CD34 Hematopoietic Progenitors From Human Cord Blood Differentiate Along Two Independent Dendritic Cell Pathways in Response to Granulocyte-Macrophage Colony-Stimulating Factor Plus Tumor Necrosis Factor a: II. Functional Analysis

In response to granulocyte-macrophage colony-stimulating mannose polymers. The high efficiency of antigen capture factor plus tumor necrosis factor a, cord blood CD34 hemaof CD14-derived cells is coregulated with the expression of topoietic progenitor cells differentiate along two unrelated nonspecific esterase activity, a tracer of lysosomial compartdendritic cell (DC) pathways: (1) the Langerhans cells (LCs), ment. In contrast, the CD1a population never expresses which are characterized by the expression of CD1a, Birbeck nonspecific esterase activity. The most striking difference is granules, the Lag antigen, and E cadherin; and (2) CD14 the unique capacity of CD14-derived DCs to induce naive B cell-derived DCs, characterized by the expression of CD1a, cells to differentiate into IgM-secreting cells, in response to CD9, CD68, CD2, and factor XIIIa (Caux et al, J Exp Med CD40 triggering and interleukin-2. Thus, although the two 184:695, 1996). The present study investigates the functions populations can allow T-cell priming, initiation of humoral of each population. Although the two populations are responses might be preferentially regulated by the CD14equally potent in stimulating naive CD45RA cord blood T derived DCs. Altogether, those results show that different cells through apparently identical mechanisms, each also pathways of DC development might exist in vivo: (1) the LC displays specific activities. In particular CD14-derived DCs type, which might be mainly involved in cellular immune show a potent and long-lasting (from day 8 to day 13) antiresponses, and (2) the CD14-derived DC related to dermal gen uptake activity (fluorescein isothiocyanate dextran or DCs or circulating blood DCs, which could be involved in peroxidase) that is about 10-fold higher than that of CD1a humoral immune responses. cells, which is restricted to the immature stage (day 6). The q 1997 by The American Society of Hematology. antigen capture is exclusively mediated by receptors for