title: Anti-haemolysin IgG1 to IgG2 ratios correlate with haemolysin neutralization titres and lung lesion scores in Actinobacillus pleuropneumoniae infected pigs.
abstract: Currently available porcine Actinobacillus pleuropneumoniae bacterins afford only minimal protection by decreasing mortality but not morbidity. To evaluate a possible role of IgG subclasses in protection, IgG1 and IgG2 responses to A. pleuropneumoniae haemolysin (HLY) were examined in piglets exposed to a low dose (10(5) c.f.u. ml-1) of A. pleuropneumoniae CM5 (LD) given by aerosol (which affords complete protection) or bacterin-vaccinated piglets (no protection). Only the LD group developed HLY neutralizing antibody. These animals produced both IgG1 and IgG2-associated antibody in response to HLY, and there was a positive correlation (r = 0.6) between IgG1 anti-HLY antibody and neutralizing titres. Anti-HLY IgG1 antibody was negatively correlated with pneumonic scores at necropsy (r = -0.67, p < or = 0.005). These results suggest that immunization procedures that bias anti-HLY antibody to IgG1 may be more efficacious than those inducing IgG2.
authors.affiliation: Department of Pathobiology, Ontario Veterinary College, University of Guelph, Canada.
authors.forename: S E
authors.initials: SE
authors.lastname: Furesz
authors.forename: B N
authors.initials: BN
authors.lastname: Wilkie
authors.forename: B A
authors.initials: BA
authors.lastname: Mallard
authors.forename: S
authors.initials: S
authors.lastname: Rosendal
authors.forename: J I
authors.initials: JI
authors.lastname: MacInnes
mesh_terms: D000189:Actinobacillus Infections / Q000276:immunology* / Q000473:pathology* / Q000517:prevention & control; D016977:Actinobacillus pleuropneumoniae; D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis; D001428:Bacterial Vaccines / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D006460:Hemolysin Proteins / Q000276:immunology*; D007117:Immunization, Secondary / Q000662:veterinary; D007074:Immunoglobulin G / Q000096:biosynthesis / Q000276:immunology*; D008168:Lung / Q000473:pathology*; D009500:Neutralization Tests / Q000662:veterinary; D013552:Swine; D013553:Swine Diseases / Q000276:immunology* / Q000473:pathology* / Q000517:prevention & control
chemical_list: D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; D006460:Hemolysin Proteins; D007074:Immunoglobulin G