Progression of leukemia after adoptive transfer of LICs. (A) Serial whole-animal luminescent imaging of a representative cohort of recipient mice performed at different times after animals received intravenous injections of 2 × 10⁵Arf^−/−p185⁺luc⁺ LICs. Each panel includes a control, disease-free mouse (at far left) imaged under identical experimental conditions. All images are scaled to a maximum intensity of 1 × 10⁶ photons (p)/s/cm²/sr. Rapid increases in bioluminescence signals were noted with disease progression. (B) Randomly selected mice at 3, 7, and 10 days (n = 4 in each group) and at 13 days (n = 10) after injection of luc⁺ LICs were euthanized, and determinations of white blood counts (WBC), spleen mass, and in vitro luminescence assays of bone marrow (BM) cell suspensions, expressed as relative light units, were performed. The dotted lines at the bottom of each graph represent the upper limits of normal WBC values (left) and spleen masses (middle) for age-matched male C57BL/6J mice, and the lower limit of sensitivity of the in vitro bone marrow cell luminescence assay (right). Median values are represented by solid horizontal lines and standard errors of the mean by brackets.