灭活肺炎链球菌对人单核细胞MMP-12表达的上调作用

发布时间：2018-07-27 21:24

【摘要】： 肺炎链球菌寄生于人的鼻咽部,是人类主要的致病菌之一,可导致肺炎、菌血症、中耳炎及脑膜炎等多种疾病,至今在儿童中仍有很高的死亡率,每年5岁以下儿童死亡病例中有10%是由肺炎链球菌感染所致。近年来,肺炎链球菌耐药菌株的不断增加,使得对肺炎链球菌感染的治疗越来越困难,人体自身免疫系统在抵抗感染中的作用又逐渐地受到重视。感染肺炎链球菌后,机体多种免疫机制参与清除致病菌的反应,其中肺巨噬细胞作用独特,它不仅直接吞噬细菌、分泌细胞因子、产生抗体,还可以清除其他坏死的炎症细胞,比如坏死的中性粒细胞等。动物实验表明,当巨噬细胞缺失时,感染肺炎链球菌后,炎症反应更加剧烈,死亡率也更高。肺巨噬细胞由外周血中的单核细胞进入肺组织后分化而来。肺炎链球菌感染可以缩短骨髓中未成熟单核细胞进入循环系统的时间,肺炎链球菌感染后,外周血中单核细胞的数目增加;此外,研究表明,肺炎链球菌感染后,肺组织中的巨噬细胞数目也增加,可见肺炎链球菌感染可以引起外周血单核细胞向肺组织中的募集。在从循环系统迁移到肺组织的过程中,外周血单核细胞需要穿过血管基底膜、肺组织,而血管基底膜及肺组织中含有大量的细胞外基质(extracellular matrix, ECM),比如胶原、弹性蛋白等,基质金属蛋白酶(Matrix metalloproteinases, MMPs)在单核细胞的迁移过程中发挥了重要的作用。
[Abstract]:Streptococcus pneumoniae, parasitic on human nasopharynx, is one of the main pathogenic bacteria of human beings. It can cause pneumonia, bacteremia, otitis media, meningitis and other diseases. So far, it still has a high mortality rate among children. Ten per cent of deaths in children under 5 years of age are caused by Streptococcus pneumoniae infection. In recent years, with the increasing of drug-resistant strains of Streptococcus pneumoniae, the treatment of Streptococcus pneumoniae infection becomes more and more difficult, and the role of human autoimmune system in the resistance to infection has been gradually paid attention to. After infection with Streptococcus pneumoniae, various immune mechanisms are involved in the clearance of pathogenic bacteria. Pulmonary macrophages play a unique role in not only phagocytosis of bacteria, secretion of cytokines, production of antibodies, but also removal of other necrotic inflammatory cells. Such as necrotic neutrophil and so on. Animal experiments have shown that when macrophages are absent, the inflammatory response is more intense and mortality is higher after infection with Streptococcus pneumoniae. Pulmonary macrophages differentiate from monocytes from peripheral blood into lung tissue. Streptococcus pneumoniae infection shortens the time for immature monocytes in bone marrow to enter the circulatory system. The number of monocytes in peripheral blood increases after Streptococcus pneumoniae infection. The number of macrophages in lung tissue also increased, suggesting that Streptococcus pneumoniae infection can cause the recruitment of peripheral blood monocytes into lung tissue. In the process of migration from circulatory system to lung tissue, peripheral blood mononuclear cells need to pass through vascular basement membrane, lung tissue, and vascular basement membrane and lung tissue contain a large amount of extracellular matrix (extracellular matrix, ECM), such as collagen, elastin, etc. Matrix metalloproteinases (Matrix metalloproteinases, MMPs) play an important role in the migration of monocytes.
【学位授予单位】：大连医科大学
【学位级别】：硕士
【学位授予年份】：2006
【分类号】：R392

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