The hemolytic activity of Galleria mellonella hemolymph

A hemolytic activity was identified in the hemolymph of normal and immune Galleria mellonella larvae. The hemolysin was active against sheep, human, guinea pig, and rabbit erythrocytes. Hemolysis occurred in the presence of 0.04M EDTA. Vaccination of the larvae with formalized Pseudomonas aeruginosa increased the hemolytic activity. The increase, and subsequent decline of this activity paralleled the pattern of induced in vivo antibacterial activity that is characteristic of the insect's immune response. The hemolytic activity was distinct from induced phospholipase A-like and phospholipase C-like activities that were detected in immune hemolymph and which were inhibited by EDTA. The hemolytically active material (HAM) was partially purified (apparent molecular weight range 69,000 to 75,000) and was found not to be antibacterial for P. aeruginosa. The physiological role of the HAM is as yet unknown. It is possible that it may act together with other hemolymph components to produce an immune state.