title: [Mechanism of cloned human lymphokine-activated killer (LAK) cells killing human leukemia cells in vitro].
abstract: The killing of human leukemia cells by cloned human LAK cell was investigated with 51Cr release, semisolid agar colony-formation and MTT assay. Human LAK cells were generated and cloned from normal peripheral blood mononuclear cells stimulated with IL-2. Cloned LAK cells showed significant cytotoxicity against human erythroleukemia cell line K 562, promyelocytic leukemia cell line HL 60 and T-lymphoblastic leukemia cell line Jurkat in standard 4-hr 51Cr release assay and the lytic percentage were 67.1%, 58.4% and 53.1% with E/T ratio of 40:1. Moreover, cloned LAK cells could also inhibit the 6-day spontaneous colony-formation of K 562 and HL 6 C cells in semisolid cultures when the LAK cells were preincubated with target cells for 4 hours in liquid medium at 37 degrees C. The degree of colony inhibition was 91% for K 562 and 96% for HL 60, which was quantitatively greater than that determined by 51Cr release at the same E/T ratio of 40:1. In addition, with MTT assay, cytotoxicity of supernatant of cloned LAK cells 3 days in culture against K 562 and HL 60 cells was observed. Our data indicated that cloned human LAK cells could kill both human leukemia cells and their stem cells and the mechanism may involve direct lysis and/or inhibition mediated by LAK cells and indirect inhibition of some soluble factors released from LAK cells.
authors.affiliation: Institute of Basic Medical Sciences, Beijing.
authors.forename: C Y
authors.initials: CY
authors.lastname: Jiang
mesh_terms: D002999:Clone Cells; D003602:Cytotoxicity, Immunologic; D006801:Humans; D015979:Killer Cells, Lymphokine-Activated / Q000502:physiology*; D004915:Leukemia, Erythroblastic, Acute / Q000473:pathology*; D015473:Leukemia, Promyelocytic, Acute / Q000473:pathology; D015458:Leukemia, T-Cell / Q000473:pathology; D014407:Tumor Cells, Cultured