title: Importance of CD8(+)Vbeta8(+) T cells in IFN-gamma-mediated prevention of toxoplasmic encephalitis in genetically resistant BALB/c mice.
abstract: In our attempt to identify a major T cell population(s) that recognizes protective Toxoplasma gondii antigens and produces interferon-gamma (IFN-gamma) for prevention of toxoplasmic encephalitis (TE), we found T cell receptor Vbeta8(+) cells to be the most frequent IFN-gamma-producing population infiltrated into the brain of T. gondii-infected BALB/c mice genetically resistant to the disease. To examine the role of IFN-gamma production by this T cell population for resistance, we transferred Vbeta8(+) immune T cells purified from spleens of infected BALB/c and IFN-gamma(/) mice into infected, sulfadiazine-treated, athymic nude mice. After discontinuation of sulfadiazine treatment, control nude mice that had not received any T cells and animals that had received Vbeta8(+) T cells from IFN-gamma(/) mice all died because of reactivation of infection (TE). In contrast, animals that had received the cells from BALB/c mice survived. Thus, IFN-gamma production by Vbeta8(+) T cells plays an important role in prevention of TE in these animals. When Vbeta8(+) immune T cells were divided into CD4(+) and CD8(+) subsets, a potent protective activity was observed only in the CD8(+) subset, whereas a combination of both subsets provided greater protection than did the CD8(+)Vbeta8(+) population alone. These results indicate that the CD8(+) subset of Vbeta8(+) T cells is a major afferent limb of IFN-gamma-mediated resistance of BALB/c mice against TE, although the CD4(+) subset of the T cell population works additively or synergistically with the CD8(+)Vbeta8(+) population.
authors.affiliation: Center for Molecular Medicine and Infectious Diseases, Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
authors.forename: Xisheng
authors.initials: X
authors.lastname: Wang
authors.forename: Jennifer
authors.initials: J
authors.lastname: Claflin
authors.forename: Hoil
authors.initials: H
authors.lastname: Kang
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Suzuki
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D004660:Encephalitis / Q000276:immunology* / Q000469:parasitology; D005260:Female; D007371:Interferon-gamma / Q000172:deficiency / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000276:immunology; D014122:Toxoplasma / Q000276:immunology; D014124:Toxoplasmosis, Animal / Q000276:immunology*; D016781:Toxoplasmosis, Cerebral / Q000276:immunology*
chemical_list: D000953:Antigens, Protozoan; D016693:Receptors, Antigen, T-Cell, alpha-beta; D007371:Interferon-gamma