Cells generated in the presence of TGF-β1 form large cell clusters and express the Birbeck granule antigen Lag.

Purified CD34⁺ cells were cultured for 12 to 14 days in serum-free medium supplemented with the cytokines GM-CSF plus TNFα, SCF, and FL in the presence or absence of TGF-β1. Day 12–generated cells were harvested and analyzed by phase-contrast microscopy (original magnification, ×20) and flow cytometry. Diagrams show expression of the intracellular Birbeck granule–associated molecule Lag versus orthogonal light scatter (SSC) of cells generated in the presence or absence of TGF-β1, as indicated. Markers were set according to negative control staining.