Opsonin

Definition

Opsonin is a molecule that enhances phagocytosis by marking an antigen for an immune response. It binds to the surface of pathogens, making them more recognizable and easier to engulf by phagocytes.

5 Must Know Facts For Your Next Test

1. Opsonins include antibodies and complement proteins like C3b.
2. They are crucial in the immune system's ability to target and eliminate pathogens.
3. Opsonization is the process by which opsonins coat pathogens to enhance their uptake by phagocytes.
4. The Fc region of antibodies can function as an opsonin by binding to Fc receptors on phagocytes.
5. Deficiencies in opsonins or their receptors can lead to increased susceptibility to infections.

Related terms

Phagocytosis:

The process by which cells ingest and destroy pathogens or debris.

Complement System:

A group of proteins in blood plasma that enhance immune responses, including acting as opsonins.

Antibody:

A protein produced by B-cells that recognizes and binds to specific antigens, sometimes acting as an opsonin.