Specific immune recognition of insect hemolin.

Bacteria entering the body cavities of insects are recognized by hemolymph components and subsequently inactivated by phagocytosis and nodule formation. A hemolymph component called hemolin is apparently involved in the recognition process. It binds to a bacterial surface molecule and forms a stable complex with other hemolymph proteins. Hemolin binding is independent of bacterial lipopolysaccharide (LPS) structure, whereas the complex formation is dependent on the presence of the carbohydrate moiety of LPS molecules. The specificity of immune recognition in insects is discussed.