Il3 and Thpo expand hematopoietic progenitor cells. (A) Recombinant mouse Il3 was added to AGM explant cultures at the indicated concentrations. Three days later, cells were plated in methylcellulose, and total colonies were counted after 7 days. n = 3. (B) Total colonies separated into the different colony types. (C) Average number of total AGM cells obtained after 3 days of explant culture in the presence or absence of Il3. (D) Recombinant mouse Thpo was added to AGM explant cultures at the indicated concentrations. Three days later, cells were plated in methylcellulose, and total colonies were counted after 7 days. n = 3. (E) Total colonies separated into the different colony types. (F) Average number of total AGM cells obtained after 3 days of explant culture in the presence or absence of Thpo. (G) Recombinant mouse Epo was added to AGM explant cultures at the indicated concentrations. Three days later, cells were plated in methylcellulose, and total colonies were counted after 7 days. n = 3. (H) Total colonies separated into the different colony types. (I) Recombinant mouse Il2 or Il6 was added to AGM explant cultures at 100 ng/mL. Three days later, cells were plated in methylcellulose, and total colonies were counted after 7 days. n = 3.