title: A novel enhanced green fluorescent protein (EGFP)-K562 flow cytometric method for measuring natural killer (NK) cell cytotoxic activity.
abstract: Enhanced green fluorescent protein (EGFP) was stably expressed in human erythroleukaemia K562 cells (EGFP-K562) and used as target cells for measurement of natural killer (NK) cell cytotoxicity by flow cytometry. The compromised EGFP-K562 target cells were stained with propidium iodide (PI) and showed dual (green-red) fluorescent. Although the kinetic study demonstrated that the optimal incubation time for the assay was 4 h, a 2-h incubation period also gave comparable results. This new technique correlated strongly with the standard chromium (51Cr) release assay at the correlation coefficients of 0.87 and 0.89 at p-value <0.001 for 2- and 4-h incubation times, respectively. The EGFP-K562 stable cell line provides a novel method to measure NK cytotoxicity by flow cytometry without pre-staining or pre-labeling target cells.
authors.affiliation: Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand. siwkk@mahidol.ac.th
authors.forename: Wannee
authors.initials: W
authors.lastname: Kantakamalakul
authors.forename: Jiraporn
authors.initials: J
authors.lastname: Jaroenpool
authors.forename: Kovit
authors.initials: K
authors.lastname: Pattanapanyasat
mesh_terms: D000328:Adult; D002857:Chromium; D004396:Coloring Agents; D003601:Cytotoxicity Tests, Immunologic / Q000379:methods*; D005260:Female; D005434:Flow Cytometry / Q000379:methods*; D049452:Green Fluorescent Proteins; D006801:Humans; D066298:In Vitro Techniques; D020014:K562 Cells; D007694:Killer Cells, Natural / Q000276:immunology*; D007700:Kinetics; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism*; D008297:Male; D011419:Propidium; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D004396:Coloring Agents; D008164:Luminescent Proteins; D011994:Recombinant Proteins; D002857:Chromium; D049452:Green Fluorescent Proteins; D011419:Propidium