Opsonisation
The term opsonisation comes from the Greek ‘opsōneîn’, meaning “to prepare for eating”. Opsonisation within the immune system refers to the binding of an opsonin, or ‘tag’, to an invading cell or organism. Examples of opsonins include complement proteins (especially C3b), antibodies, and some plasma proteins. The binding of an opsonin to the chosen target enhances the efficiency of phagocytosis, by increasing the likelihood of binding occurring between a phagocyte and a pathogen. This is achieved by increasing the number of binding sites available to the phagocyte, and also by reducing the repellent negative charge that exists at the surface of all cells. Reducing or overcoming this negative charge between the phagocyte and the pathogen allows the phagocyte to approach them more effectively.
