RESUMEN
An experimental mouse model to analyze the interaction between the immune responses elicited following infection with Nippostrongylus brasiliensis and Chlamydophila abortus has been established. Mice infected with C. abortus 7 days after N. brasiliensis showed an increased bacterial multiplication in spleen and liver compared to bacteria-alone infected mice. However the morbidity of these mice, expressed as weight loss, was significantly lower. Analysis of the immune responses elicited showed that spleen from co-infected mice had reduced IFN-gamma production in response to C. abortus antigen. The bias towards a type 2 response in co-infected mice was confirmed by an increase in the production of IL-4 and in the lower ratio IgG2a/IgG1. In pregnant mice co-infection caused a delay in the time of abortion and an increased systemic susceptibility to C. abortus infection.