体液vs Cell-Mediated Immunity
体液免疫和细胞介导的免疫是两种类型的adaptive immune responsethat enable the human body to defend itself in a targeted way against harmful agents such as bacteria, viruses and toxins. Whilst there is some overlap between these arms of the immune response - both rely on the functions of lymphoid cells - there are also some important differences.
如果使用以前暴露于相同感染的人的抗体给药,可以获得对特定感染或疾病的体液免疫力,从而避免了体液反应。然而,抗体介导的免疫涉及一组与细胞介导的免疫不同的分子成分和过程。在本文中,我们定义了体液免疫和细胞介导的免疫力,讨论了不同的免疫过程,目的和重要细胞类型。
体液与细胞介导的免疫力
体液免疫produces antigen-specific antibodies and is primarily driven by B cells. Cell-mediated immunity on the other hand does not depend on antibodies for its adaptive immune functions and is primarily driven by mature T cells, macrophages and the release of cytokines in response to an antigen.
什么是体液免疫?
体液免疫is an antibody-mediated response that occurs when foreign material -抗原- 在体内检测到。这种异物通常包括细胞外入侵者,例如细菌。这种机制主要由B细胞淋巴细胞,一种在检测特定抗原后产生抗体的免疫细胞。幼稚的B细胞是淋巴系统中循环的淋巴细胞。这些淋巴细胞表达了多种抗原特异性分子,这些分子对于检测人体传染剂必不可少。每当幼稚的B细胞在淋巴系统中遇到抗原时,它们就会经历一个分化过程,从而导致记忆B细胞和效应B细胞的产生。
A diagram showing humoral and cellular immunity.
在这differentiation,,,,memory B cells and effector B cells produce the same antigen-specific molecules as their parent naïve B cell. With the help of T cell lymphocytes, in turn activated by MHC class II receptors that recognize microbial-associated antigens, the activated memory B cells express these antigen-specific molecules on their surface while the effector B cells secrete these molecules in the blood to bind the antigen of interest.
How are antibodies produced?
当抗原结合位点与幼稚或记忆B细胞结合时,它会激活B细胞以产生和分泌更多抗原特异性抗体。B细胞完全成熟后,它被称为浆细胞,并将在其其余生命周期的其余部分中继续产生和分泌抗原特异性抗体。
抗体对病原体作用有何作用?
一旦抗体在血液中,这些自由浮动蛋白就可以作为具有直接和间接免疫功能的防御分子发挥作用。这些功能包括:
- neutralization of infectious agents – via blocking or antibody-dependent cellular cytotoxicity
- 补体系统的激活 - 补充依赖的细胞毒性
- binding of foreign substances to be destroyed - opsonization and phagocytosis
抗体主要通过附着和积累的机制中和抗原。例如,抗原匹配病毒颗粒上中和抗体的聚集将阻止该病毒感染其他细胞的能力。
抗体还可以通过激活补体级联反应或与效应细胞的相互作用以及细胞因子的释放,从而导致导致感染或抗原呈递细胞的裂解或杀死的过程。补体系统是先天免疫的一部分,可增强抗体和淋巴细胞清除病原体和感染细胞的能力。最后,涂层病原体或感染细胞的抗体可以吸引(调理),并在巨噬细胞中被巨噬细胞化。phagocytosis。
体液免疫取决于淋巴细胞以通过antibody-mediated functions,但这并不是涉及骨髓淋巴细胞的唯一自适应免疫力的形式。
What is cell-mediated immunity?
Unlike humoral immunity,,,, 细胞介导的免疫力不依赖其适应性免疫功能的抗体。细胞介导的免疫主要由成熟的T细胞,巨噬细胞和响应抗原的细胞因子释放驱动。T细胞involved in cell-mediated immunity rely on antigen-presenting cells that contain membrane-boundMHC I类蛋白质in order to recognize intracellular target antigens. The binding specificity between MHC proteins and foreign antigens is essential for the maturation and differentiation of naïve T cells into helper or killer T cells.
Cell-mediated immunity typically comes into play at body sites where cells are infected by a virus, bacteria, or fungi (intracellular invaders). With the assistance of MHC class I proteins, T cells can also recognize cancerous cells.
细胞介导的免疫涉及哪些淋巴细胞?
涉及细胞介导的免疫力的淋巴细胞的主要类型包括幼稚的T细胞,辅助T细胞,杀手T细胞和巨噬细胞。尚未激活的幼稚T细胞在血液和淋巴系统中循环。当它们遇到抗原呈递细胞时,这些幼稚的细胞被激活,迅速增殖成不同的T细胞亚群。这些子集执行不同的功能mso-fareast-font-family:Calibri;mso-fareast-theme-font:minor-latin;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:minor-bidi;
mso-ansi-language:EN-US;mso-fareast-language:EN-US;mso-bidi-language:AR-SA">-例如,CD4+辅助T细胞释放一组称为的信号蛋白细胞因子。这些细胞因子会直接损害靶细胞或帮助激活“杀手” T细胞和巨噬细胞。CD8+杀手T细胞,也称为细胞毒性T细胞,对靶细胞进行直接裂解,而巨噬细胞这是一种抗原呈递细胞,在T细胞激活中也起着重要作用。
体液与细胞介导的免疫力:表
体液 | 细胞介导 | |
类型 | Antibody-mediated response | T细胞介导的反应 |
活动部位 |
细胞外液体 |
抗原呈递组织的位置 |
Main Cell Types Involved |
B cells | T细胞 |
发作速度 |
Fast response upon detection | 反应慢 |
抗原类型 |
Extracellular pathogens | Intracellular pathogens, cancer cells |
去除方法 |
抗体介导的破坏或中和 |
细胞裂解和编程死亡 |
涉及的MHC蛋白 |
MHC II类蛋白 | MHC I类蛋白质 |