A soluble form of CD83 is released from activated dendritic cells and B lymphocytes, and is detectable in normal human sera.
CD83 is an inducible glycoprotein expressed predominantly by dendritic cells (DC) and B lymphocytes. Expression of membrane CD83 (mCD83) is widely used as a marker of differentiated/activated DC but its function and ligand(s) are presently unknown. We report the existence of a soluble form of CD83 (sCD83). Using both a sCD83-specific ELISA and Western blotting, we could demonstrate the release of sCD83 by mCD83(+) B cell and Hodgkin's disease-derived cell lines, but not mCD83(-) cells. Inhibition of de novo protein synthesis did not affect the release of sCD83 during short-term (2 h) culture of cell lines although mCD83 expression was significantly reduced, suggesting sCD83 is generated by the release of mCD83. Isolated tonsillar B lymphocytes and monocyte-derived DC, which are mCD83(low), released only low levels of sCD83 during culture. However, the differentiation/activation of these populations both up-regulated mCD83 and increased sCD83 release significantly. Analysis of sera from normal donors demonstrated the presence of low levels (121 +/- 3.6 pg/ml) of circulating sCD83. Further studies utilizing purified sCD83 and the analysis of sCD83 levels in disease may provide clues to the function and ligand(s) of CD83.
Hock
B D
BD
Haematology/Immunology Research Group, Christchurch Hospital and Christchurch School of Medicine, Christchurch, New Zealand.
Kato
M
M
McKenzie
J L
JL
Hart
D N
DN
D015703:Antigens, CD; D001402:B-Lymphocytes / Q000276:immunology*; D015415:Biomarkers; D002461:Cell Line, Transformed; D003713:Dendritic Cells / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006801:Humans; D007136:Immunoglobulins / Q000097:blood* / Q000378:metabolism; D019169:Jurkat Cells; D008213:Lymphocyte Activation / Q000276:immunology; D008562:Membrane Glycoproteins / Q000097:blood* / Q000378:metabolism; D012995:Solubility; D020298:U937 Cells; D000097802:CD83 Antigen
D015703:Antigens, CD; D015415:Biomarkers; D007136:Immunoglobulins; D008562:Membrane Glycoproteins; D000097802:CD83 Antigen