Attempted definition by immunoblotting of the causes of reactivity in suspected false-positive sera in the Brucella ovis complement fixation test

Authors: de Lisle GW, Joyce MA, Laybourn BJ, Reichel MP, Ross GP, Kittelberger R
Publication: New Zealand Veterinary Journal, Volume 44, Issue 5, pp 170-174, Oct 1996
Publisher: Taylor and Francis

Animal type: Livestock, Production animal, Ruminant, Sheep
Subject Terms: Bacterial, Disease/defect, Infectious disease, Clinical pathology, Diagnostic procedures, Reproduction - male, Inflammation, Notifiable organisms/exotic disease, Reproduction, Zoonosis, Public health
Article class: Scientific Article

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Abstract: Seventy-nine suspected false-positive sera, obtained over 1 year from routine submissions for Brucella ovis serological testing, were used in this study. These sera, which exhibited titres in the complement fixation test, but which because of their epidemiological history and their reactions in the enzyme-linked immunosorbent assay and gel diffusion test were suspected to be false positives, were further analysed by immunoblotting. In blots, using B. ovis antigens, rough lipopolysaccharide was identified as the major, immuno-reactive bacterial component. Antibodies against this macromolecule were present in 46.8% of the suspected falsepositive sera. In order to find out if rough lipopolysaccharides from other bacterial species could be the possible cause for the suspected false positivity, 23 sera with highest complement fixation titres were reacted in blots with cell extracts from Escherichia coli, Yersinia enterocolitica, Yersinia pseudotuberculosis, Bortedella bronchiseptica, Actinobacillus setninis, Catnpyblots with cell extracts from Escherichiu coli, Yersinia enterocolitica, Yersinia pseudotuberculosis, Bortedella bronchiseptica, Actinobacillus setninis, Catnpylobacter fetus fetus, Campylobacter jejuni, Mycobacterium paratuberculosis, Mycobacterium phlei, Corynebacterium pseudotuberculosis and pure lipopolysaccharides from Escherichia coli and Salmonella typhimurium. Despite high frequencies of antibody reaction with proteins in most of these bacterial cell extracts, which reflect the presence of infections with these bacteria, immuno-staining in the rough lipopolysaccharide region was not observed.

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