Department of Microbiology and Immunology, Institute of Marine and Environmental Technology, University of Maryland School of Medicine, Baltimore, MD, United States.
Front Immunol. 2023 Aug 11;14:1245704. doi: 10.3389/fimmu.2023.1245704. eCollection 2023.
Germinal centers (GCs) are distinct microanatomical structures that form in the secondary lymphoid organs of endothermic vertebrates (i.e., mammals and some birds). Within GCs, B cells undergo a Darwinian selection process to identify clones which can respond to pathogen insult as well as affinity mature the B cell repertoire. The GC response ultimately generates memory B cells and bone marrow plasma cells which facilitate humoral immunological memory, the basis for successful vaccination programs. GCs have not been observed in the secondary lymphoid organs of ectothermic jawed vertebrates (i.e., fishes, reptiles, and amphibians). However, abundant research over the past decades has indicated these organisms can produce antigen specific B cell responses and some degree of affinity maturation. This review examines data demonstrating that the fundamentals of B cell selection may be more conserved across vertebrate phylogeny than previously anticipated. Further, research in both conventional mammalian model systems and comparative models raises the question of what evolutionary benefit GCs provide endotherms if they are seemingly unnecessary for generating the basic functional components of jawed vertebrate humoral adaptive immune responses.
生发中心（GCs）是内温动物（即哺乳动物和某些鸟类）次级淋巴器官中形成的独特的微观解剖结构。在 GCs 中，B 细胞经历达尔文选择过程，以识别能够对病原体侵袭做出反应以及亲和力成熟 B 细胞库的克隆。GC 反应最终产生记忆 B 细胞和骨髓浆细胞，促进体液免疫记忆，这是成功疫苗接种计划的基础。在外温动物（即鱼类、爬行动物和两栖动物）的次级淋巴器官中尚未观察到 GCs。然而，过去几十年的大量研究表明，这些生物体可以产生抗原特异性 B 细胞反应和一定程度的亲和力成熟。本综述检查了数据，这些数据表明，B 细胞选择的基本原理在脊椎动物进化中可能比以前预期的更为保守。此外，在传统的哺乳动物模型系统和比较模型中的研究提出了一个问题，如果 GCs 似乎对产生有颌脊椎动物体液适应性免疫反应的基本功能成分不是必需的，那么它们对内温动物有什么进化益处。
