The clinical significance of mediators of cellular immunity.

This paper reviews experimental and clinical evidence for the existence of soluble mediators of cellular immune responses. Clinical appraisal of this field is now emerging from the stage of biological definition and technical development to the stage at which acceptable standards of mediator activity will now be required. The biological significance of these mediators may lie in amplification and regulation of the immunological response. The clinical significance of this field lies in the detection, assay and repair of genetic or non‐genetic disorders of cell‐mediated immunity. Development of this field will be much assisted by parallel studies of cell‐mediator function in both animals and man; and, with some optimism, may yield a predictive basis for control of the cellular immune response.