title: Human blood dendritic cells exhibit a distinct T-cell-stimulating mechanism and differentiation pattern.
abstract: In this study, the mechanisms underlying stimulation of T-cell proliferation by human blood dendritic cells (BDC) and their differentiation have been defined with a panel of monoclonal antibodies (MoAbs). It was found that the MoAbs against LFA-1 (CD11a), CD11c, LFA-3 (CD58), ICAM-1 (CD54) or HLA-DR could significantly suppress T-cell proliferation in an allogeneic mixed lymphocyte reaction (P < 0.05), while being unable to inhibit clustering of BDC with T cells. Addition of anti-CD18 or CD45 MoAbs increased the size of clusters after 18 h of culture, but had no effect on the proliferation of T cells (P < 0.05). The suppressive effect of the MoAbs may be viewed not as an inhibition of contact between BDC and T cells, but rather as a blocking of co-stimulatory signals for T-cell activation, which are mediated by interaction of the adhesion molecules. After depleting the BDC preparations of monocytes, we used a double staining in FACS analysis to demonstrate that BDC do not express specific T (CD3), B (CD20 and CD21) and myeloid cell markers (CD11b, CD13 and CD14), but abundant class II antigens. This pattern remained unaltered after 8 days of culture in the presence of 100 U/ml GM-CSF, although a threefold increase of HLA-DQ and ICAM-1 molecules on the cultured cells was observed.
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D015703:Antigens, CD / Q000502:physiology; D000954:Antigens, Surface / Q000032:analysis; D018968:CD58 Antigens; D015815:Cell Adhesion Molecules / Q000502:physiology; D002454:Cell Differentiation; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000502:physiology*; D006801:Humans; D018799:Intercellular Adhesion Molecule-1; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D016169:Lymphocyte Function-Associated Antigen-1 / Q000502:physiology; D008562:Membrane Glycoproteins / Q000502:physiology; D010587:Phagocytosis; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000954:Antigens, Surface; D018968:CD58 Antigens; D015815:Cell Adhesion Molecules; D016169:Lymphocyte Function-Associated Antigen-1; D008562:Membrane Glycoproteins; D018799:Intercellular Adhesion Molecule-1