title: Immune responsiveness of lambs selected for resistance to haemonchosis.
abstract: Several parameters of immune competence were measured in lambs with genetic resistance to Haemonchus contortus and in lambs with average susceptibility to H contortus (random-bred). Increase in skinfold thickness following intradermal injection was greater in resistant lambs for concanavalin A and to a lesser extent for phytohaemagglutinin. Both mitogens induced infiltration of superficial and deep dermis by eosinophils, CD4+, CD8+ and T19+ lymphocytes, though the responses did not differ between groups. Primary but not secondary antibody responses to the T cell-dependent antigen, ovalbumin was greater in resistant lambs. In contrast, antibody responses to the T cell-independent antigen, Brucella abortus lipopolysaccharide, did not differ between groups. Taken together the data suggest that enhanced T lymphocyte function may contribute to the greater resistance to H contortus of genetically resistant lambs.
authors.affiliation: Department of Animal Science, University of New England, Armidale, New South Wales, Australia.
authors.forename: H S
authors.initials: HS
authors.lastname: Gill
authors.forename: I G
authors.initials: IG
authors.lastname: Colditz
authors.forename: D L
authors.initials: DL
authors.lastname: Watson
mesh_terms: D000818:Animals; D000917:Antibody Formation; D002003:Brucella abortus / Q000276:immunology; D005838:Genotype; D006188:Haemonchiasis / Q000276:immunology / Q000662:veterinary*; D006189:Haemonchus / Q000276:immunology / Q000472:pathogenicity; D007113:Immunity, Innate / Q000235:genetics; D008070:Lipopolysaccharides / Q000276:immunology; D008213:Lymphocyte Activation; D010047:Ovalbumin / Q000276:immunology; D010270:Parasite Egg Count; D012756:Sheep / Q000276:immunology*; D012757:Sheep Diseases; D012882:Skin Tests / Q000662:veterinary; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D008070:Lipopolysaccharides; D010047:Ovalbumin