[The function of different lymphocyte groups and methods for their separation (author's transl)]

A review is given of the participation of T- and B-lymphocytes in the three most important lymphocyte functions: antibody formation, cellular effector reactions, especially cytotoxicity and regulator functions, with particular reference to the concept of "lymphocyte population". The most commonly used methods for the separation of T- and B-lymphocytes and of lymphocytes with the same function are described.