title: Enzyme release assay of human NK cell activity using beta-galactosidase-expressing K562 target cell line.
abstract: In the present report, we established a K562 cell line useful for an enzyme release assay of human natural killer (NK) activity. Human myelogenous leukemia cell line, K562, was transfected with a plasmid carrying Escherichia coli beta-galactosidase (beta-gal) gene. A colony that permanently expresses the enzyme activity was isolated, and designated K562/Zneo. Incubation of K562/Zneo cells (1 x 10(4)) with nonadherent human peripheral blood lymphocytes (PBL) resulted in the release of beta-gal activity depending on the incubation time and the number of effector cells. Released beta-gal activity was assayed sensitively by using 4-methylumbelliferyl-beta-D-galactoside, a fluorescent substrate. The cytolytic activity of PBL was augmented significantly when the cells were preincubated with interleukin-2 for 20 h. This enzyme release assay showed a comparable sensitivity to that of 51Cr release assay. Thus, K562/Zneo cell line is thought to be useful for the nonradioactive assay of human NK and lymphokine-activated killer activities.
authors.affiliation: Department of Biotechnology, Faculty of Engineering, Okayama University, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ohmori
authors.forename: H
authors.initials: H
authors.lastname: Ikeda
authors.forename: T
authors.initials: T
authors.lastname: Tanigawa
authors.forename: T
authors.initials: T
authors.lastname: Takai
authors.forename: M
authors.initials: M
authors.lastname: Hikida
mesh_terms: D003602:Cytotoxicity, Immunologic; D006801:Humans; D007111:Immunity, Cellular; D066298:In Vitro Techniques; D007694:Killer Cells, Natural / Q000276:immunology*; D007951:Leukemia, Myeloid; D014162:Transfection; D014407:Tumor Cells, Cultured; D001616:beta-Galactosidase / Q000235:genetics*
chemical_list: D001616:beta-Galactosidase