Jobson Sara, Hamel Jean-François, Mercier Annie
Department of Ocean Sciences, Memorial University, St. John's, Newfoundland, Canada.
Society for the Exploration and Valuing of the Environment, St. Philips, Newfoundland, Canada.
Fish Shellfish Immunol. 2022 Mar;122:352-365. doi: 10.1016/j.fsi.2022.02.009. Epub 2022 Feb 12.
The innate immunity of echinoderms has been a research focus since the early twentieth century, consistently providing ever deeper knowledge of its complexity and evolutionary aspects. At its core are coelomocytes, which are diverse cells collectively known to respond in a variety of ways, including via movement, phagocytosis, and aggregation. However, features of cellular immunity have never been compared in echinoderms from phylogenetic and distributional perspectives, to provide insight into ecological and evolutionary patterns. The present study catalyzed and characterized the formation of coelomocyte aggregates in members of all five extant classes of echinoderms. The morphological characteristics of these aggregates (including their colour, shape, texture, size) were assessed, as well as the major cells composing them. Coelomocyte diversity (both as free and aggregated forms) was determined to be maximum in class Holothuroidea, followed by Echinoidea, with the other classes showing similar levels of diversity. The colours of coelomocyte aggregates appeared to be more closely linked to phylogeny (classes, orders) rather than geographic range, or external colour of the species themselves. Asteroids and ophiuroids displayed primarily light-coloured aggregates, from transparent to green; while holothuroids, echinoids and crinoids demonstrated more vivid variants, from red to deep purple. The kinetics of aggregate formation and expulsion were monitored in selected species, showing immediate cellular response to foreign particulate matter in the form of encapsulation and various methods of expulsion, including through the dermal papillae of asteroids and the anus (cloaca) of holothuroids. The findings support that coelomocyte aggregate formation is a conserved immune response across all five extant classes of echinoderms with variations in their cell catalysts, complexity, shape, colour, and size.
自20世纪初以来，棘皮动物的先天免疫一直是研究重点，不断为其复杂性和进化方面提供更深入的认识。其核心是体腔细胞，这些细胞种类多样，已知能以多种方式做出反应，包括通过移动、吞噬作用和聚集。然而，从未从系统发育和分布角度对棘皮动物的细胞免疫特征进行过比较，以深入了解生态和进化模式。本研究促成并描述了所有五个现存棘皮动物纲成员中体腔细胞聚集体的形成。评估了这些聚集体的形态特征（包括颜色、形状、质地、大小）以及构成它们的主要细胞。确定体腔细胞多样性（以游离和聚集形式）在海参纲中最大，其次是海胆纲，其他纲显示出相似的多样性水平。体腔细胞聚集体的颜色似乎与系统发育（纲、目）的联系更为紧密，而非地理范围或物种本身的外部颜色。海星纲和蛇尾纲主要呈现浅色聚集体，从透明到绿色；而海参纲、海胆纲和海百合纲则表现出更鲜艳的变体，从红色到深紫色。在选定物种中监测了聚集体形成和排出的动力学，显示细胞对异物颗粒物质立即做出反应，表现为包囊化以及各种排出方法，包括通过海星纲的皮鳃和海参纲的肛门（泄殖腔）。这些发现支持体腔细胞聚集体形成是所有五个现存棘皮动物纲共有的免疫反应，只是在细胞催化剂、复杂性、形状、颜色和大小方面存在差异。
