Ultrastructural observations on peritoneal exudate cells from the striped bass

An ultrastructural study was conducted of the principal cells recovered from the peritoneal exudate of striped bass (Morone saxatilis) injected with killed Bacillus cereus. The most frequently observed cells were identified as macrophages, eosinophils, and neutrophils on the basis of comparing their structure with that reported for other fish species and higher vertebrates. All three of the types of cells were phagocytic; however, the numbers of bacteria engulfed were limited. Like other studies of this type in fish, the peritoneum of the striped bass proved to be a good source of cells for morphological investigations of phagocytosis.