title: CD8+ natural killer cells have a potential of a sensitive and reliable biodosimetric marker in vitro.
abstract: The aim of our work was to evaluate peripheral blood lymphocyte subsets as in vitro indicators of the received dose of ionizing radiation (biodosimetric markers) in the range of 3-20 Gy and to determine the appropriate time interval, during which a dose-dependent induction of apoptosis occurs upon gamma irradiation. In lymphocyte subsets characterized by double color surface immunophenotyping, four-color flow cytometry was used for visualizing cell death-associated increase in superficial phosphatidylserine exposure and cytoplasmic membrane permeability by fluorinated Annexin V and propidium iodide, respectively. No differences between sham-treated and lethal dose (7 Gy)-irradiated samples were observed upon 6 h cultivation in vitro. Ten and 18 h later, about 50 % of lymphocytes were apoptotic, but only the minority of them was in the late apoptotic phase. The only difference in radioresistance of the CD4(+)CD8(-) and CD4(-)CD8(+) lymphocyte subsets was seen upon 2-day cultivation when huge depletion of intact cells and prevalence of the late apoptotic population became obvious. A dose-dependence study in 16 and 48 h cultures confirmed the effectiveness of major T cell subsets as biodosimetric indicators. On the other hand, the minor CD8(+) subset of natural killer (NK) cells has been identified as a radiosensitive lymphocyte population the disappearance of which correlated with the received dose. We demonstrated that the CD3(-)CD8(+)NK subset can be used as a lethal/sublethal dose discriminator to 16 h cultivation. In addition, our data indicate that two-day cultivation followed by CD3/CD8 expression analysis in an intact lymphocyte population may provide a clue for low dosage biodosimetry.
authors.affiliation: Institute of Clinical Immunology and Allergology, Charles University in Prague Faculty ofMedicine in Hradec Králové, University Hospital.
authors.forename: D
authors.initials: D
authors.lastname: Vokurková
authors.forename: J
authors.initials: J
authors.lastname: Sinkora
authors.forename: J
authors.initials: J
authors.lastname: Vávrová
authors.forename: M
authors.initials: M
authors.lastname: Rezácová
authors.forename: J
authors.initials: J
authors.lastname: Knízek
authors.forename: J
authors.initials: J
authors.lastname: Ostereicher
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D015415:Biomarkers; D017252:CD3 Complex / Q000032:analysis; D015704:CD4 Antigens / Q000032:analysis; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000528:radiation effects*; D016827:CD8 Antigens / Q000032:analysis; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000528:radiation effects*; D002478:Cells, Cultured; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D006801:Humans; D016130:Immunophenotyping; D007694:Killer Cells, Natural / Q000276:immunology / Q000528:radiation effects*; D011836:Radiation Tolerance; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D015415:Biomarkers; D017252:CD3 Complex; D015704:CD4 Antigens; D016827:CD8 Antigens