CD34(+) hematopoietic stem cells exert accessory function in lipopolysaccharide-induced T cell stimulation and CD80 expression on monocytes.
CD34(+) hematopoietic stem cells, which circulate in peripheral blood with very low frequency, exert essential accessory function during lipopolysaccharide (LPS)-induced human T lymphocyte activation, resulting in interferon gamma production and proliferation. In contrast, stimulation of T cells by "conventional" recall antigens is not controlled by blood stem cells. These conclusions are based on the observation that depletion of CD34(+) blood stem cells results in a loss of LPS-induced T cell stimulation as well as reduced expression of CD80 antigen on monocytes. The addition of CD34-enriched blood stem cells resulted in a recovery of reactivity of T cells and monocytes to LPS. Blood stem cells could be replaced by the hematopoietic stem cell line KG-1a. These findings may be of relevance for high risk patients treated with stem cells or stem cell recruiting compounds and for patients suffering from endotoxin-mediated diseases.
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Department of Immunology and Cell Biology, Research Center Borstel, 23845 Borstel, Germany. ajulmer@fz-borstel.de
Girroleit
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Flad
H D
HD
Rietschel
E T
ET
Ulmer
A J
AJ
D000328:Adult; D000938:Antigen-Presenting Cells / Q000276:immunology*; D018952:Antigens, CD34 / Q000032:analysis; D018122:B7-1 Antigen / Q000096:biosynthesis*; D001773:Blood Cells / Q000276:immunology; D002460:Cell Line / Q000276:immunology; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000276:immunology; D006412:Hematopoietic Stem Cells / Q000276:immunology*; D006801:Humans; D018189:Immunomagnetic Separation; D007371:Interferon-gamma / Q000096:biosynthesis; D008070:Lipopolysaccharides / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology*; D008211:Lymphocyte Cooperation; D009000:Monocytes / Q000187:drug effects* / Q000378:metabolism; D016176:T-Lymphocyte Subsets / Q000187:drug effects / Q000276:immunology*; D014373:Tuberculin / Q000276:immunology