Size Selectivity in Removal of Pathogens from the Blood of the American Lobster, Homarus americanus

Abstract

In the digestive gland of Homarus americanus, the American lobster, fixed phagocytes play an important role in the removal of foreign particles from the blood. Though the American lobster's immune system is not fully understood, fixed phagocytes have been shown to uptake foreign particles including injected carbon particles, latex microspheres, and some types of bacteria. It is predicted that there are limitations of uptake due to size and type of foreign particle. This experiment uses different sized fluorescent yellow-green carboxylate microsphere suspensions to determine possible size limitations of uptake to fixed phagocytes. Though there are no known viral agents known to affect the American lobster, an infectious pancreatic necrosis virus suspension was injected into the blood to determine if fixed phagocytes could ever protect the lobster from a virus. Fluorescent light microscopy and transmission electron microscopy were used to investigate the removal of microspheres and viral particles.