Regulation by interleukin 2 of interleukin 2 receptors and gamma- interferon synthesis by human thymocytes: augmentation of interleukin 2 receptors by interleukin 2

• Published in: The Journal of immunology (1950) Vol. 134; no. 2; pp. 953 - 958
• Main Authors: Reem, GH, Yeh, NH
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Am Assoc Immnol 01-02-1985; American Association of Immunologists
• Subjects: Adjuvants, Immunologic - physiology; Analysis of the immune response. Humoral and cellular immunity; Antibodies, Monoclonal - physiology; Antigens, Surface - immunology; Biological and medical sciences; Cell interactions; Child; Concanavalin A - pharmacology; Cyclosporins - pharmacology; Dexamethasone - pharmacology; Drug Synergism; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Humans; Immunobiology; Infant; Interferon-gamma - biosynthesis; Interleukin-2 - physiology; Lymphocyte Activation - drug effects; Receptors, Immunologic - biosynthesis; Receptors, Interleukin-2; T-Lymphocytes - metabolism; Tumor Necrosis Factor Receptor Superfamily, Member 7; Human; Regulation(control); Interleukin 2; Thymocyte; Production; Biosynthesis; Lymphokine; Lymphocyte; Gamma interferon; Biological receptor
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.134.2.953

The role of interleukin 2 (IL 2) on the expression of IL 2 receptors and on the synthesis of gamma-interferon (gamma-IFN) by human thymocytes was investigated. Human thymocytes isolated from specimens obtained during cardiac surgery of infants and children were induced with one or all of the following agents: IL 2, concanavalin A (Con A), and 12-O-tetradecanoylphorbol 13-acetate (TPA). The expression of IL 2 receptors and gamma-IFN titers were determined. The results indicate that thymocytes cultured in complete medium do not express receptors for IL 2, nor did IL 2 by itself induce the expression of IL 2 receptors. Con A induced the expression of IL 2 receptors by a moderate number of the thymocyte population and induced the synthesis of low amounts of gamma-IFN. Preincubation of thymocytes with TPA increased the response to Con A; both the number of thymocytes expressing receptors and the synthesis of gamma-IFN were increased. Addition of IL 2 to these cultures further augmented the expression of IL 2 receptors and gamma-IFN synthesis and resulted in the optimal expression of IL 2 receptors and maximal gamma-IFN synthesis. The expression of IL 2 receptors could be detected within 24 hr and preceded the induction of proliferation; it was therefore probably not due to the clonal expansion of a population of receptor-bearing thymocytes. Conversely, inhibition of IL 2 synthesis with dexamethasone (Dex) by thymocytes activated with Con A, or inhibition of the function of IL 2 receptors by anti-Tac, resulted in a decrease in the number of IL 2 receptor-bearing thymocytes activated with Con A, or inhibition of the function of IL 2 receptors by anti-Tac, resulted in a decrease in the number of IL 2 receptor-bearing thymocytes and of gamma-IFN synthesis. Thymocytes activated with TPA and Con A were more resistant to the inhibitory effects of Dex on the expression of IL 2 receptors than thymocytes activated with Con A alone. Maximal inhibition of the expression of IL 2 receptors and of gamma-IFN synthesis was achieved as a result of the synergistic effect of anti-Tac with Dex. Therefore, when IL 2 was prevented from binding to the receptors, and IL 2 synthesis was inhibited, the number of thymocytes expressing IL 2 receptors was sharply reduced and gamma-IFN synthesis was markedly inhibited.