MOLECULAR AND FUNCTIONAL-CHARACTERISTICS OF DENDRITIC CELLS GENERATEDFROM HIGHLY PURIFIED CD14(-BLOOD MONOCYTES() PERIPHERAL)

Dendritic cells (DC) ape the most potent APCs within the immune system . We show here that highly purified CD14(bright) peripheral blood mono cytes supplemented with granulocyte-monocyte (GM)-CSF plus IL-4 develo p with high efficacy (>95% of input cells) into DC. They neo-expressed CD1a, CD1b, CD1c, CD80, and CD5; they massively up-regulated CD40 (10 9-fold) and HLA-DQ and DP (125- and 87-fold); and significantly (>5-fo ld) up-regulated HLA-DR, CD4, CD11b, CD11c, CD43, CD45, CD45R0, CD54, CD58, and CD59. CD14, CD15s, CD64, and CDw65 molecules were down-regul ated to background levels, and no major changes were observed for HLA class I, CD11a, CD32, CD33, CD48, CD50, CD86, CDw92, CD93, or CD97. Mo nocytes cultured in parallel with GM-CSF plus TNF-alpha were more hete rogeneous in expression densities but otherwise similar in their surfa ce molecule repertoire. They clearly differed, however, in their acces sory cell capacity. Only GM-CSF plus IL-4-cultured cells were found to be potent stimulators in allogeneic and autologous MLR and they prese nted tetanus toroid 100- to 1000-fold more efficiently than other cell populations tested. Furthermore, only cytokine-treated monocytes form ed clusters with resting T cells. At variance from all these similarit ies between in vitro-generated monocyte-derived DC and in vivo-develop ing DC, the DC populations generated by res contained significant amou nts of myeloperoxidase and also expressed lysozyme. At least in this r espect they, thus, differ from ''classical'' DC types.