Effect of Spi-B overexpression on T-cell development in an FTOC.

CD34⁺CD38⁻ fetal liver cells were transduced with LZRS Spi-B-IRES-GFP or with control-IRES-GFP and incubated with murine fetal lobes as indicated in “Materials and methods.” The lobes were seeded with 20 000 progenitor cells per lobe. (A) Expression of CD4, CD8, CD3, and CD56 of the Spi-B– and control-transduced cells. The quadrants were placed to include 99% of the cells stained with control antibodies. (B) Number of output cells per 1000 input progenitor cells. The transduction efficiencies were determined 3 days after the transduction. Based on the percentages of GFP⁺ cells in the samples, the numbers of input progenitor cells were calculated. The output numbers of each population were calculated on the basis of the total numbers of cells harvested from the FTOC, the percentages of transduced cells, and the percentages of each population.