英国普林斯顿代写作业 免疫系统

2020-04-17 07:08

人体对病原体的防御是免疫系统。该系统由两个固有防御系统组成，即固有防御系统(非特异性防御)和适应性防御系统(特异性防御)。在先天系统中，皮肤和粘膜是第一道防线，而自然杀伤(NK)细胞、吞噬细胞、抗菌蛋白、炎症和发烧则是第二道防线。适应性防御系统是人体抵御病原体的第三道防线。它包括体液反应(涉及B细胞)和细胞反应(涉及T细胞)。先天防御系统和适应性防御系统既相互独立又相互协作，以保护身体免受外来入侵。免疫细胞之间的交流是通过细胞因子进行的。细胞因子是一种小蛋白，由许多不同的细胞产生，参与细胞间的通讯。Interleukin-1β(IL-1β)和白细胞介素- 6都是促炎细胞因子产生的单核细胞,NK淋巴细胞,T淋巴细胞和巨噬细胞感染。IL-1β参与细胞分化、细胞增殖和组织修复,而il - 6刺激生产的急性期蛋白质在回应一个受伤。这些促炎细胞因子水平升高与包括癌症在内的许多疾病状态有关。因此，在没有感染或损伤的情况下，这些炎症调节因子的合成和分泌可能导致慢性炎症和导致的疾病，如肿瘤生长、类风湿关节炎、克罗恩病和多发性硬化症。既往研究表明，HBCD通过降低NK细胞的结合功能和细胞表面标志物的表达来降低NK细胞杀伤肿瘤细胞的能力(Hinkson and Whalen 2009, 2010)。这种对NK细胞功能的修饰会降低NK细胞的裂解能力。从这些结果可以看出，HBCD有可能破坏正常的免疫细胞功能，从而导致各种疾病和肿瘤的生长。
英国普林斯顿代写作业 免疫系统
The human body’s defense against pathogens is the immune system. This system consists of two inherent defense systems, the innate (nonspecific) system and the adaptive (specific) system. Within the innate system the skin and mucous membranes is the first line of defense, while natural killer (NK) cells, phagocytes, antimicrobial proteins, inflammation and fever acts as the second line of defense. The adaptive defense system is the body’s third line of defense against pathogens. It consists of the humoral response (involving B cells) and the cellular response (involving T cells).  The innate and adaptive defense systems work both independently and cooperatively with each other in order to protect the body against foreign invaders. Communication between the immune cells occurs via cytokines. Cytokines are small proteins that are produced by a number of different cell and are involved in cell-to-cell communication. Interleukin-1β (IL-1β) and interleukin-6 are both pro-inflammatory cytokines produced by monocytes, NK lymphocytes, T lymphocytes and macrophages in response to an infection. IL-1β is involved with cell differentiation, cell proliferation and tissue repair, while IL-6 stimulates the production of acute phase proteins in response to an injury. Elevated levels of these pro-inflammatory cytokines have been associated with numerous disease states including cancer. Thus, synthesis and secretion of these regulators of inflammation in the absence of infection or injury can lead to chronic inflammation and those diseases that results, such as tumor growth, rheumatoid arthritis, Crohn’s disease, and multiple sclerosis.Previous studies have shown that HBCD decreases the ability of NK cells to destroy tumor cells by decreasing the binding function and cell-surface marker expression in NK cells (Hinkson and Whalen 2009, 2010). This modification of the NK cell’s function can in turn decrease the lytic capability of the NK cells. From these results it can be observed that HBCD has the capability to potentially disrupt normal immune cellular functions which can lead to various diseases and tumor growth. 

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