Identification of cord blood dendritic cells as an immature CD11c- population.
Dendritic cells (DC) are the main stimulators of primary T-cell responses and, thus, probably play a role in the immune reactions after stem cell transplantation. Very little is known about DC in cord blood (CB) and about their potential involvement in the low incidence and severity of acute graft-versus-host disease after CB transplantation. Here, CBDC were identified as a HLA-DR+ cell population, lacking the CD3, CD11b, CD14, CD16, CD19, CD34, CD56, and glycophorin A lineage markers (lin). This lin-/HLA-DR+ population represented 0.3% +/- 0.1% (mean +/- SD; range, 0.1% to 0. 6%; n = 15) of CB mononuclear cells, and CB contained 5.4 +/- 3.2 x 10(3) CBDC/mL (1.8 to 13.0 x 10(3); n = 15). CBDC expressed CD4, CD11a, CD18, CD45RA, CD50, CD54, and CD123, but showed no expression of CD1a, CD11c, CD33, CD40, CD45R0, CD80, CD83, and CD86 and only limited expression of CD58, CD102, and CD116. Despite this immature phenotype, immunomagnetically lin--enriched CBDC were potent stimulators of allogeneic CB T cells. As few as 266 +/- 107 (193 to 530; n = 10) lin-/HLA-DR+ CBDC stimulated a significant response. However, CBDC failed to take up protein or peptide antigens. Thus, in CB there is a prevalence of a DC subpopulation, resembling the CD11c- DC identified in tonsils, the so-called plasmacytoid T cells, which may exert a function distinct from the CD11c+ DC subpopulation.
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Bone Marrow Donor Center with Transplantation Immunology and EuroCord Bank Germany, Heinrich Heine University Medical Center, Düsseldorf, Germany.
Kögler
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Wernet
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D000595:Amino Acid Sequence; D017951:Antigen Presentation; D000943:Antigens, Differentiation / Q000032:analysis; D002454:Cell Differentiation; D019070:Cell Lineage; D003713:Dendritic Cells / Q000145:classification*; D005312:Fetal Blood / Q000166:cytology*; D006086:Graft vs Host Disease / Q000276:immunology; D006801:Humans; D018189:Immunomagnetic Separation; D016130:Immunophenotyping; D007231:Infant, Newborn; D016167:Integrin alphaXbeta2 / Q000032:analysis*; D008969:Molecular Sequence Data
D000943:Antigens, Differentiation; D016167:Integrin alphaXbeta2