Cytokine signal networks and a new era in biomedical research.

Elucidation of the biochemical nature of the signal transduction pathway that regulate transcription and replication is the focus of attention in molecular biology. This research may make feasible manipulation of growth and differentiation of mammalian cells, which in turn would have profound implication in biomedical research on cell and gene therapy, and development of pharmaceutical products. Cytokines control growth, differentiation, death, and function of cells of lymphocytic, hemopoietic systems, and together with nerve cells provide a pertinent model to study intercellular communications and intercellular signal networks. This review outlines general features of signal transduction and several aspects of cytokine networks are discussed with emphasis on: transcriptional regulation of Th1 and Th2-specific cytokine genes in T cells, the roles of cytokines and their receptors in growth and differentiation of hemopoietic cells, and the manipulation of cytokine networks.