Aspects of the immune response in sheep experimentally co-infected with Corynebacterium pseudotuberculosis and Haemonchus contortus

Abstract

The present work aimed to evaluate the possible negative regulation induced by Th2 mechanisms, unleashed by the helminth Haemonchus contortus, on the response by cells of the Th1 profile, important to contain the Corynebacterium pseudotuberculosis cocobacillus infection, in the concomitant ovine infection by these two parasites. For this, the Th1 response was evaluated in two different experimental infection conditions, using the in vitro production of interferon, which is the most typical cytokine of its profile, from cultures of peripheral blood cells of ovine animals co-infected with these two parasites, compared to their production, under the same conditions, in animals only infected with the said bacterium and using as stimulus two antigen preparations with different degrees of purity. The results evidenced a tendency of reduction in the production of this cytokine in the co-infected animals in relation to those infected with Corynebacterium pseudotuberculosis alone, in the two experimental protocols. As for the response by IgG class specific antibodies against this bacterium, evaluated by ELISA and western blot, no differences were observed between groups infected only with bacillus or with double infection.