Modulation of immunity in mice with latent toxoplasmosis-the experimental support for the immunosuppression hypothesis

Parasitol Res. 2010 Aug 19. [Epub ahead of print]

Modulation of immunity in mice with latent toxoplasmosis-the experimental support for the immunosuppression hypothesis of Toxoplasma-induced changes in reproduction of mice and humans

Kaňková S, Holáň V, Zajícová A, Kodym P, Flegr J.

Department of Philosophy and History of Science, Faculty of Science, Charles University in Prague, Vinicná 7, 128 44, Prague 2, Czech Republic.

Abstract
The immunosuppression hypothesis suggests that the increased sex ratio in mice and women with latent toxoplasmosis, retarded embryonic growth in the early phases of pregnancy, prolonged pregnancy of Toxoplasma-infected women, and increased prevalence of toxoplasmosis in mothers of children with Down syndrome can be explained by the presumed immunosuppressive effects of latent toxoplasmosis. Here, we searched for indices of immunosuppression in mice experimentally infected with Toxoplasma gondii. Our results showed that mice in the early phase of latent infection exhibited temporarily increased production of interleukin (IL)-12 and decreased production of IL-10. In accordance with the immunosuppression hypothesis, the mice showed decreased production of IL-2 and nitric oxide and decreased proliferation reaction (synthesis of DNA) in the mixed lymphocyte culture in the early and also in the late phases of latent toxoplasmosis. Since about 30% of the world population are latently infected by T. gondii, the toxoplasmosis-associated immunosuppression might have serious public health consequences.

PMID: 20721578 [PubMed - as supplied by publisher]