title: Haemonchus contortus (Nematoda: Trichostrongylidae) infection in lambs elicits an unequivocal Th2 immune response.
abstract: Selection of resistant animals and host immunization have been proposed as alternative methods for the control of gastrointestinal nematode parasites. However, a better knowledge of the mechanisms involved in protective immunity against these parasites is required for the development of optimal strategies. In this study, 3 month old INRA 401 lambs (n = 81) were allocated into three groups: uninfected control, challenged either once (primary-infected animals) or twice (previously-infected animals) with 10,000 Haemonchus contortus L3. Uninfected control and challenged animals were sequentially sacrificed at 3, 7, 15 and 28 days post challenge. In both challenged groups, a clear Th2-oriented immune response was observed in the abomasal lymph node and mucosa. IL-4 and IL-13 mRNA over-expression, recruitment of eosinophils, mast cells and globule leukocytes and production of specific systemic IgG and mucosal IgA were observed earlier in previously-infected animals than in primary-infected ones. At 28 days post infection, no differences between intensities of these responses were observed between the challenged groups. Worm establishment rates were similar in previously-infected and primary-infected lambs. However, reductions of worm development, female fecundity and fecal egg output were observed in previously-infected sheep. We conclude that H. contortus infection in young INRA 401 lambs induced an unequivocal Th2 immune response resulting in the regulation of worm egg production without affecting their establishment.
authors.affiliation: UMR INRA-ENVT 1225 Interactions Hôtes Agents Pathogènes, Ecole Nationale Vétérinaire de Toulouse, 23 chemin des Capelles, 31076 Toulouse Cedex 03, France.
authors.forename: Caroline
authors.initials: C
authors.lastname: Lacroux
authors.forename: Thi Hai Chi
authors.initials: TH
authors.lastname: Nguyen
authors.forename: Olivier
authors.initials: O
authors.lastname: Andreoletti
authors.forename: Françoise
authors.initials: F
authors.lastname: Prevot
authors.forename: Christelle
authors.initials: C
authors.lastname: Grisez
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Bergeaud
authors.forename: Lucas
authors.initials: L
authors.lastname: Gruner
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Brunel
authors.forename: Dominique
authors.initials: D
authors.lastname: Francois
authors.forename: Philippe
authors.initials: P
authors.lastname: Dorchies
authors.forename: Philippe
authors.initials: P
authors.lastname: Jacquiet
mesh_terms: D000018:Abomasum; D000818:Animals; D000947:Antigens, Helminth; D005260:Female; D005748:Gastric Fundus / Q000378:metabolism; D005753:Gastric Mucosa / Q000378:metabolism; D005786:Gene Expression Regulation; D006188:Haemonchiasis / Q000276:immunology / Q000662:veterinary*; D007814:Larva / Q000254:growth & development; D008198:Lymph Nodes / Q000378:metabolism; D009348:Nematoda / Q000276:immunology*; D012333:RNA, Messenger / Q000378:metabolism; D012756:Sheep; D012757:Sheep Diseases / Q000276:immunology* / Q000469:parasitology; D018418:Th2 Cells / Q000276:immunology*
chemical_list: D000947:Antigens, Helminth; D012333:RNA, Messenger