The granular cells of Galleria mellonella during clotting and phagocytic reactions in vitro.

Light and electron-microscopic observations of the blood-cells (hemocytes) of the wax-moth Galleria mellonella showed that hemolymph coagulation was initiated by the rapid release of material from the granular cells. During incubation for short terms in vitro these cells showed progressive degranulation as material derived from the granules was discharged into the hemolymph. Attempts to determine the nature of this material by staining with ruthenium red proved mainly unsuccessful. When challenged with bacteria in vitro the granular cells failed to phagocytose these particles and instead the bacteria became embedded in the granular material surrounding these cells. The mode of coagulation reported here is compared with previous reports of the role of invertebrate hemocytes in hemolymph clotting.