Correlated expression of CD1a and LZ by cells generated in the presence or absence of FL and/or TGF-β1. Purified CD34⁺ CB cells were cultured for 10 days in serum-free medium in the presence of the basic growth factor combination GM-CSF plus TNFα and SCF. Parallel cultures were further supplemented with TGF-β1 and/or FL at culture initiation (see the Materials and Methods). Day-10 cells were harvested and combined stained for intracellular LZ and surface-membrane CD1a expression (see the Materials and Methods). Representative diagrams show LZ (x-axis) versus CD1a (y-axis) expression by cells generated in the absence or presence of TGF-β1 and/or FL as indicated. Markers were set according to negative control stainings (see the Materials and Methods). Histograms shown in the lower part are cells obtained from identical culture conditions as described above that were submitted to indirect staining for the BG-associated molecule Lag (as described in the Materials and Methods). Overlay histograms represent Lag stainings of cells generated in TGF-β1 nonsupplemented (faint lines) and TGF-β1 supplemented (bold lines) cultures. Cultures without (left overlay histograms) or with FL supplementation (right overlay histograms) are shown. Flow cytometric analyses show at least 5,000 cells.