[The cell mediated immune response].

T-lymphocytes are the most important regulatory cells of the immune system and mediate a number of crucial effector functions. The T-lymphocyte antigen receptor recognises peptide antigen bound to so-called Major Histocompatibility Complex (MHC) molecules on the surface of the target cell. Activation of CD8-positive cytotoxic T-lymphocytes leads to lysis of the antigen presenting cell, whereas activation of CD4-positive T-helper lymphocytes results in release of regulatory and stimulatory cytokines. In this review, the results of recent years' research in the function of the cell mediated immune system is presented, followed by an overview of the role played by the mediated immune system in protection against infectious disease, cancer, or as a cause of immune-mediated pathology and autoimmunity.