疟原虫来源的MIF同源分子与疟疾发病的分子流行病学观察及功能初探

发布时间：2018-04-02 05:26

本文选题：疟原虫　切入点：巨噬细胞迁移抑制因子　出处：《北京协和医学院》2010年博士论文

【摘要】：MIF (Macrophage Migration Inhibitory Factor)是一种具有多种生物学活性的细胞因子,在细胞生长、分化、以及天然免疫和获得免疫中都具有重要的调节作用。研究发现,宿主来源的MIF在疟疾感染病理、特别是疟疾感染导致的贫血中发挥了重要作用。近年来,包括本实验室在内的三个研究小组先后报道了三个疟原虫来源的MIF分子：Plasmodium falciparum MIF (PfMIF), P.berghei MIF (PbMIF)和P.yoelii MIF (PyMIF)。结构和功能的初步研究结果显示,疟原虫来源的MIF结构保守,与宿主MIF的活性相似,具有调节宿主巨噬细胞的活性。但是,它如何调节宿主免疫系统、以及它在疟疾感染和病理过程所扮演的角色目前仍然不清楚。本论文首先通过临床流行病学数据,系统分析了PfMIF和P.vax MIF(PvMIF)水平与疟疾感染程度和严重性之间的关系。在两种疟原虫MIF特异性检测技术建立的基础上,定量检测了疟疾病人外周血中疟原虫MIF的水平,并将其与虫血率、血红蛋白、发热情况、细胞因子等相关因素进行统计学分析。结果显示：1)患者外周血疟原虫MIF浓度与虫血率呈正相关；2)与炎症因子TNF-α、IL-10、MCP-1相关,但与TGF-β1、IL-12无关；3) PvMIF水平与人MIF (HuMIF)和发热(体温)相关,而PfMIF水平与二者无关；4)多元逐步分析结果显示虫血率、IL-10、HuMIF是PfMIF/PvMIF的预测分子。此外,本研究发现同时感染HIV、HCV和HBV并不影响患者外周血中疟原虫MIF的水平：而遗传背景(HLA基因)在一定程度上与恶性疟患者PfMIF是否检出有关。患者经抗疟药物治疗过程中,绝大部分疟疾病人外周血疟原虫MIF水平随着症状减退和虫血率的下降而下降,至治疗后三至七天完全消失。以上结果证实疟原虫MIF水平是虫血率的反映,与疟疾病情的严重程度相关,与疟疾病程及转归相关,因此理论上可以作为临床诊断疟疾病情严重程度及转归的标志分子之一。随后,本研究尝试研究P.yoelii MIF(PyMIF)对小鼠骨髓来源的树突状细胞(Bone Marrow Dendritic Cell, BM-DC)的调节效应,以宿主小鼠MIF分子作为对照,分别对BM-DC识别和捕获抗原、成熟、对T细胞效应等过程进行了分析。实验结果显示：1)尽管PyMIF显著下调BM-DC表面的TLR4水平,但并不影响BM-DC的吞噬功能；2)既不能促进未成熟BM-DC的成熟,也不能抑制LPS对BM-DC的促成熟作用；3)PyMIF通过BM-DC下调CD8+T细胞表面CD69的表达,但不影响CD8+T分泌IL-2,也不影响CD8+T细胞的细胞杀伤功能。以上结果说明尽管PyMIF对BM-DC具有某些微小的调节作用,但并不改变BM-DC的功能以及BM-DC诱导的CD8+T细胞功能。本论文工作从体内流行病学和体外细胞生物学两方面探讨了疟原虫MIF与疟疾感染和机体免疫系统之间的关系,证实疟原虫MIF与疟疾感染程度相关,并为全面认识其与机体免疫系统之间的关系提供重要数据。
[Abstract]:MIF Macrophage Migration Inhibitory Factor is a kind of cytokine with many biological activities, which plays an important role in the regulation of cell growth, differentiation, innate and acquired immunity.The study found that host-derived MIF plays an important role in the pathogenesis of malaria infection, especially anemia caused by malaria infection.In recent years, three research groups, including our laboratory, have reported three plasmodium falciparum MIF MIF molecules: Plasmodium falciparum MIF PfMIF, P.berghei MIF PbMIF) and P.yoelii MIF PyMIF.The preliminary results of structure and function showed that the structure of MIF from Plasmodium was conserved, similar to the activity of host MIF, and had the activity of regulating macrophage.But how it regulates the host immune system and its role in malaria infection and pathology remains unclear.Based on the clinical epidemiological data, the relationship between the levels of PfMIF and P.vax vMIF and the degree and severity of malaria infection was analyzed systematically in this paper.Based on the establishment of two MIF specific detection techniques, the level of Plasmodium MIF in the peripheral blood of malaria patients was quantitatively detected, and the relative factors such as blood rate, hemoglobin, fever and cytokines were analyzed statistically.The results showed that the concentration of MIF in peripheral blood of the patients was positively correlated with the blood rate of the parasite. (2) it was correlated with the inflammatory factor TNF- 伪, IL-10, MCP-1, but not with the level of TGF- 尾 1, IL-12). The level of PvMIF was correlated with MIF HuMIF) and fever (body temperature).The results of multivariate stepwise analysis showed that IL-10 HuMIF was the predictor of PfMIF/PvMIF.In addition, it was found that co-infection of HBV and HIV did not affect the level of MIF of Plasmodium falciparum in peripheral blood of patients. The genetic background of MIF gene was related to the detection of PfMIF in falciparum malaria patients to some extent.In the course of antimalarial drug treatment, the MIF level of the peripheral blood of most malaria patients decreased with the decrease of symptoms and blood rate, and disappeared completely 3 to 7 days after treatment.The above results confirm that the MIF level of Plasmodium is a reflection of the blood rate of the parasite, which is related to the severity of malaria, the course and outcome of malaria. Therefore, it can be used as a marker for clinical diagnosis of the severity and outcome of malaria.Subsequently, this study attempted to study the regulatory effects of P.yoelii MIF PyMIF on bone Marrow Dendritic cell (BM-DC) of murine bone marrow derived dendritic cells. The host mouse MIF molecule was used as a control group to recognize and capture antigens for BM-DC.The process of T cell effect was analyzed.The results showed that although PyMIF significantly down-regulated the TLR4 level on the surface of BM-DC, it did not affect the phagocytic function of BM-DC.It could not inhibit the effect of LPS on BM-DC maturation. PYMIF could down-regulate the expression of CD69 on the surface of CD8 T cells through BM-DC, but it did not affect the secretion of IL-2 by CD8 T, nor did it affect the cytotoxicity of CD8 T cells.These results suggest that although PyMIF has some minor regulatory effects on BM-DC, it does not alter the function of BM-DC and CD8 T cells induced by BM-DC.In this paper, the relationship between MIF and malaria infection and immune system in vivo and in vitro was studied. The results showed that MIF was related to the degree of malaria infection.It also provides important data for comprehensive understanding of the relationship between the immune system and the body.
【学位授予单位】：北京协和医学院
【学位级别】：博士
【学位授予年份】：2010
【分类号】：R392

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