Mechanisms of lymphocyte traffic and cell targeting

Several concepts in the immunotherapy of cancer aim to exploit the powerful cellular effector mechanisms of the immune system. In contrast to antibodies and other soluble agents, cells do not distribute randomly with the circulation but have their own program of trafficking through the body and entering the various organs. Some characteristics of migration and homing of different populations of lymphocytes as well as the molecular mechanisms governing lymphocyte entry into tissues are discussed here in order to delineate problems and prospects in targeting cell populations into specific organs.