Molecular and cellular analysis of the host immune reactions to infection with Neospora caninum (Apicomplexa)

• Unité de recherche: COST
• Numéro de projet: C96.0068
• Titre du projet anglais: Molecular and cellular analysis of the host immune reactions to infection with Neospora caninum (Apicomplexa)

Mots-clé (Anglais)

Neospora caninum; stillbirth in cattle; intracellular parasite; tachyzoites; bradyzoites

Programme de recherche (Anglais)

COST-Action 820 - Vaccins contre les coccidioses animales

Description succincte (Anglais)

See abstract

Partenaires et organisations internationales (Anglais)

B, CH, CZ, D, DK, E, F, H, I, IRL, N, NL, PL, S, UK

Résumé des résultats (Abstract) (Anglais)

Neospora caninum has now been recognized as one of the most important causes of abortion or stillbirth in cattle of Switzerland (and other industrialised countries). N. caninum is an obligatory intracellular parasite, with two stages, namely tachyzoites and bradyzoites, in the intermediate host such as cattle. The life cycle of N. caninum can include dogs as definitive host, this very new finding has been reported a few months ago. Our aim in immunological research is to characterize the host immune reactions following Neospora caninum infection: In continuation of our previous work, we have further assessed experimental infection on wild type mice and antibody-knockout mice in view of immuno-pathological events being putatively responsible for the course of infection, respectively death or recovery of the host. Our research has been highlighted by two findings: First, splenocyte proliferation was shown to be actively suppressed by live N. caninum infection during early phase of infection. Secondly, we could show that N. caninum increases both expression of iNOS and production of NO in cells of brain and spleen. The lethal outcome of B-cell deficient mice thus may be partially explained by an overproduction of NO. In a new phase of the project, we have started the first trials of inducing putatively protective immune responses by acUve or passive immunization. This was achieved either by passive transfer of monoclonal antibodies (anti-Neospora-ISCOM-antibodies, directed against (predominantly) surface membrane proteins of Neospora tachyzoites), or by active immunization using native or recombinant proteins of parasite tachyzoites. Protective immunity has preliminarily been induced by immunization with Neospora-SA-antigen and with recombinant Nc-p43-antigen.

Références bases de données (Anglais)

Swiss Database: COST-DB of the State Secretariat for Education and Research Hallwylstrasse 4 CH-3003 Berne, Switzerland Tel. [phone] Swiss Project-Number: C96.0068