Comparative pathology of marine invertebrates and the study of human disease

Abstract

<h2>Summary</h2> Studies on an infection with gram-negative bacteria in <i>Limulus</i> led to the discovery of the extreme sensitivity of the amebocytes to gram-negative endotoxin. This led to the development of a method for measuring very small amounts of endotoxin in biologic fluids and in human blood. Yet, had the original observation of Cantacuzène on the large common edible spider crab (<i>Maia</i>) been followed, this remarkable sensitivity of marine arthropod blood to endotoxin would have been recognized much earlier. The original work of Metchnikoff on sea star larvae stimulated him to develop the major theory of phagocytosis but, until the adult animal of the same genus was reexamined half a century later, the presence of a powerful substance which selectively inhibits growth of lymphocytes following primary immunization remained unknown. Though mucus secretion is a fundamental characteristic of most invertebrate phyla and all vertebrates, little is known about the regulatory mechanism of the secretory process; studies of the responses of specialized invertebrate secretory cells to infection, first recognized by Cantacuzène, have now led to a new means of studying macromolecular control of mucus secretion in man. These three stories emphasize the continuing need to study disease as a biologic phenomenon, with curiosity alone as the main stimulus.