Cytokine and antibody responses of reactivated murine toxoplasmosis upon administration of dexamethasone
Cytokine and antibody responses of reactivated murine toxoplasmosis upon administration of dexamethasone
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DOI：
10.3347/kjp.2006.44.3.209
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发表时间：
2006-09-01
影响因子：
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通讯作者：
Lee, Young-Ha
中科院分区：
文献类型：
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作者：
Kang, Ki-Man;Choi, In-Uk;Lee, Young-Ha
刚地弓形虫已被证明在休眠寄生虫重新激活后可导致免疫功能低下患者发生危及生命的脑炎。为了获得与此现象相关的免疫应答信息，BALB/c小鼠感染了25个76K型弓形虫囊，然后口服地塞米松（弓形虫/地塞米松治疗组），以重新激活慢性弓形虫病。弓形虫感染的小鼠在实验期间没有死亡，而弓形虫/ dexa治疗的小鼠存活时间明显缩短。弓形虫/ dexa处理小鼠血清中弓形虫特异性IgG2a、IgA和IgM滴度显著降低；然而，IgG1血清滴度与弓形虫感染小鼠相似。地塞米松治疗2周后，弓形虫/地塞米松治疗小鼠CD4+和CD8 α + T细胞百分比显著降低。经Toxo/ dexa处理的小鼠体内ifn - γ和IL-10的产生水平明显下降，而IL-4的产生则暂时升高。与弓形虫感染小鼠相比，弓形虫治疗小鼠中弓形虫特异性P30和B1基因的表达水平升高。总的来说，本研究的结果表明，地塞米松治疗导致小鼠弓形虫病的再激活导致Th1免疫反应的抑制，而Th2免疫反应未受到显著影响。
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 Toxoplasma-infected 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.