title: Hamycin inhibits IL-8-induced biologic response by modulating its receptor in human polymorphonuclear neutrophils.
abstract: IL-8, a neutrophil chemotactic agent, is involved in a large number of neutrophil-driven acute and chronic inflammatory diseases. We have found that hamycin, an antifungal agent, reduces IL-8-induced migration and binding of 125I-labeled IL-8 to neutrophils by 66 and 75%, respectively. Other IL-8-induced biologic functions, such as superoxide generation, intracellular Ca2+ mobilization, and enzyme release were also reduced in hamycin-treated cells by 50 to 75%. Anti-IL-8R Ab (C-X-CR1) and IL-8 itself failed to protect the cells from the effect of hamycin. Scatchard analysis of IL-8 binding data demonstrated that while the normal cells expressed 23,000 +/- 1,704 receptors/cell (Kd = 3.5 nM), the number was reduced to 8,000 +/- 592 receptors/cell (Kd = 3.43 nM) in hamycin-treated cells. Chemical cross-linking of 125I-labeled IL-8 to its receptor followed by 10% SDS-PAGE analysis and autoradiography showed that the signals in hamycin-treated cells were considerably reduced compared with those in controls. In the immunoblot, however, the signals in control and hamycin-treated cells were almost identical. The intensity of the fluorescence emission of diphenyl hexatriene at 430 nm and membrane microviscosity measured by diphenyl hexatriene were considerably reduced in hamycin-treated cells, resulting in a reduced number of functional IL-8R, presumably by conformational change in the receptor. The study suggests that hamycin may be a potent immunomodulator of the IL-8R for alleviation of inflammatory distress.
authors.affiliation: Division of Immunobiology, Indian Institute of Chemical Biology, Calcutta.
authors.forename: S K
authors.initials: SK
authors.lastname: Manna
authors.forename: S
authors.initials: S
authors.lastname: Samanta
authors.forename: A K
authors.initials: AK
authors.lastname: Samanta
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000935:Antifungal Agents / Q000494:pharmacology*; D015703:Antigens, CD / Q000097:blood / Q000187:drug effects*; D001345:Autoradiography; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000097:blood; D002470:Cell Survival / Q000187:drug effects; D002634:Chemotaxis, Leukocyte / Q000187:drug effects; D004161:Diphenylhexatriene / Q000031:analogs & derivatives; D004338:Drug Combinations; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000378:metabolism; D005456:Fluorescent Dyes; D005947:Glucose / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000097:blood; D015151:Immunoblotting; D016209:Interleukin-8 / Q000037:antagonists & inhibitors* / Q000097:blood / Q000494:pharmacology; D007457:Iodine Radioisotopes; D008024:Ligands; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D009580:Nitroblue Tetrazolium; D016011:Normal Distribution; D010101:Oxygen Consumption; D010743:Phospholipids / Q000494:pharmacology; D010972:Platelet Activating Factor / Q000494:pharmacology; D011090:Polyenes / Q000494:pharmacology; D011485:Protein Binding / Q000276:immunology; D018123:Receptors, Interleukin / Q000097:blood / Q000187:drug effects*; D023062:Receptors, Interleukin-8A; D013481:Superoxides / Q000097:blood; D014783:Viscosity
chemical_list: D000276:Adjuvants, Immunologic; D000935:Antifungal Agents; D015703:Antigens, CD; D004338:Drug Combinations; D005456:Fluorescent Dyes; D016209:Interleukin-8; D007457:Iodine Radioisotopes; D008024:Ligands; D010743:Phospholipids; D010972:Platelet Activating Factor; D011090:Polyenes; D018123:Receptors, Interleukin; D023062:Receptors, Interleukin-8A; D013481:Superoxides; C100114:hamycin; D004161:Diphenylhexatriene; D009580:Nitroblue Tetrazolium; D009240:N-Formylmethionine Leucyl-Phenylalanine; C037385:1-(4'-carboxyethyl)-6-diphenyl-1,3,5-hexatriene; D006861:Hydrogen Peroxide; D005947:Glucose; D002118:Calcium