Meeting Abstract

P3.126  Sunday, Jan. 6  Can enzyme histochemistry identify the immune cells of the octocoral Swiftia exserta? MENZEL, L.P.*; BIGGER, C.H.; Florida International University lorenzo.menzel@fiu.edu

Most animals rely on circulating hemocytes (leukocytes in mammals) as cellular effectors of their immune system. These cells have traditionally been characterized based on morphology, function, and/or cellular contents/products. Morphological descriptions utilize granular sizes, shapes, and abundancy, and cell shapes; functional descriptions rely mainly on phagocytic ability and oxygen transport; while cellular content descriptions include cytochemical features and an array of enzymes.
Some of the key enzymes have become standard identifiers of phagocytic cells in tissues, e.g., hydrolytic enzymes, peroxidase, and, in invertbrates, phenoloxidase. Sudan black, neutral red, and several histological stain combinations (Wright’s stain, Ehrlich’s trichrome, Mallory’s connective tissue) have been used for cytochemical differentiation of hemocytes.
Cnidaria, such as our model animal Swiftia exserta, lack a circulatory system making the isolation and characterization of immune effectors cells more challenging. To date a cell type termed the “granular amoebocyte” (clearly a purely morphological description) has been the suggested “immunocyte” (possibly a mixed cell population). In order to identify and characterize the immune effector cells in S. exserta we employed several classical enzyme histochemistry techniques for sub-cellular (histological and ultrastructural) localization of phosphatases, peroxidases, phenoloxidase, and mono-amine oxidase. In addition, we utilized several cytochemical methods (periodic acid-Schiff, sudan black, neutral red, and Wright’s stain) to characterize these cells. The results with these staining techniques allow us to characterize the putative “immunocytes” in anthozoans.