Receptor (immunology)

A receptor in immunology is a molecule on the surface of an immunocyte (a cell of the immune system) which binds its ligand (a molecule of some sort; from Latin 'ligandum', an item which is to be bound).

Examples of these receptors include:
 * a B cell receptor specifically binding an antigen
 * a T cell receptor, specifically binding a complex of major histocompatibility molecule and antigenic peptide
 * a cytokine receptor, interleukin receptor or chemokine receptor and its ligand