title: Serological studies of Actinobacillus (Haemophilus) pleuropneumoniae strains of serotype 6 and their antigenic relationship with other serotypes.
abstract: Serological tests such as agglutination, coagglutination, precipitation and indirect haemagglutination were used to study the antigenic relationship of reference and field strains of Actinobacillus (Haemophilus) pleuropneumoniae of serotype 6 with reference strains of other serotypes. Both cell-associated particulate and cell-free soluble antigens prepared from unheated and heat-treated bacterial suspensions of reference and field strains of serotype 6 were used in the studies. Species-specific, common antigenic determinants associated mainly with heat-treated particulate antigens of serotype 6 were cross-reactive in tube agglutination tests with almost all the serotypes. The species-specific antigens were of a minor nature because the cross-reactivities were abolished in both 2-mercaptoethanol agglutination and coagglutination tests. Cell-free saline extracts of both unheated and heat-treated suspensions of serotype 6 strains possessed epitopes specific for serotypes 3, 5 and 8 in addition to their own specific determinants. The epitopes were dominant because the reactions of strains of serotype 6 with antisera against serotypes 3, 5 and 8 persisted in almost all the serological tests used. Serotype 6 strains were antigenically closer to serotype 8 than to serotypes 3 or 5. A combination of serological tests such as coagglutination followed by 2-mercaptoethanol tube agglutination and, or, immunodiffusion tests differentiated serotype 6 strains from those of other cross-reacting serotypes.
authors: Groupe de Recherche sur les Maladies Infectieuses du Porc, Faculté de Médecine Vétérinaire, Université de Montréal. Saint-Hyacinthe, Quebec, Canada.
authors: K R
authors: KR
authors: Mittal
authors: R
authors: R
authors: Higgins
authors: S
authors: S
authors: Larivière
mesh_terms: D000188:Actinobacillus / Q000145:classification / Q000276:immunology*; D000942:Antigens, Bacterial / Q000032:analysis*; D012699:Serology; D012703:Serotyping
chemical_list: D000942:Antigens, Bacterial