title: Synergistic effects of phorbol ester and interferon-alpha: target cell class I HLA antigen expression and resistance to natural killer and lymphokine-activated killer cell-mediated cytolysis.
abstract: This study was undertaken to investigate whether target cell class I HLA antigen expression induced by phorbol ester and interferon-alpha (IFN-alpha) was associated with resistance to natural killer (NK) cells and lymphokine-activated killer (LAK) cell-mediated cytotoxicity. Class I antigen expression on the surface of the K562 erythroleukemia cell line was enhanced by either IFN-alpha or phorbol ester (PDBu). Addition of PDBu together with IFN-alpha had a synergistic effect on class I antigen expression on the cells. Furthermore, synergism between IFN-alpha and PDBu was also found in class I antigen expression by MOLT-3 cells. This synergistic effect on class I antigen expression was blocked by the protein synthesis inhibitor (cycloheximide). Pretreatment of K562 cells with PDBu and IFN-alpha made them more resistant to lysis by NK and LAK cells than did either PDBu or IFN-alpha. In contrast to PDBu, 4 alpha PDD, a biologically inactive phorbol analogue, alone or combination with IFN-alpha, had no effect on class I antigen expression and susceptibility to lysis by NK and LAK cells. Kinetic experiments showed an inverse relationship between the expression of class I antigens and susceptibility to NK cell-mediated cytolysis. Using cold target competition analysis, target cells pretreated with PDBu and IFN-alpha clearly competed less effectively than did untreated cells for lysis of untreated target cells. These results demonstrate that target cells pretreated with PDBu and IFN-alpha decrease their sensitivity to natural killer and lymphokine-activated killer cells inversely with target cell class I HLA antigen expression.
authors.affiliation: First Department of Internal Medicine, Nagasaki University School of Medicine, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Migita
authors.forename: K
authors.initials: K
authors.lastname: Eguchi
authors.forename: I
authors.initials: I
authors.lastname: Akiguchi
authors.forename: H
authors.initials: H
authors.lastname: Ida
authors.forename: A
authors.initials: A
authors.lastname: Kawakami
authors.forename: Y
authors.initials: Y
authors.lastname: Ueki
authors.forename: A
authors.initials: A
authors.lastname: Kurata
authors.forename: T
authors.initials: T
authors.lastname: Fukuda
authors.forename: S
authors.initials: S
authors.lastname: Nagataki
mesh_terms: D002460:Cell Line; D003080:Cold Temperature; D003602:Cytotoxicity, Immunologic / Q000187:drug effects*; D004357:Drug Synergism; D015395:Histocompatibility Antigens Class I / Q000032:analysis*; D006801:Humans; D007370:Interferon Type I / Q000494:pharmacology*; D015979:Killer Cells, Lymphokine-Activated / Q000276:immunology*; D007694:Killer Cells, Natural / Q000276:immunology*; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology*
chemical_list: D015395:Histocompatibility Antigens Class I; D007370:Interferon Type I; D015240:Phorbol 12,13-Dibutyrate