Submitted to: BARC Poster Day
Publication Type: Proceedings
Publication Acceptance Date: 2/15/1998
Publication Date: N/A
Technical Abstract: Toxoplasmosis occurs in a variety of livestock and in humans, causing abortions, mental retardation in newborns, and encephalitis in immunocompromised individuals. Among food animals pigs are considered the major source of human Toxoplasma gondii infection in the US. How swine become infected in nature is not fully known, but it is clear that T. gondii oocysts shed in cat feces play an important role as direct contaminants of pig feed and water. Recent field surveys, however, have shown a continuing prevalence of this foodborne disease. The major strategy for prevention of toxoplasmosis in swine is the identification of factors and of vaccines, or specific T. gondii antigens, which induce protective responses. Serologic titers have been reported for swine but these are highly variable and, as with other species, not predictive of effective immunity. The specific objective was to define the protective response to T. gondii. A group of 24 piglets of different SLA haplotypes were tested for a period of 6 weeks after natural infection with T. gondii oocysts. Cell subsets from peripheral blood were tested using a broad panel of monoclonal antibodies that identify important swine B and T cell subsets. Due to the important role of the immune cytokine, interferon-g, in the prevention of human and murine T. gondii infection, we tested the ability of swine peripheral blood lymphocytes to produce this cytokine using the cytokine specific capture ELISA. Parasite burden was assessed in tongue and brain tissues from all pigs after necropsy by bioassay in mice and cats to determine whether genetically resistant pigs could be identified. These studies should provide valuable information on controlling toxoplasmosis in pigs.