Effect of rhCDD (50 ng/plate) on colony formation of mouse BMC as a function of thymidine concentration added. The cells were cultured in a GM-CFC methylcellulose assay with 5 ng/mL of recombinant mouse IL-1β, IL-3, and stem cell factor as stimulators. Colonies of more than 50 cells were counted after 7 days. Mean values ± SD are given as percent of controls.