Cytokine and antibody responses of reactivated murine toxoplasmosis upon administration of dexamathasone.
Toxoplasma gondii has been shown to result in life-threatening encephalitis in immunocompromised patients after reactivation of dormant parasites. In order to obtain information on immune responses related to this phenomenon, BALB/c mice were infected with 25 cysts of the 76K strain of T. gondii, then, treated orally with dexamethasone (Toxo/Dexa-treated group) in order to reactivate the chronic toxoplasmosis. None of the T. gondii-infected mice died during the experimental periods, whereas the Toxo/Dexa-treated mice evidenced a significant attenuation of survival periods. Toxoplasma-specific IgG2a, IgA and IgM titers in sera were significantly depressed in the Toxo/Dexa-treated mice; however, the IgG1 sera titers were similar to those seen in the Toxoplasma-infected mice. The percentages of CD4+ and CD8 alpha + T cells in the Toxo/Dexa-treated mice were significantly reduced 2 weeks after dexamethasone treatment. IFN-gamma and IL-10 production levels in the Toxo/Dexa-treated mice were depressed significantly, whereas IL-4 production was increased temporarily. The expression levels of the Toxoplasma-specific P30 and B1 genes were found to have been increased in the Toxo/Dexa-treated mice in comparison with the Toxoplasmainfected mice. Collectively, the findings of this study demonstrate that reactivation of murine toxoplasmosis as the result of dexamethasone treatment induced a depression in Th1 immune responses, whereas Th2 immune responses were not significantly influenced.
Kang
Ki-Nam
KN
Department of Infection Biology, College of Medicine, Chungnam National University, Daejeon, Korea.
Choi
In-Uk
IU
Shin
Dae-Whan
DW
Lee
Young-Ha
YH
D000818:Animals; D000913:Antibodies, Protozoan / Q000096:biosynthesis* / Q000276:immunology; D016207:Cytokines / Q000096:biosynthesis*; D003907:Dexamethasone / Q000494:pharmacology*; D005260:Female; D007136:Immunoglobulins / Q000096:biosynthesis* / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D018417:Th1 Cells / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology; D014122:Toxoplasma / Q000276:immunology*; D014123:Toxoplasmosis / Q000276:immunology* / Q000469:parasitology
D000913:Antibodies, Protozoan; D016207:Cytokines; D007136:Immunoglobulins; D003907:Dexamethasone