STUDIES ON CELL CELL COOPERATION DURING PHAGOCYTOSIS BY PURIFIED HEMOCYTE POPULATIONS OF THE WAX MOTH, GALLERIA-MELLONELLA

Improvements in the purification of Galleria mellonella haemocytes using Percoll gradients are described. This procedure resulted in 95% purity for plasmatocytes, 89% for granular cells and 69% for spherule cells. Using unwashed haemocytes taken directly off the Percoll gradients for making monolayers showed that calcium ion concentration, incubation time and temperature affect the number of cells attaching to the glass coverslips. The inability of these unwashed cells to undertake phagocytosis is discussed. In contrast, separated and washed haemocytes were highly phagocytic although ingestion was confined to the plasmatocyte cell type. Maximal ingestion by the plasmatocyte was, however, obtained only after the readdition of the granular cells to the plasmatocyte monolayer, illustrating the necessity for cell-cell co-operation in this process. The presence of prophenoloxidase in the granular cell type alone indicates that this system may be involved in the haemocyte co-operation process.