TY - JOUR T1 - Parasite distribution and associated immune response during the acute phase of Toxoplasma gondii infection in sheep. JF - BMC Vet Res Y1 - 2014 A1 - Verhelst, Delfien A1 - Stéphane De Craeye A1 - Entrican, Gary A1 - Dorny, Pierre A1 - Cox, Eric KW - Acute-Phase Reaction KW - Animals KW - Antibodies, Protozoan KW - Antigens, Protozoan KW - Cytokines KW - Enterocytes KW - Enzyme-Linked Immunosorbent Assay KW - Fluorescent Antibody Technique, Indirect KW - Intestines KW - Lymph Nodes KW - Real-Time Polymerase Chain Reaction KW - Sheep KW - Sheep Diseases KW - Spleen KW - Toxoplasma KW - Toxoplasmosis, Animal AB -

BACKGROUND: In many countries, Toxoplasma gondii (T. gondii) is a major cause of reproductive disorders and abortions in the sheep industry, and therefore responsible for important financial and economic losses. In addition, undercooked infected lamb is an important risk factor for human toxoplasmosis. In the present study, the initial phase of the infection was investigated: the parasite's entry site, the subsequent distribution of the parasite and the host-immune response.

RESULTS: Parasite DNA was already detected in the cranial small intestinal mucosa the first days after oral infection with T. gondii tissue cysts. Simultaneously, high IFN-gamma and IL-12 responses were induced mainly in the mesenteric lymph nodes. The emergence of IgG1 (at 8dpi), and IgG2 (at 11 dpi) was accompanied by a decrease or even disappearance of the IFN-gamma and IL-12 response in the Peyers' patches (PP), PBMC's and popliteal LN's. Meanwhile the parasite DNA could be recovered from most mucosal and systemic tissues to become undetectable in the small intestine, popliteal LN, PBMC and spleen 3 weeks pi.

CONCLUSIONS: Our results indicate that parasites enter the cranial small intestine the first days after infection and that after an increase the first two weeks after infection, the parasite DNA levels in the intestine drop below the detection limit three weeks after infection. This coincides with an increase in parastic-specific serum IgG1 and IgG2 and a decrease of the antigen-specific IFN-gamma response in PP, PBMC and popliteal LN. We suggest a role for IFN-gamma and IL-12 in controlling the infection.

VL - 10 U1 - http://www.ncbi.nlm.nih.gov/pubmed/25511864?dopt=Abstract M3 - 10.1186/s12917-014-0293-5 ER -