Helix pomatia lectin and annexin V, two molecular probes for insect microparticles: possible involvement in hemolymph...

Insect hemolymph coagulation involves a complex reaction with contributions from hemocytes and soluble factors. Here we present evidence for the presence of microparticles in the coagulation reaction. These particles are formed by hemocytes in a calcium-dependent process. Both the particles and the remaining cells are labelled by annexin V indicating the presence of phosphatidylserine on the outer membrane. Microparticles are enriched in hemomucin, a surface protein of Drosophila hemocytes that is specifically recognised by a snail (Helix pomatia) lectin. Hemomucin is shown to bind to lipophorin, a multifunctional hemolymph molecule previously implied in coagulation. Our findings suggest similarities at a biochemical and cellular level between vertebrate blood and insect hemolymph coagulation.