Lymphocyte homing receptors are cell adhesion molecules which target addressins. Lymphocyte homing refers to adhesion of the circulating lymphocytes in blood to specialized endothelial cells within lymphoid organs, facilitated by diverse tissue-specific adhesion molecules on lymphocytes (homing receptors) and on endothelial cells (vascular addressins).
Free lymphocytes constantly recirculate in blood after their re-entry from lymphoid tissue, via lymphatic and thoracic ducts. This happens so that the full repertoire of antigenic specificities of lymphocytes is continuously represented throughout the body. Homing happens in tissue-specific manner—e.g. B lymphocytes migrate better to mucosa-associated lymphoid tissue (Peyer's patches), and T lymphocytes preferentially to the peripheral lymph nodes.