An antibody in blood serum that attaches to invading microorganisms and other antigens to make them more susceptible to the action of phagocytes

Wiktionary Word definitions in Wiktionary
n. Any antibody that causes an invading species to be more susceptible to phagocytosis

WordNet Word definitions in WordNet
n. an antibody in blood serum that attaches to invading microorganisms and other antigens to make them more susceptible to the action of phagocytes

Wikipedia Word definitions in Wikipedia
An opsonin (from the Greek opsōneîn , to prepare for eating) is any molecule that enhances phagocytosis by marking an antigen for an immune response or marking dead cells for recycling (i.e., causes the phagocyte to "relish" the marked cell). Opson in ancient ...