Zhu Xiaotong, Liu Jun, Feng Yonghui, Pang Wei, Qi Zanmei, Jiang Yongjun, Shang Hong, Cao Yaming
Department of Immunology, College of Basic Medical Science, China Medical University, Shenyang, 110001, China.
Department of Laboratory Medicine, the First Hospital of China Medical University, Shenyang, Liaoning, China; The Key Laboratory of AIDS Immunology of Ministry of Health, the First Hospitol of China Medical University, Shenyang, Liaoning, China.
Exp Parasitol. 2015 Sep;156:1-11. doi: 10.1016/j.exppara.2015.05.011. Epub 2015 May 21.
Phenylhydrazine (PHZ) treatment is generally used to enhance parasitemia in infected mice models. Transient reticulocytosis is commonly observed in iron-deficient anemic hosts after treatment with iron supplementation, and is also associated with short-term hemolysis caused by PHZ treatment. In this study, we investigated the relationship between reticulocytosis and cerebral malaria (CM) in a murine model induced by PHZ administration before Plasmodium berghei ANKA (PbA) infection. Mortality and parasitemia were checked daily. Pro-inflammatory cytokines and IL-10 were quantified by ELISA. The expression of CXCL9, CXCL10, CCL5, and CXCR3 mRNAs was determined by real-time PCR. Brain sequestration of CD4(+) and CD8(+) T cells and populations of splenic Th1 CD4(+) T cells, dendritic cells (DCs), CD11b(+) Gr1(+) cells, and regulatory T cells (Tregs) were assessed by FACS. PHZ administration dramatically increased parasitemia from day 3 to day 5 post infection (p.i.) compared with the untreated control infected mice group; also, CM developed at day 5 p.i., compared with day 7 p.i. in untreated control infected mice, as well as significantly decreased blood-brain barrier function (P < 0.001). PHZ administration during PbA infection significantly increased the expression of CXCL9 (P <0.05) and VCAM-1 (P <0.001) in the brain, increased the expression of CXCL10, CCL5 and CXCR3, and significantly increased the recruitment of CD4(+) and CD8(+) T cells (P <0.001 and P <0.01, respectively) as well as CD11b(+) Gr1(+) cells to the brain. In addition, PHZ administration significantly increased the numbers of IL-12-secreting DCs at days 3 and 5 p.i. compared to those of untreated control infected mice (P <0.001 and P <0.01, respectively). Consequently, the activation of CD4(+) T cells, especially the expansion of the Th1 subset (P <0.05), was significantly and dramatically enhanced and was accompanied by marked increases in the production of protein and/or mRNA of the Th1-type pro-inflammatory mediators, IFN-γ and TNF-α (P <0.01 for both for protein; P <0.05 for TNF-α mRNA). Our results suggest that, compared to healthy individuals, people suffering from reticulocytosis may be more susceptible to severe malaria infection in malaria endemic areas. This has implications for the most appropriate selection of treatment, which may also cause reticulocytosis in patients living in such areas.
苯肼（PHZ）处理通常用于增强感染小鼠模型中的疟原虫血症。缺铁性贫血宿主在补充铁剂治疗后通常会出现短暂的网织红细胞增多，这也与PHZ处理引起的短期溶血有关。在本研究中，我们调查了在伯氏疟原虫ANKA（PbA）感染前给予PHZ诱导的小鼠模型中网织红细胞增多与脑型疟疾（CM）之间的关系。每天检查死亡率和疟原虫血症。通过酶联免疫吸附测定（ELISA）对促炎细胞因子和白细胞介素-10进行定量。通过实时聚合酶链反应（PCR）测定CXCL9、CXCL10、CCL5和CXCR3 mRNA的表达。通过荧光激活细胞分选（FACS）评估CD4(+)和CD8(+) T细胞在脑内的滞留以及脾Th1 CD4(+) T细胞、树突状细胞（DC）、CD11b(+) Gr1(+)细胞和调节性T细胞（Treg）的数量。与未处理的对照感染小鼠组相比，感染后第3天至第5天给予PHZ显著增加了疟原虫血症；此外，与未处理的对照感染小鼠在感染后第7天相比，给予PHZ的小鼠在感染后第5天出现了CM，并且血脑屏障功能显著降低（P < 0.001）。在PbA感染期间给予PHZ显著增加了脑中CXCL9（P <0.05）和血管细胞黏附分子-1（VCAM-1，P <0.001）的表达，增加了CXCL10、CCL5和CXCR3的表达，并显著增加了CD4(+)和CD8(+) T细胞（分别为P <0.001和P <0.01）以及CD11b(+) Gr1(+)细胞向脑内的募集。此外，与未处理的对照感染小鼠相比，在感染后第3天和第5天给予PHZ显著增加了分泌白细胞介素-12的DC的数量（分别为P <0.001和P <0.01）。因此，CD4(+) T细胞的活化，尤其是Th1亚群的扩增（P <0.05）显著且明显增强，并伴随着Th1型促炎介质干扰素-γ和肿瘤坏死因子-α的蛋白质和/或mRNA产生的显著增加（蛋白质两者均为P <0.01；肿瘤坏死因子-α mRNA为P <0.05）。我们的结果表明，与健康个体相比，患有网织红细胞增多症的人在疟疾流行地区可能更容易感染严重的疟疾。这对于最恰当的治疗选择具有启示意义，而这种治疗也可能导致生活在这些地区的患者出现网织红细胞增多。
