Phorbol ester activation of phospholipase D in human monocytes but not peripheral blood lymphocytes.
Previous reports have shown that 12-0-tetradecanoylphorbol-13-acetate can activate phospholipase D in human peripheral blood mononuclear cells as measured by an enzyme-catalyzed transphosphatidylation reaction (phosphatidylethanol formation). In the present study, the mononuclear cells were fractionated by two procedures to identify the responsive cells. Contrary to earlier suggestions, the results indicate that phorbol ester does not stimulate phospholipase D activity in normal lymphocytes. Thus, phosphatidylethanol was not produced by T lymphocytes (isolated by sheep erythrocyte rosette formation) or by a mixture of T and B lymphocytes (isolated by centrifugal elutriation). Under the same conditions, phorbol ester was able to activate phospholipse D in fractions that contained predominately monocytes. Preliminary experiments have further shown that phorbol ester does not induce phospholipase D activity in human T cell leukemic lines (MOLT-3, CEM, JURKAT, PEER) but can do so in some, but not all, B cell lines that have been infected with Epstein-Barr virus.
Kinsky
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Division of Basic Sciences, National Jewish Center for Immunology and Respiratory Medicine, Denver, Colorado 80206.
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Benedict
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D001402:B-Lymphocytes / Q000201:enzymology; D002469:Cell Separation; D004789:Enzyme Activation / Q000187:drug effects; D000431:Ethanol / Q000494:pharmacology; D020404:Glycerophospholipids; D006801:Humans; D015458:Leukemia, T-Cell / Q000201:enzymology; D008214:Lymphocytes / Q000201:enzymology*; D009000:Monocytes / Q000201:enzymology*; D010712:Phosphatidic Acids / Q000097:blood; D010739:Phospholipase D / Q000097:blood*; D010740:Phospholipases / Q000097:blood*; D013601:T-Lymphocytes / Q000201:enzymology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D020404:Glycerophospholipids; D010712:Phosphatidic Acids; C051521:phosphatidylethanol; D000431:Ethanol; D010740:Phospholipases; D010739:Phospholipase D; D013755:Tetradecanoylphorbol Acetate