An opsonin is any molecule that acts as a binding enhancer for the process of In phagocytosis (literally, cell eating), large particles are enveloped by the cell membrane of a (usually larger) cell and internalized to form a food vacuole. In animals, phagocytosis is performed by specialized phagocytotic cells or phagocytes, which serve to remove foreign bodies and thus fight infection. In vertebrates these include... phagocytosis. During the process of opsonization, An antigen is any molecule that is recognized by antibodies. An antigen that also triggers an immune response is called an immunogen. Usually, an antigen is a protein or a polysaccharide, but it can be any type of molecule, even small molecules if coupled to a large carrier (haptens). There... antigens are bound by Schematic of antibody binding to an antigen An antibody is a protein complex used by the immune system to identify and neutralize foreign objects like bacteria and viruses. Each antibody recognizes a specific antigen unique to its target. Nomenclature Antibodies are glycoproteins found in the blood and tissue fluids, as... antibody and/or The word complement (with an e in the second syllable, not to be confused with a different word, compliment with an i) has a number of uses. Generally a complement of X is something that together with X makes a complete whole; that supplies what X lacks. The first e... complement molecules. Phagocytic cells express receptors that bind opsonin molecules. With the antigen coated in these molecules, binding of the antigen to the phagocyte is greatly enhanced. Most phagocytic binding can not occur without opsonization of the antigen.

Furthermore, opsonization of the antigen and subsequent binding to an activated phagocyte will cause increased expression of complement receptors on neighboring phagocytes. Examples of opsonin molecules include the Schematic of antibody binding to an antigen An antibody is a protein complex used by the immune system to identify and neutralize foreign objects like bacteria and viruses. Each antibody recognizes a specific antigen unique to its target. Definition Antibodies or immunoglobulins (Ig) are glycoproteins found in the blood and... IgG antibody and the C3b, C4b, and iC3b components of the The complement system is a complex biochemical cascade of the immune system, leading to cytolysis, chemotaxis, opsonization and inflammation, it can mark pathogens for phagocytosis. It consists of more than 35 proteins. 12 which are directly involved in the complement pathways, while the rest have regulatory functions. There are three... complement system.