Human peripheral blood contains two distinct lineages of dendritic cells

Human peripheral blood contains two populations of dendritic cells (DC) but their developmental relationship has not been established. Freshly isolate d CD11c(-) DC possessed a lymphoid morphology, lacked myeloid markers but e xpressed lymphoid markers (CD4(+) CD10(+)) whilst the CD11c(+) DC were mono cytoid in appearance and expressed myeloid markers. Although both populatio ns were allostimulatory, only the CD11c(+) DC were able to take up antigen. Irrespective of the culture conditions the CD11c(-) cells developed into C D11c(-) CD13(-) CD33(-) CD4(+) CD1a(-) CD83(+/-) DC. In contrast, cultured CD11c(+) cells developed the phenotype CD11c(+) CD13(+) CD33(+/-) CD4(-) CD 1a(+) CD83(+) CD9(+). Only the CD11c(+) DC expressed macrophage colony-stim ulating factor (M-CSF) receptor and gave rise to CD14(+), esterase(+), phag ocytic macrophages when cultured in M-CSF. These data suggest that these tw o populations of DC represent distinct lineages of antigen-presenting DC.