FUNCTIONAL COMPETENCE OF DENDRITIC CELLS IN HUMAN UMBILICAL-CORD BLOOD

Dendritic cells (DC) are the main stimulators of primary T cell respon ses. Very little is known about DC in cord blood (CB), and whether the y are involved in the low incidence and severity of GVHD following CE: transplantation. Here, CBDC were identified as a HLA-DR+/lineage mark er (lin; CD3, CD11b. CD14, CD16, CD19, CD34, CD56 and glycophorin A an tigens) negative population, representing 0.3 +/- 0.1% (mean +/- s.d.; n = 15) of CB mononuclear cells, CBDC expressed the CD4, CD11a, CD18, CD45RA, CD50 and CD54 antigens but revealed no expression of the CD1a , CD11c, CD40, CD45RO,CD58, CD83, CD86 and CD102 antigens, Immunomagne tically enriched CBDC showed potent allostimulatory activity for CB T cells. Thus, CBDC are functionally competent and resemble in their imm ature/resting state CD11c(-) DC in peripheral blood.