Several immune molecules are produced and stored in the granules of hemocytes before being released into the hemolymph upon activation by bacterial and/or fungal cellwall components, such as peptidoglycan (PG), lipopolysaccharides (LPS) and b-glucans (BGs).
Pattern recognition proteins (PRPs) or pattern recognition receptors (PRRs) recognize and bind the microbial cell wall components and activate various immune responses.