The knowledge on echinoderm coelomocytes has increased in recent years, but researchers still face a complex problem: how to obtain purified cells. Even flow cytometry being useful to address coelomocytes in suspension, the need for a method able to provide isolated cells is still noteworthy. Here, we use Imaging Flow Cytometry (IFC) to characterize the coelomocytes of two sea urchin species – Arbacia lixula and Lytechinus variegatus – and obtain gates to isolate cell populations. Then, we used these gates to study the physiological response of A. lixula coelomocytes during an induced immune challenge with Escherichia coli. An analysis of area and aspect ratio parameters of the flow cytometer allowed the identification of two main cell populations in the coelomic fluid: circular and elongated cells. A combination of this method with nucleus labeling using propidium iodide allowed the determination of gates containing isolated subpopulations of vibratile cells, red spherulocytes, and two phagocytes subpopulations in both species. We observed that during an induced bacterial immune challenge, A. lixula was able to modulate coelomocyte frequencies, increasing the phagocytes and decreasing red spherulocytes and vibratile cells. These results indicate that vibratile cells and red spherulocytes act by immobilizing and stoping bacterial growth, respectively, cooperating with phagocytes in the immune response. The use of IFC was fundamental not only to identify specific gates for the main coelomic subpopulations but also allowed the investigation on how echinoids modulate their physiological responses during immune challenges. Furthermore, we provide the first experimental evidence about the role of vibratile cells, corroborating its involvement with the immune system.

近年来，关于棘皮动物腔皮细胞的知识有所增加，但是研究人员仍然面临一个复杂的问题：如何获得纯化的细胞。即使流式细胞仪可用于解决悬浮液中的内皮细胞，仍然需要一种能够提供分离细胞的方法。在这里，我们使用成像流式细胞仪（IFC）来表征两种海胆物种–螺旋藻和变异三角藻（Lytechinus variegatus）的内皮细胞，并获得隔离细胞种群的门。然后，我们使用这些门来研究螺旋藻诱导的大肠杆菌免疫攻击过程中的螺旋体结肠细胞的生理反应。通过对流式细胞仪的面积和长宽比参数的分析，可以鉴定出结肠流体中的两个主要细胞群：圆形和细长细胞。将该方法与使用碘化丙啶进行核标记相结合，可以确定两个物种中包含分离的亚群的可动细胞，红色球细胞和两个吞噬细胞亚群的门。我们观察到在诱导的细菌免疫攻击中，力克力曲霉能够调节内皮细胞的频率，增加吞噬细胞并减少红色球细胞和振动细胞。这些结果表明，在免疫应答中，可吞噬细胞和红色球细胞分别通过固定和停止细菌生长来起作用，并与吞噬细胞协同作用。使用IFC不仅是识别主要Coelomic亚群的特定门的基础，而且还允许研究类脂蛋白如何在免疫激发过程中调节其生理反应。此外，我们提供了有关振动细胞作用的第一个实验证据，证实了其与免疫系统的关系。