[The immune system: hormones and mediators].

Hormones and mediators of the immune system influencing the growth, differentiation and effector functions of immunocompetent cells, were described. Lymphokines and monokines produced by lymphocytes and cells of a monocytic series in response to antigenic stimulation, mediate intercellular interrelationships in the process of development of immune reactions, thus providing for intersystemic regulation. Mediators of the central immunity organs, thymus peptides and bone marrow peptides (myelopeptides) influence the formation and normal functioning of T and B lymphocytes. Peptides with opiate-like properties were detected among bone marrow mediators. The involvement of thymus and bone marrow mediators in intersystemic interrelationships is discussed.