Qγ-H2AX, an analysis method for partial-body radiation exposure using γ-H2AX in non-human primate lymphocytes

We previously used the γ-H2AX assay as a biodosimeter for total-body irradiation (TBI) exposure (γ-rays) in a rhesus macaque (Macaca mulatta) model. Utilizing peripheral blood lymphocytes and plucked hairs, we obtained statistically significant γ-H2AX responses days after total-body exposure to 1-8.5 Gy (60Co γ-rays at 55 cGy min-1). Here, we introduce a partial-body exposure analysis method, Qγ-H2AX, which is based on the number of γ-H2AX foci per damaged cells as evident by having one or more γ-H2AX foci per cell. Results from the rhesus monkey - TBI study were used to establish Qγ-H2AX dose-response calibration curves to assess acute partial-body exposures. γ-H2AX foci were detected in plucked hairs for several days after in vivo irradiation demonstrating this assay's utility for dose assessment in various body regions. The quantitation of γ-H2AX may provide a robust biodosimeter for analyzing partial-body exposures to ionizing radiation in humans.