CD34(-BLOOD PROGENITOR-CELL AND MONOCYTE-DERIVED DENDRITIC CELLS - A COMPARATIVE-ANALYSIS() PERIPHERAL)

Dendritic cells (DC) have been generated in vitro from either CD34(+) haemopoietic progenitor cells (HPC) or peripheral blood monocytes (Mo) in the presence of specific cytokine combinations, including granule cyte-macrophage colony-stimulating factor (GM-CSF). Since differences between DC from either source may be important for the clinical use of these antigen-presenting cells (APC)I a comparative analysis was perf ormed, HPC were expanded in the presence of interleukin (IL)-3, IL-6 a nd stem cell factor (SCF) (days 1-7) and subsequently induced by IL-4 + GM-CSF (days 8-26) to differentiate to Langerhans-type cells (pLC). The latter cytokines were similarly used to generate Mo-derived LC (mL C), Maturation of both cell types, pLC and mLC, to interdigitating DC- type cells (iDC) was induced by tumour necrosis factor-alpha (TNF-alph a) or lipopolysaccharide (LPS). Analysis of mLC/pLC and miDC/piDC with respect to morphology, phenotype, antigen uptake and presentation rev ealed a high similarity of DC from either source. The majority of mLC, however, exhibited a more mature differentiation stage, compared to p LC, evidenced from lower numbers of multilaminar MHC class II compartm ents and less efficient APC function for extracellular protein antigen s. Although macropinocytosis was performed by LC, neither LC nor iDC f rom either source were able to take up greater than or equal to 0.5 mu m latex beads. However, phagocytosis of 0.5 mu m and 1 mu m beads was performed by Mo that could subsequently be induced to become iDC, thu s providing the unique opportunity to present phagocytosed material in DC-type fashion. Mo may be the preferential source for clinical use o f iDC-type cells since preparation and culture are easier to perform a nd are less costly while APC function is similar to HPC-derived iDC.