title: A colourimetric, microplate assay for the leucotoxin of Pasteurella haemolytica.
abstract: Culture supernates of Pasteurella haemolytica, which contain leucotoxin, inhibited the reduction of nitroblue tetrazolium (NBT) by bovine and ovine but not rabbit leucocytes in response to phorbol 12-myristate 13-acetate (PMA). Culture supernates of P. multocida, which contain no leucotoxin, had no inhibitory effect on the response of leucocytes from any species. The inhibition of NBT reduction was assessed visually or spectrophotometrically in the wells of microplates and used as a simple assay for leucotoxin. It was as sensitive as the trypan blue dye-exclusion method and did not require the use of radioisotopes. In addition, sera from P. haemolytica-infected calves inhibited leucotoxin activity in the microplate assay. Thus, inhibition of NBT reduction after stimulation of ruminant leucocytes with PMA can be used as a simple, specific assay for leucotoxin and for anti-leucotoxin antibodies.
authors.affiliation: Dept. of Microbiology, University of Glasgow, Great Britain.
authors.forename: F F
authors.initials: FF
authors.lastname: Craig
authors.forename: R
authors.initials: R
authors.lastname: Dalgleish
authors.forename: A D
authors.initials: AD
authors.lastname: Sutherland
authors.forename: R
authors.initials: R
authors.lastname: Parton
authors.forename: J G
authors.initials: JG
authors.lastname: Coote
authors.forename: H A
authors.initials: HA
authors.lastname: Gibbs
authors.forename: J H
authors.initials: JH
authors.lastname: Freer
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000032:analysis*; D002417:Cattle; D002478:Cells, Cultured; D003124:Colorimetry; D003603:Cytotoxins / Q000032:analysis*; D005098:Exotoxins / Q000032:analysis*; D007962:Leukocytes / Q000187:drug effects; D009580:Nitroblue Tetrazolium; D010084:Oxidation-Reduction; D010325:Pasteurella / Q000032:analysis*; D012756:Sheep; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D001427:Bacterial Toxins; D003603:Cytotoxins; D005098:Exotoxins; C018579:leukotoxin; D009580:Nitroblue Tetrazolium; D013755:Tetradecanoylphorbol Acetate