Survival of progenitors of H2K-BCL-2 transgenic and wild-type mice after irradiation. (A) Plating of bone marrow from irradiated mice on AC-6 or AC11 stromal cells. Bone marrow was isolated immediately after irradiation, which was given in a single dose, and plated on preirradiated stroma cells. Plating efficiency of clonogenic cells was determined at day 8 by counting the colonies. Combined data from three experiments, each datapoint represents one irradiated mouse. (B) Radioprotection of CFU-S day 12. HSCs were sorted from bone marrow from H2K-BCL-2 transgenic and wild-type mice, aliquoted, exposed to a single dose of irradiation, and injected into lethally irradiated (9.5 Gy, split dose) C57BI/Ka mice, five mice per group. Spleen colonies were counted on day 12. Error bars indicate standard deviations for each group of five spleens. Combined data from three separate experiments, containing a total of seven datapoints for the transgenic, and six for the wild-type mice. Some of these datapoints overlap and cannot be distinguished in the figure.