title: Heterologous desensitization of IL-8-mediated chemotaxis in human neutrophils by a cell-binding fragment of fibronectin.
abstract: In this study, we have explored the mechanism for the desensitization of IL-8-mediated neutrophil chemotaxis by a cell-binding fragment of fibronectin (120-kDa FN). Preincubation of neutrophil suspensions with the 120-kDa FN fragment resulted in a heterologous desensitization of IL-8-mediated chemotaxis while not affecting neutrophil chemotaxis to either fMLP or zymosan-activated serum. Preincubation of neutrophils with the beta1-integrin-activating antibody (TS2/16) mimicked the effects of the 120-kDa FN fragment while preincubating neutrophils with the beta1-integrin blocking antibody (mAb13) abrogated the inhibitory effects of the 120-kDa FN fragment on IL-8-mediated chemotaxis. Furthermore, we also demonstrated that the 120-kDa FN fragment did not inhibit chemotaxis to the CXC chemokine MGSA/GROalpha which interacts with high affinity to the IL-8 receptor B (CXCR2). By in vivo phosphorylation of neutrophils and probing lysates with an anti-CXCR1 antibody, we demonstrated that the addition of the cell-binding fragment of fibronectin resulted in a time-dependent phosphorylation of CXCR1. These findings suggest that the mechanism of heterologous desensitization of IL-8-mediated chemotaxis following ligation of FN-dependent integrins is the result of phosphorylation of the CXCR1 receptor.
authors: Department of Physiology and Cell Biology, Albany Medical College, New York 12208, USA.
authors: K J
authors: KJ
authors: Stanton
authors: M B
authors: MB
authors: Frewin
authors: P W
authors: PW
authors: Gudewicz
mesh_terms: D000906:Antibodies / Q000494:pharmacology; D015703:Antigens, CD / Q000737:chemistry / Q000378:metabolism; D002478:Cells, Cultured; D002634:Chemotaxis, Leukocyte / Q000276:immunology*; D004306:Dose-Response Relationship, Immunologic; D005353:Fibronectins / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D016023:Integrins / Q000276:immunology; D016209:Interleukin-8 / Q000037:antagonists & inhibitors / Q000276:immunology* / Q000378:metabolism; D009504:Neutrophils / Q000276:immunology* / Q000378:metabolism; D010446:Peptide Fragments / Q000502:physiology*; D010766:Phosphorylation; D019707:Receptors, Chemokine / Q000037:antagonists & inhibitors / Q000378:metabolism; D018123:Receptors, Interleukin / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D023062:Receptors, Interleukin-8A; D023063:Receptors, Interleukin-8B
chemical_list: D000906:Antibodies; D015703:Antigens, CD; D005353:Fibronectins; D016023:Integrins; D016209:Interleukin-8; D010446:Peptide Fragments; D019707:Receptors, Chemokine; D018123:Receptors, Interleukin; D023062:Receptors, Interleukin-8A; D023063:Receptors, Interleukin-8B