title: Characterisation of the leukotoxin produced by different strains of Pasteurella haemolytica.
abstract: Pasteurella haemolytica isolates from cattle and sheep, including representatives of different serotypes and untypable strains, were examined for leukotoxin (Lkt) production at the end of the log phase of growth in brain heart infusion broth. There were marked differences in leukotoxic activity in culture supernate samples, as measured by chemiluminescence-inhibition assays with bovine and ovine neutrophils, even between strains of the same serotype. There was also some variation in the amount and mol. wt of the Lkt protein produced by different strains, as judged by SDS-PAGE, immunoblotting and ELISA. Some strains produced normal amounts of Lkt protein which had only low leukotoxic activity. Most strains produced Lkt of 105 kDa whereas four strains produced a higher mol. wt form of c. 108 kDa, including two of the five serotype A2 strains examined. Thus, the P. haemolytica isolates showed considerable heterogeneity in terms of leukotoxin production, mol. wt and activity, even within a given serotype.
authors.affiliation: Division of Infection and Immunity, University of Glasgow.
authors.forename: M
authors.initials: M
authors.lastname: Saadati
authors.forename: H A
authors.initials: HA
authors.lastname: Gibbs
authors.forename: R
authors.initials: R
authors.lastname: Parton
authors.forename: J G
authors.initials: JG
authors.lastname: Coote
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology; D003470:Culture Media; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D005098:Exotoxins / Q000096:biosynthesis* / Q000737:chemistry / Q000633:toxicity; D015151:Immunoblotting; D008163:Luminescent Measurements; D016978:Mannheimia haemolytica / Q000145:classification / Q000378:metabolism*; D008970:Molecular Weight; D009504:Neutrophils / Q000187:drug effects; D010326:Pasteurella Infections / Q000382:microbiology / Q000662:veterinary; D012680:Sensitivity and Specificity; D012703:Serotyping; D012756:Sheep; D012757:Sheep Diseases / Q000382:microbiology
chemical_list: D003470:Culture Media; D005098:Exotoxins; C018579:leukotoxin