Classification and Immune Function of Coelomocytes in Echinoderms

Abstract: The top taxonomic position among non-chordate invertebrates, which make up the evolutionary connection between invertebrates and vertebrates, is held by echinoderms. Their immune responses rely on coelomocyte activity functioning concurrently with a range of humoral components that directly interact with invasive pathogens. However, markedly lower numbers of systematic reviews of the classification and immune function of coelomocytes have been performed compared with those of vertebrates. Studying echinoderm coelomocytes continues to be an important evolutionary vantage point for determining the origins of bilaterian immunity as well as the principles behind the adaptive immune system of vertebrates. This article reviews the classifications and immune functions of coelomocytes (sea urchin, sea cucumber and sea star). It summarizes the research progress on immune-related genes/proteins, signal transduction pathways and effector molecules in echinoderms according to the recent literature. This summary provides a theoretical basis for studying coelomocytes and disease control in echinoderms. In the future, a variety of methods and techniques should be used and combined with the surface receptors of cells to study the classification and function of coelomocytes of echinoderms.