Department of Immunology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.
Parasite Immunol. 2012 Jul;34(7):388-93. doi: 10.1111/j.1365-3024.2012.01369.x.
About 225 million malaria cases have been reported worldwide in 2009, and one-third of the world's population is infected with parasitic helminths. As helminths and Plasmodium are co-endemic, concurrent infections frequently occur. Helminths have been shown to modulate the host's immune response; therefore, pre-existing helminth infections may interfere with the efficient immune response to Plasmodium. To study the interaction between helminths and Plasmodium, we established a murine model of co-infection using the gastrointestinal nematode Strongyloides ratti and Plasmodium yoelii. We show that a pre-existing Strongyloides infection slightly enhanced peak parasitemia and weight loss in P. yoelii-infected BALB/c mice, while disease progression was not altered in co-infected C57BL/6 mice. The Plasmodium-induced IFN-γ production and final clearance of Plasmodium infection were not affected by S. ratti co-infection in both C57BL/6 and BALB/c mice. Interestingly, the T helper cell (Th) 2 response induced by S. ratti was significantly suppressed upon P. yoelii co-infection. This suppressed Th2 response, however, was still sufficient to allow expulsion of S. ratti parasitic adults. Taken together, we provide evidence that simultaneous presence of helminth and protist parasites does not interfere with efficient host defence in our co-infection model although changes in Th responses were observed.
2009 年全球报告约有 2.25 亿例疟疾病例，全球有三分之一的人口感染寄生虫蠕虫。由于蠕虫和疟原虫共流行，经常同时发生感染。蠕虫已被证明可调节宿主的免疫反应；因此，先前存在的蠕虫感染可能会干扰对疟原虫的有效免疫反应。为了研究蠕虫和疟原虫之间的相互作用，我们使用胃肠道线虫大鼠旋毛虫和疟原虫约氏疟原虫建立了一种同时感染的小鼠模型。我们表明，先前存在的旋毛虫感染略微增强了感染约氏疟原虫的 BALB/c 小鼠的峰值寄生虫血症和体重减轻，而在同时感染的 C57BL/6 小鼠中，疾病进展没有改变。在 C57BL/6 和 BALB/c 小鼠中，旋毛虫共感染并不影响疟原虫诱导的 IFN-γ产生和最终清除疟原虫感染。有趣的是，在约氏疟原虫共感染时，旋毛虫诱导的辅助性 T 细胞（Th）2 反应明显受到抑制。然而，这种受到抑制的 Th2 反应仍然足以允许旋毛虫寄生虫成虫的排出。总之，我们提供的证据表明，在我们的共感染模型中，尽管观察到 Th 反应的变化，但寄生虫和原生动物寄生虫的同时存在并不干扰宿主的有效防御。
