Toxoplasma gondii antigens recognized by IgG antibodies differ between mice with and without active proliferation of tachyzoites in the brain during the chronic stage of infection

Infect Immun. 2012 Jul 30. [Epub ahead of print]

Toxoplasma gondii antigens recognized by IgG antibodies differ between mice with and without active proliferation of tachyzoites in the brain during the chronic stage of infection

Hester J, Mullins J, Sa Q, Payne L, Mercier C, Cesbron-Delauw MF, Suzuki Y.

Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky College of Medicine, 800 Rose Street, Lexington, KY 40536.

We examined whether tachyzoite proliferation in the brain of immunocompetent hosts during the chronic stage of infection with Toxoplasma gondii induces production of IgG antibodies that recognize parasite antigens different from those recognized by the antibodies of infected hosts that do not have the tachyzoite growth. For this purpose, two groups of CBA/J mice, which display continuous tachyzoite growth in their brains during the later stage of infection, were infected, and one group received treatment with sulfadiazine to prevent tachyzoite proliferation during the chronic stage of infection. T. gondii antigens recognized by the IgG antibodies from these two groups of mice were compared using immunoblotting following separation of tachyzoite antigens by two-dimensional gel electrophoresis. Several antigens, including the microneme protein MIC2, the cyst matrix protein MAG1, the dense granule proteins GRA4, and GRA7, were commonly recognized by IgG antibodies from both groups of mice. There were multiple antigens recognized mostly by IgG antibodies of only one group of mice, either with or without cerebral tachyzoite growth. The antigens recognized only by or mostly by the antibodies of mice with cerebral tachyzoite growth include MIC6, the rhoptry protein ROP1, GRA2, one heat shock protein HSP90, one (putative) heat shock protein HSP70, and the myosin heavy chain. These results indicate that IgG antibody levels increase only to selected T. gondii antigens in association with cerebral tachyzoite proliferation (reactivation of infection) in immunocompetent hosts with chronic infection.

PMID: 22851753 [PubMed - as supplied by publisher]