棘皮动物免疫学研究进展

棘皮动物属原始后口动物、无脊椎动物的最高等类群，它处于由无脊椎动物向脊椎动物开始分支进化的阶段．研究棘皮动物的免疫功能和作用机理，对从比较免疫学角度探讨动物免疫系统进化过程有承前启后的重要意义．因此，有必要对棘皮动物的免疫学研究进展作一个较全面的综述，并理清未来的研究热点和方向．棘皮动物与其他无脊椎动物一样具有先天性免疫系统，但未发现脊椎动物所具有的获得性免疫．其免疫应答是由参与免疫反应的效应细胞——体腔细胞和多种体液免疫因子共同介导的．比较免疫学分析表明，棘皮动物存在脊椎动物补体系统的替代途径和凝集素途径，但未发现经典途径和明确的终端途径．棘皮动物先天性免疫系统存在数量庞大的基因家族．今后应加强对未知免疫相关基因、蛋白质、信号传导途径及效应分子的研究，回答免疫系统的起源、功能和进化等问题．

The evolution of echinoderm immunology

Echinoderms are deuterostome, and occupy the top taxonomic position of invertebrates, where is the evolutionary linkage between invertebrates and vertebrates. This is a critical phylogenetic vantage point to infer both the early evolution of bilaterian immunity and the underpinnings of the vertebrate adaptive immune system. The available published literatures on echinoderm immunological mechanisms are compiled and discussed here to understand its evolution process and the hot spots or directions in future investigations. Echinoderms have an innate immune system like vertebrates but their adaptive attributes have not been observed. Its immune responses are based on coelomocytes activity working in parallel with a variety of humoral factors that react directly with invading pathogens. Comparative studies of immune functions in echinoderms have demonstrated that there is a complement system in echinoderms that appears to have alternative pathway and lectin pathway but lack classical pathway and terminal pathway. The sea urchin innate immune system has a number of large gene families. Further investigations are needed to understand the unknown immune-associated genes, proteins, immune signaling pathways and effector molecules, and to know the origin, the underlying mechanisms and evolution of innate immune system.