Growth and differentiation kinetics of NK cells and DCs derived from CD34⁺CD33^lo thymocytes. (A) CD34⁺CD33^lo thymocytes (10⁵/well) were cultured during 9 days in 0.2 mL of medium supplemented with the mixture of IL-7, IL-1α, IL-6, SCF, and GM-CSF either without IL-2 (•) or with IL-2 (▪). An additional culture was set up without IL-2, and IL-2 was added at day 4 (▴). The number of total viable cells recovered at the indicated days was determined by trypan blue dye exclusion. (B) CD34⁺CD33^lo thymocyte cultures set up as described in (A) were analyzed by flow cytometry for the correlated expression of either CD7, CD13, and CD56, or CD7, CD13, and CD1, at the indicated days. The data show the absolute numbers of CD7⁺CD13^lo/−CD56⁺ NK cells (open symbols) and CD7^lo/−CD13⁺CD56⁻ DCs (solid symbols) recovered from cultures lacking IL-2 (•, ○) or supplemented with IL-2 either from day 0 (▪, □) or from day 4 (▴, ▵).