TNF-alpha is secreted by monocytes in transit to become macrophages, but not by peripheral blood monocytes, following OK-432 (lyophilized S. pyogenes) stimulation.
OK-432, penicillin-killed Streptococcus pyogenes, is used in treating lymphangiomas and carcinomas. We have studied proinflammatory interleukin (IL) secretion following OK-432 stimulation of total blood, peripheral blood mononuclear cell (PBMC) and purified monocytes in vitro. OK-432 stimulation of purified monocytes gave IL-1beta, IL-1RA, IL-6, IL-12p40 and tumour necrosis factor (TNF)-alpha response. OK-432 stimulation of cells within blood did, however, not yield TNF-alpha secretion. When PBMC or monocytes were cultured in low-attachment wells a decreased IL secretion was observed compared to adherent cells. Inhibition of Syk kinase with piceatannol, only at high, non-specific doses, but not PI3 kinase inhibition with LY294002 or Wortmannin, decreased monocyte IL response to OK-432. This shows that beta(1-3)-integrin receptor function is not necessary for monocyte OK-432-stimulated TNF-alpha secretion. Direct blockage of the beta(2)-integrin (CD18) receptor by anti-CD18 antibody was also unable to prevent the stimulating effects of OK-432 in human monocytes. On the other hand, Syk phosphorylation is elevated upon adherence of monocytes and this is further increased by OK-432 stimulation, as shown by Western blot. The Fc-receptor was also ruled out as a main receptor of the OK-432 monocyte response. In conclusion, TNF-alpha secretion is only found in monocytes removed from blood. This TNF-alpha secretion is not mediated through the beta(1-3)-integrin receptors. OK-432 may act as a target-seeking substance whereby only monocytes adhered, e.g. to a tumour cell, become cytotoxic in part explaining why OK-432 is well suited as a cancer treatment drug.
Olsnes
C
C
Department of Surgical Sciences, Haukeland University Hospital, Bergen, Norway. carla.olsnes@ore.uib.no
Stavang
H
H
Olofsson
J
J
Aarstad
H J
HJ
D000328:Adult; D002448:Cell Adhesion / Q000276:immunology; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D004791:Enzyme Inhibitors; D006258:Head and Neck Neoplasms / Q000097:blood* / Q000188:drug therapy / Q000473:pathology; D006801:Humans; D007111:Immunity, Cellular / Q000187:drug effects; D007371:Interferon-gamma / Q000276:immunology; D007378:Interleukins / Q000276:immunology; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000276:immunology; D008070:Lipopolysaccharides / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects; D008264:Macrophages / Q000166:cytology / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D010844:Picibanil / Q000008:administration & dosage* / Q000097:blood / Q000737:chemistry; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D012016:Reference Values; D000072377:Syk Kinase; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
D004791:Enzyme Inhibitors; D007378:Interleukins; D047908:Intracellular Signaling Peptides and Proteins; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D010844:Picibanil; D007371:Interferon-gamma; D011505:Protein-Tyrosine Kinases; C000606896:SYK protein, human; D000072377:Syk Kinase