title: Proliferative effects of 12-O-tetradecanoylphorbol-13-acetate (TPA) and calcium ionophores on human large granular lymphocytes (LGL).
abstract: The proliferative responses of natural killer (NK) cells to 12-O-tetradecanoylphorbol-13-acetate (TPA), which directly activates protein kinase c(PKC), and to the Ca2+ ionophores A23817 and ionomycin, known to enhance the intracellular calcium, have been investigated. Highly purified large granular lymphocytes (LGL) were cultured for 12-30 hr in the presence of TPA, ionomycin, or A23817. TPA alone (1-20 ng/ml) triggered rapid LGL proliferation, whereas the calcium ionophores were ineffective. The addition of either calcium ionophore to suboptimal doses or TPA (0.1-0.5 ng/ml) resulted in a synergistic effect on LGL proliferation. Under these conditions high levels of IL-2 activity were released by the LGL. Phenotypic analysis revealed the rapid loss of the Fc gamma receptors (CD16) on LGL and the induction of the expression of IL-2 (CD25) and transferrin receptors and of HLA-DR, but not of CD3. Removal of extracellular Ca2+ by addition of EGTA at the beginning of the culture greatly depressed LGL proliferation and IL-2 production, and blocked phenotypic changes, such as the expression of Tac antigen. Finally, progression to the proliferative phase of LGL, activated by TPA alone or with ionomycin, was completely abrogated by a hyperimmune anti-IL-2 antiserum.
authors.affiliation: Department of Experimental Medicine, Università La Sapienza, Rome, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Procopio
authors.forename: A
authors.initials: A
authors.lastname: Gismondi
authors.forename: R
authors.initials: R
authors.lastname: Paolini
authors.forename: S
authors.initials: S
authors.lastname: Morrone
authors.forename: R
authors.initials: R
authors.lastname: Testi
authors.forename: M
authors.initials: M
authors.lastname: Piccoli
authors.forename: L
authors.initials: L
authors.lastname: Frati
authors.forename: R B
authors.initials: RB
authors.lastname: Herberman
authors.forename: A
authors.initials: A
authors.lastname: Santoni
mesh_terms: D000954:Antigens, Surface / Q000032:analysis; D000001:Calcimycin / Q000494:pharmacology*; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D004357:Drug Synergism; D004533:Egtazic Acid / Q000494:pharmacology; D004987:Ethers / Q000494:pharmacology; D006801:Humans; D007106:Immune Sera / Q000494:pharmacology; D007166:Immunosuppressive Agents / Q000494:pharmacology; D007376:Interleukin-2 / Q000096:biosynthesis / Q000276:immunology; D015759:Ionomycin; D007694:Killer Cells, Natural / Q000145:classification / Q000166:cytology / Q000187:drug effects*; D007700:Kinetics; D008213:Lymphocyte Activation / Q000187:drug effects*; D010641:Phenotype; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7
chemical_list: D000954:Antigens, Surface; D004987:Ethers; D007106:Immune Sera; D007166:Immunosuppressive Agents; D007376:Interleukin-2; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7; D000001:Calcimycin; D004533:Egtazic Acid; D015759:Ionomycin; D013755:Tetradecanoylphorbol Acetate