IN-VITRO DIFFERENTIATION OF CD34(-POSITIVE LANGERHANS CELL AND THE INTERDIGITATING DENDRITIC CELL-TYPE() HEMATOPOIETIC PROGENITOR CELLS TOWARD DISTINCT DENDRITIC CELL SUBSETS OF THE BIRBECK GRANULE AND MIIC)

We have demonstrated recently that Birbeck granule-positive Langerhans cells (LC) can be derived from CD34(+) peripheral blood progenitor ce lls in the presence of a seven-cytokine cocktail (CC7-7). Here, we sho w that the sequential use of early-acting hematopoietic growth factors , stem cell factor, interleukin (IL)-3, and IL-6, followed on day 8 by differentiation in the two-factor combination IL-4 plus granulocyte-m acrophage colony-stimulating factor (GM-CSF) (CC4GM) is more efficient and allows the cells to be arrested in the LC stage for more than 1 w eek while continuous maturation occurs in CC7-7. Maturation of LC to i nterdigitating dendritic cells (DC) could specifically be induced with in 60 hours by addition of tumor necrosis factor-alpha (20 ng/mL) or l ipopolysaccharide (100 ng/mL). Using LC that had been enriched to grea ter than 90% CD1a(+) cells by an immunoaffinity column, we were able t o define clear-cut differences between LC and DC that corroborate data of the respective cells derived from epithelial borders (LC) or from lymph nodes (LN) and spleen (DC). Thus, molecules and functions involv ed in antigen (AG) uptake and processing were highly expressed in LC, while those involved in AG presentation were at maximum in DC. LC were CD1a(++) DR(++). CD23(+), CD36(+), CD80(-), CD86(-), and CD25(-), whi le DC were CD1a(+/-) DR(+++), CD23(-), CD36(-), CD80(+), CD86(++), and CD25(+). CD40 and CD32 were moderately expressed and nearly unchanged on maturation, in contrast to monocyte-derived DC. Macropinocytosis o f fluorescein isothiocyanate-dextran was dominant in LC, as were multi lamellar major histocompatibility complex (MHC) class II compartments (MIICs). which were detected by electron microscopy. The functional di chotomy of these cell types was finally supported by testing the AG-pr esenting cell function for tetanus toroid to primed autologous T-cell lines, which was optimal when cells were loaded with AG as LC and subs equently induced to become DC. (C) 1996 by The American Society of Hem atology.