LDA of EPLM from Flt3L-treated mice. The figure summarizes the LDA for myeloid (□), T cell (⋄), and B cell (○) among EPLM from Flt3L-treated mice. Shown are the semilogarithmic plots of cell dose (horizontal linear scale) versus the percent negative cultures (vertical logarithmic scale) of 48 replicate cultures containing on average 2.5, 5, 10, or 20 sorted EPLM plated in 96-well microtiter plates containing irradiated ST2 stroma plus Flt3L for myeloid, OP9 plus IL-7 and Flt3L for B, or OP9-DL1 stroma plus IL-7 and Flt-3L for T cells. After 10 to 14 days, wells were scored for growth by microscopic examination. When 37% of replicate cultures are negative (horizontal line), according to Poisson statistics, each well would on average contain one precursor.