Free Access
Vet. Res.
Volume 37, Number 4, July-August 2006
Page(s) 607 - 622
Published online 16 May 2006
How to cite this article Vet. Res. (2006) 607-622
Vet. Res. 37 (2006) 607-622
DOI: 10.1051/vetres:2006022

Haemonchus contortus (Nematoda: Trichostrongylidae) infection in lambs elicits an unequivocal Th2 immune response

Caroline Lacrouxa, Thi Hai Chi Nguyenb, Olivier Andreolettia, Françoise Prevota, Christelle Griseza, Jean-Paul Bergeauda, Lucas Grunerc, Jean-Claude Bruneld, Dominique Francoise, Philippe Dorchiesa and Philippe Jacquieta

a  UMR INRA-ENVT 1225 Interactions Hôtes Agents Pathogènes, École Nationale Vétérinaire de Toulouse, 23 chemin des Capelles, 31076 Toulouse Cedex 03, France
b  Université d'Agriculture et de Foresterie de Ho Chi Minh Ville, Vietnam
c  INRA, Écologie et Génétique des Parasites, BioAgresseurs Santé et Environnement, 37880 Nouzilly, France
d  INRA, Domaine Expérimental de la Sapinière, 18390 Osmoy, France
e  INRA, Station d'Amélioration Génétique des Animaux, BP 27, 31326 Castanet-Tolosan, France

(Received 28 October 2005; accepted 7 February 2006; published online 16 May 2006)

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.

Key words: Haemonchus contortus / sheep / Th2 immune response / quantitative PCR / antibody and cellular response

Corresponding author: Philippe Jacquiet

© INRA, EDP Sciences 2006