Serologic studies of Actinobacillus (Haemophilus) pleuropneumoniae strains of serotype-3 and their antigenic relationships with other A pleuropneumoniae serotypes in swine
Mittal, K.R.; Higgins, R.; Larivière, S.
American Journal of Veterinary Research 49(2): 152-155
1988
ISSN/ISBN: 0002-9645 PMID: 2450495 Document Number: 319645
Serotype-3 strains of Actinobacillus pleuropneumoniae possess epitopes shared with almost all other Actinobacillus serotypes. Common epitopes detected in particulate antigens were heat-labile and heat-stable and were of minor nature. Additional cross-reactive epitopes were detected in soluble and particulate antigens prepared from strains of serotypes 3, 6 and 8. Crossreactions occurring between serotype-3 antigens and those of other serotypes were of 2 types: one associated mainly with 2-mercaptoethanol (2-ME)-sensitive IgM antibodies and the other associated mainly with 2-ME-resistant IgG antibodies. The cross-reactivity between serotypes 3, 6 and 8 was associated mainly with IgG antibodies, as shown by the results of 2-ME tube agglutination, 2-ME-indirect haemagglutination and coagglutination tests. None of the tests was entirely satisfactory for serotyping serotype-3 isolates, mainly as a result of overlapping of type-specific antigenic determinants of serotypes 3, 6 and 8 in different combinations in the same strain. A combination of tests, using particulate and soluble antigens, may be necessary for typing of serotype-3 isolates.