title: Intracellular activation signal requirements for the induction of IL-2 responsiveness in resting T cell subsets in humans.
abstract: Activation signal requirements for the induction of the IL-2 responsiveness in purified subsets of human resting T cells, T4+ or T8+, have been investigated under the monocyte-depleted conditions. Substantial levels of IL-2 responsiveness were induced in T8+ cells by lectin, Con A, mAb directed against the CD3 Ag, OKT3, Ca2+ ionophore, ionomycin or phorbol ester, PMA. In contrast, none of these stimuli was by itself sufficient for the induction of IL-2 responsiveness in the T4+ subset. The latter cells could, however, be induced to respond to IL-2 by combinations of PMA plus either of Con A, OKT3, or ionomycin (but not any combination of Con A, ionomycin, and OKT3). These data indicate that induction of IL-2 responsiveness in the resting T4+ subset is more complex, possibly requiring two intracellular activation signals, increase in the concentration of intracellular Ca2+ and activation of protein kinase C, whereas either signal may directly trigger IL-2 responsiveness in the resting T8+ cells. The data further suggest that under optimal conditions, growth of both resting T4+ and T8+ subsets may be independent of monocytes.
authors.affiliation: Department of Internal Medicine, Shimane Medical University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Tsuchida
authors.forename: T
authors.initials: T
authors.lastname: Sakane
mesh_terms: D000911:Antibodies, Monoclonal / Q000502:physiology; D000945:Antigens, Differentiation, T-Lymphocyte; D001826:Body Fluids / Q000378:metabolism*; D002469:Cell Separation; D003208:Concanavalin A / Q000494:pharmacology; D004987:Ethers / Q000494:pharmacology; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology*; D007399:Interphase / Q000187:drug effects; D007424:Intracellular Fluid / Q000378:metabolism*; D015759:Ionomycin; D008213:Lymphocyte Activation / Q000187:drug effects; D010641:Phenotype; D013601:T-Lymphocytes / Q000145:classification / Q000276:immunology / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D004987:Ethers; D007376:Interleukin-2; D003208:Concanavalin A; D015759:Ionomycin; D013755:Tetradecanoylphorbol Acetate