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 the lymphoid organs by involving diverse tissue-specific adhesion molecules on lymphocytes (called, homing receptors) and on endothelial cells (called, vascular addressins). Free lymphocytes constantly recirculate in blood after their re-entry from lymphoid tissue, via lymphatic and throacic ducts. This happens with the purpose that full repertoire of antigenic specificities of lymphocytes is continuously represented throughout the human or animal body. Homing happens in tissue-specific manner, e.g., B lymphocytes migrate better to mucosa-associated lymphoid tisse (Peyer's patches), and T lymphocytes preferentially to the peripheral lymph nodes.