antigens / Q000235:genetics / Q000276:immunology; D018821:CD18 Antigens / Q000235:genetics / Q000276:immunology*; D002417:Cattle; D002460:Cell Line; D003603:Cytotoxins / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D005098:Exotoxins / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D015511:Goat Diseases / Q000276:immunology / Q000382:microbiology; D006041:Goats; D006801:Humans; D007962:Leukocytes / Q000276:immunology*; D016169:Lymphocyte Function-Associated Antigen-1 / Q000235:genetics / Q000276:immunology; D016978:Mannheimia haemolytica / Q000235:genetics / Q000276:immunology* / Q000472:pathogenicity; D016871:Pasteurellaceae Infections / Q000276:immunology / Q000382:microbiology / Q000662:veterinary; D011485:Protein Binding
D001427:Bacterial Toxins; D018845:CD11 Antigens; D018821:CD18 Antigens; D003603:Cytotoxins; D005098:Exotoxins; D016169:Lymphocyte Function-Associated Antigen-1; C018579:leukotoxin