Kapingidza A Brenda, Kowal Krzysztof, Chruszcz Maksymilian
Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, 29208, USA.
Department of Allergology and Internal Medicine, Medical University of Bialystok, Bialystok, Poland.
Subcell Biochem. 2020;94:465-497. doi: 10.1007/978-3-030-41769-7_19.
In vertebrates, immunoglobulins (Igs), commonly known as antibodies, play an integral role in the armamentarium of immune defense against various pathogens. After an antigenic challenge, antibodies are secreted by differentiated B cells called plasma cells. Antibodies have two predominant roles that involve specific binding to antigens to launch an immune response, along with activation of other components of the immune system to fight pathogens. The ability of immunoglobulins to fight against innumerable and diverse pathogens lies in their intrinsic ability to discriminate between different antigens. Due to this specificity and high affinity for their antigens, antibodies have been a valuable and indispensable tool in research, diagnostics and therapy. Although seemingly a simple maneuver, the association between an antibody and its antigen, to make an antigen-antibody complex, is comprised of myriads of non-covalent interactions. Amino acid residues on the antigen binding site, the epitope, and on the antibody binding site, the paratope, intimately contribute to the energetics needed for the antigen-antibody complex stability. Structural biology methods to study antigen-antibody complexes are extremely valuable tools to visualize antigen-antibody interactions in detail; this helps to elucidate the basis of molecular recognition between an antibody and its specific antigen. The main scope of this chapter is to discuss the structure and function of different classes of antibodies and the various aspects of antigen-antibody interactions including antigen-antibody interfaces-with a special focus on paratopes, complementarity determining regions (CDRs) and other non-CDR residues important for antigen binding and recognition. Herein, we also discuss methods used to study antigen-antibody complexes, antigen recognition by antibodies, types of antigens in complexes, and how antigen-antibody complexes play a role in modern day medicine and human health. Understanding the molecular basis of antigen binding and recognition by antibodies helps to facilitate the production of better and more potent antibodies for immunotherapy, vaccines and various other applications.
在脊椎动物中，免疫球蛋白（Igs），通常被称为抗体，在抵御各种病原体的免疫防御武器库中发挥着不可或缺的作用。在抗原刺激后，抗体由分化的B细胞即浆细胞分泌。抗体有两个主要作用，包括与抗原特异性结合以启动免疫反应，以及激活免疫系统的其他成分来对抗病原体。免疫球蛋白对抗无数种不同病原体的能力在于它们能够区分不同抗原的内在能力。由于这种特异性以及对其抗原的高亲和力，抗体在研究、诊断和治疗中一直是一种有价值且不可或缺的工具。虽然抗体与其抗原结合形成抗原 - 抗体复合物看似是一个简单的过程，但它是由无数非共价相互作用组成的。抗原结合位点（表位）和抗体结合位点（互补决定区）上的氨基酸残基对维持抗原 - 抗体复合物稳定性所需的能量有密切贡献。研究抗原 - 抗体复合物的结构生物学方法是详细可视化抗原 - 抗体相互作用的极其有价值的工具；这有助于阐明抗体与其特定抗原之间分子识别的基础。本章的主要内容是讨论不同类别的抗体的结构和功能以及抗原 - 抗体相互作用的各个方面，包括抗原 - 抗体界面，特别关注互补决定区、互补决定区（CDRs）以及其他对抗原结合和识别重要的非CDR残基。在此，我们还将讨论用于研究抗原 - 抗体复合物的方法、抗体对抗原的识别、复合物中的抗原类型，以及抗原 - 抗体复合物在现代医学和人类健康中的作用。了解抗体对抗原结合和识别的分子基础有助于促进生产更好、更有效的抗体用于免疫治疗、疫苗和各种其他应用。
