title: Human T-lymphocyte growth factor: regulation of growth and function of T lymphocytes.
abstract: The discovery of T-cell growth factor (TCGF) has made it possible to now routinely grow in tissue culture normal and neoplastic human T cells for long periods and in large amounts. TCGF has been recently purified. It is a small protein released by a subset of mature T cells following lectin-antigen activation, which in turn acts upon other T-cell subsets that have developed specific receptors for TCGF after lectin-antigen stimulation. Thus, release of TCGF and development of receptors for it appear to be obligatory for the clonal expansion of all activated T cells. Unlike normal T cells, neoplastic T cells respond directly to TCGF, requiring no prior in vitro lectin-antigen activation. This has led to the development of several new cell lines from patients with T-cell leukemias and lymphomas. In some cases, these cells become independent of exogenous TCGF by producing their own growth factor, implying a role for TCGF in the continuous proliferation of these cells. These developments necessitate a reevaluation of some concepts of immunoregulation of T-cell activities in terms of production and response to TCGF. In addition, this information has clinical implications. Recent results have shown that a major defect of the athymic nude mouse is the inability to produce TCGF and that some immunosuppressive agents, such as glucocorticosteroids and cyclosporin-A, exert their effects on T cells by disrupting the TCGF-T-cell interaction. Some human immune deficiencies might be due to a failure to respond to or to produce TCGF, which in some cases might be corrected by exogenous TCGF.
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D002478:Cells, Cultured; D003470:Culture Media; D003602:Cytotoxicity, Immunologic; D006801:Humans; D007938:Leukemia / Q000276:immunology; D008213:Lymphocyte Activation; D008211:Lymphocyte Cooperation; D008222:Lymphokines / Q000302:isolation & purification / Q000502:physiology*; D008223:Lymphoma / Q000276:immunology; D051379:Mice; D010835:Phytohemagglutinins; D011975:Receptors, Mitogen; D013045:Species Specificity; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D003470:Culture Media; D008222:Lymphokines; D010835:Phytohemagglutinins; D011975:Receptors, Mitogen