Gross P S, Al-Sharif W Z, Clow L A, Smith L C
Department of Biological Sciences, George Washington University, Washington, DC 20052, USA.
Dev Comp Immunol. 1999 Jun-Jul;23(4-5):429-42. doi: 10.1016/s0145-305x(99)00022-1.
Our understanding of inflammatory responses in humans has its roots in the comparative approach to immunology. In the late 1900s, research on echinoderms provided the initial evidence for the importance of phagocytic cells in reactions to foreign material. Studies of allograft rejection kinetics have shown that echinoderms have a non-adaptive, activation type of immune response. Coelomocytes mediate the cellular responses to immune challenges through phagocytosis, encapsulation, cytotoxicity, and the production of antimicrobial agents. In addition, a variety of humoral factors found in the coelomic fluid, including lectins, agglutinins, and lysins, are important in host defense against pathogens and other foreign substances. Recently, a simple complement system has been identified in the purple sea urchin that is homologous to the alternative pathway in vertebrates. The sea urchin [corrected] homologue of C3, is inducible by challenge with lipopolysaccharide, which is known to activate coelomocytes. Complement components have been identified in all vertebrate classes, and now have been characterized in protochordates and echinoderms indicating the primordial nature of the complement system. Because it is thought that the complement system evolved from a few primordial genes by gene duplication and divergence, the origin of this system appears to have occurred within the common ancestor of the deuterostomes.
我们对人类炎症反应的理解源于免疫学的比较研究方法。在20世纪后期，对棘皮动物的研究为吞噬细胞在对外来物质反应中的重要性提供了初步证据。同种异体移植排斥动力学研究表明，棘皮动物具有非适应性、激活型免疫反应。体腔细胞通过吞噬作用、包囊化、细胞毒性和抗菌剂的产生介导对免疫挑战的细胞反应。此外，在体腔液中发现的多种体液因子，包括凝集素、凝集素和溶素，在宿主抵御病原体和其他外来物质方面起着重要作用。最近，在紫海胆中发现了一种简单的补体系统，它与脊椎动物的替代途径同源。海胆C3的同源物可通过脂多糖刺激诱导产生，脂多糖已知可激活体腔细胞。补体成分已在所有脊椎动物类别中被鉴定出来，现在也已在原索动物和棘皮动物中得到表征，这表明补体系统具有原始性质。由于人们认为补体系统是通过基因复制和分化从一些原始基因进化而来的，所以这个系统的起源似乎发生在后口动物的共同祖先中。
