CYTOLYSIS OF HEMOCYTES INDUCED BY SERUM AND PLASMA IN 3 CRUSTACEANS, PANULIRUS-JAPONICUS, PENAEUS-JAPONICUS, AND HOMARUS-AMERICANUS

The effects of serum and/or plasma of three crustacean species on cellular morphology of homologous and heterologous hemocytes were observed using an in vitro short-term culture system. When hemocytes of the spiny lobster, Panulirus japonicus, isolated from hemolymph were mixed with serum of the same species, rapid cytolysis occurred in hyaline and semigranular cells. Plasma of Panulirus japonicus dialyzed against artificial sea water (dialyzed plasma) had the same cytolytic effect on hyaline and semigranular cells. Although the granular cells are not lysed, exposure to serum and plasma does produce changes in morphology and behavior (adhesion and spreading). Dialyzed plasma of the shrimp (Penaeus japonicus) and the lobster (Homarus americanus) also showed the same phenomena on homologous hemocytes. Dialyzed plasma of these three species had a less pronounced cytolytic effect on heterologous hemocytes. The cytolytic activity of the dialyzed plasma was weakened by heat treatment and inactivated by protease treatment. These results suggest that a protein factor(s) that specifically induces bursting of hyaline and semigranular cells exists in plasma of crustaceans.