title: The temperature-sensitive mutants of Toxoplasma gondii and ocular toxoplasmosis.
abstract: The risk of blindness caused by ocular toxoplasmosis supports efforts to improve our understanding for control of this disease. In this study, the involvement of CD8(+), CD4(+), B cell, and IL-10 gene in the immune response of primary ocular infection with the temperature-sensitive mutant (ts-4) of the RH Toxoplasma gondii strain, and in the protective immunity of ocular ts-4 vaccination and challenge with RH strain was investigated in murine models utilizing inbred C57BL/6 mice-deficient in CD4(+), CD8(+), B cells (microMT), or IL-10 gene. Compared to naive mice, all WT and mutant mice had different degree of ocular pathological changes after ts-4 ocular infection, in which both CD8 KO and IL-10 KO mice showed the most severe ocular lesions. Immunized by ts-4 intracameral (i.c.) inoculation, all mutant mice had partially decreased vaccine-induced resistance associated with increased ocular parasite burdens after RH strain challenge. A significant increase of the percentages of B cells and CD8(+) T cells in the draining lymph nodes were observed in WT and IL-10 KO mice after either infection or challenge. The levels of specific anti-toxoplasma IgG in both eye fluid and serum from all the mice were significantly increased after ts-4 i.c. immunization, except microMT mice. These results suggest that the avirulent ts-4 of T. gondii inoculated intracamerally can induce both ocular pathology and ocular protective immunity; CD4(+), CD8(+), B cell, and IL-10 gene are all necessary to the vaccine-induced resistance to ocular challenge by virulent RH strain, in which CD8(+) T cells are the most important component.
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong 510080, PR China. fanglilu@yahoo.com
authors.forename: Fangli
authors.initials: F
authors.lastname: Lu
authors.forename: Shiguang
authors.initials: S
authors.lastname: Huang
authors.forename: Lloyd H
authors.initials: LH
authors.lastname: Kasper
mesh_terms: D000818:Animals; D001402:B-Lymphocytes; D015496:CD4-Positive T-Lymphocytes; D018414:CD8-Positive T-Lymphocytes; D004195:Disease Models, Animal; D005123:Eye / Q000276:immunology / Q000469:parasitology; D005347:Fibroblasts; D006801:Humans; D016753:Interleukin-10; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout / Q000276:immunology* / Q000469:parasitology; D009154:Mutation; D016052:Protozoan Vaccines / Q000276:immunology*; D013696:Temperature; D014122:Toxoplasma / Q000235:genetics* / Q000276:immunology*; D014126:Toxoplasmosis, Ocular / Q000276:immunology / Q000469:parasitology* / Q000503:physiopathology
chemical_list: D016052:Protozoan Vaccines; D016753:Interleukin-10