As central effectors of the adaptive immune response, immunoglobulins, or antibodies, provide essential protection from pathogens through their ability to recognize foreign antigens, aid in neutralization, and facilitate elimination from the host. Mammalian immunoglobulins can be classified into five isotypes—IgA, IgD, IgE, IgG, and IgM—each with distinct roles in mediating various aspects of the immune response. Of these isotypes, IgA and IgM are the only ones capable of multimerization, arming them with unique biological functions. Increased valency of polymeric IgA and IgM provides high avidity for binding low-affinity antigens, and their ability to be transported across the mucosal epithelium into secretions by the polymeric immunoglobulin receptor allows them to play critical roles in mucosal immunity. Here we discuss the molecular assembly, structure, and function of these multimeric antibodies.

中文翻译：

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IgM 和 IgA 多聚体组装的分子机制

作为适应性免疫反应的核心效应物，免疫球蛋白或抗体通过识别外来抗原、帮助中和并促进从宿主中消除的能力，提供针对病原体的基本保护。哺乳动物免疫球蛋白可分为五种同种型：IgA、IgD、IgE、IgG 和 IgM，每种同种型在介导免疫反应的各个方面具有不同的作用。在这些同种型中，IgA 和 IgM 是唯一能够多聚化的同种型，从而赋予它们独特的生物学功能。聚合 IgA 和 IgM 效价的增加提供了结合低亲和力抗原的高亲和力，并且它们通过聚合免疫球蛋白受体转运穿过粘膜上皮进入分泌物的能力使它们在粘膜免疫中发挥关键作用。在这里，我们讨论这些多聚抗体的分子组装、结构和功能。