Antibodies Immunoglobulins Activation of complement system The antibody coated

Antibodies (Immunoglobulins) ◦ Activation of complement system : The antibody-coated antigen is subject to a chemical chain reaction with complement, which is a series of proteins found in the blood ◦ 补体系统的激活：抗体包被的抗原与补体发生化学链反应，补体是血液中发现的一系列蛋白质 ◦ The complement reaction either can trigger the lysis (bursting) of the invading microbe or can attract microbe-killing scavenger cells that ingest, or phagocytose, the invader ◦ 补体反应可以触发入侵微生物的裂解（爆发），或者可以吸引吞噬入侵者或吞噬入侵者的杀死微生物的清除剂细胞。 ◦ Opsonization : phagocytic cell recognizes the antibody and binds to it which helps it to then engulf and destroy the pathogen ◦ 调理作用：吞噬细胞识别抗体并与其结合，从而帮助其吞噬并消灭病原体

Antibodies (Immunoglobulins)  Antibody production continues for several days until all antigen molecules are removed.  抗体生产持续数天，直到所有抗原分子被清除。  Antibodies remain in circulation for several months, providing extended immunity against that particular antigen.  抗体可以循环流通几个月，从而提供针对该特定抗原的扩展免疫力。

Altering immune function ◦ Altered immunity can result from: 免疫力改变可能是由于 1. Failure of the host defense mechanisms (break in the skin, inhalation of pathogen extra) 2. 宿主防御机制失灵（皮肤破裂，病原体额外吸入） 3. Hypersensitivity – inappropriate, excessive response immune response 4. – 过敏症不适当的过度反应免疫反应 5. Autoimmunity – inappropriate response to self (an autoimmune disease, rheumatoid arthritis) 6. – 自身免疫对自身的不适当反应（自身免疫疾病，类风湿关节炎） 7. Alloimmunity – reaction directed at tissue antigens from other individuals of the same species 8. – 同种免疫针对来自同一物种其他个体的组织抗原的反应

Host defense failure  Pathogen try to evade detection by the immune system by having multi-variations of antigens  病原体试图通过具有多种抗原变异来逃避免疫系统的检测  Making it difficult for the T and B lymphocytes to recognize the pathogen  T 和 B 淋巴细胞难以识别病原体  Antigenic variation: 抗原变异：  Pathogen contains A, B, C, and D antigen 病原体含有 A ， B ， C 和 D 抗原  The immune system identifies antigen A and mounts a strong defense  免疫系统识别抗原 A 并具有强大的防御能力  The pathogen then begins to use antigen B to infect cells: pathogen (virus) mutated  然后病原体开始使用抗原 B 感染细胞：病原体（病毒）发生突变  (3 minutes)

Host Defense failure ◦ The pathogen may use the cells of the immune system as hosts to prevent their destruction ◦ 病原体可以利用免疫系统的细胞作为宿主，以防止其破坏 ◦ The Mycobacterium tuberculosis (pathogen) become encapsulated by lysosome ◦ 结核分枝杆菌（病原体）被溶酶体包裹 ◦ Become walled off – lie dormant for a period of time – latency ◦ – 陷入困境潜伏一段时间 - 潜伏期 ◦ (6 minutes)

Host defense failure ◦ Pathogens may spark a robust immune response – but the body cannot keep that up forever ◦ 病原体可能会激发强大的免疫反应 - 但身体无法永远保持这种状态 ◦ Can lead to immunosuppression: 可能导致免疫抑制： ◦ During which time the pathogen continues to proliferate (grow) and can overwhelm the immune system ◦ 在此期间，病原体继续增殖（生长）并可能使免疫系统不堪重负 ◦ Worsening infection, disease, or disorder ◦ 感染，疾病或疾病恶化