B7/BB-1 is a leucocyte differentiation antigen on human dendritic cells induced by activation.
Activation of a primary T-lymphocyte response requires additional signals apart from interaction of the T-cell receptor (TcR)/CD3 complex with major histocompatibility complex (MHC) antigens on the antigen-presenting cell. The CD28 antigen on T lymphocytes provides an important co-stimulatory signal to T lymphocytes and we therefore searched for the presence of its ligand, the B7/BB-1 antigen, on blood and tonsil dendritic cells (DC). Blood DC, prepared from peripheral blood mononuclear cells with a minimal period of in vitro culture, did not stain with the monoclonal antibody BB-1 using flow cytometry analysis. In contrast, tonsil DC stained weakly for B7/BB-1 compared to positive control cell lines. Polymerase chain reaction (PCR) was used to amplify a 605 base pair (bp) fragment from human B7/BB-1 mRNA and demonstrated significant amounts of B7/BB-1 mRNA in tonsil DC but no specific product was obtained from blood DC, confirming the surface-staining results. Weak expression of B7/BB-1 antigen was detected by immunofluorescence analysis following culture of blood DC with either interferon-gamma (IFN-gamma) or granulocyte-macrophage colony-stimulating factor (GM-CSF). These data support the concept that blood DC give rise to tissue and/or lymphoid DC, which acquire co-stimulatory ligands as a result of activation and/or differentiation.
Hart
D N
DN
Haematology Department, Christchurch Hospital, New Zealand.
Starling
G C
GC
Calder
V L
VL
Fernando
N S
NS
D000911:Antibodies, Monoclonal / Q000276:immunology; D015703:Antigens, CD / Q000276:immunology*; D001483:Base Sequence; D003713:Dendritic Cells / Q000276:immunology*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000276:immunology; D006801:Humans; D007371:Interferon-gamma / Q000276:immunology; D008024:Ligands; D008213:Lymphocyte Activation; D008969:Molecular Sequence Data; D014066:Palatine Tonsil / Q000276:immunology; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D008024:Ligands; D012333:RNA, Messenger; D007371:Interferon-gamma; D016178:Granulocyte-Macrophage Colony-Stimulating Factor