LFA-1 (CD11a/CD18) triggers hydrogen peroxide production by canine neutrophils.
The respiratory burst of neutrophils stimulated by chemotactic factors is markedly augmented by Mac-1-dependent adhesion such as the interaction of Mac-1 (CD11b/CD18) with intercellular adhesion molecule-1 (ICAM-1; CD54) expressed on the surface of parenchymal cells (e.g., cardiac myocytes). In the current study, we evaluate the hypothesis that lymphocyte function-associated antigen-1 (LFA-1; CD11a/CD18) can also trigger the respiratory burst in neutrophils. To isolate LFA-1/ICAM-1 interactions from Mac-1/ ICAM-1 interactions, full-length chimeric ICAM-1 was developed and expressed in L cells with domains 1 and 2 from canine ICAM-1 and domains 3-5 from human ICAM-1 (C1,2;H3-5). We have shown that canine neutrophils do not bind to human ICAM-1. We demonstrated that chimeric ICAM-1 C1,2;H3-5 supported only LFA-1-dependent adhesion of canine neutrophils and that such adhesion triggered rapid onset of H2O2 production from canine neutrophils. The following seven experimental conditions distinguished LFA-1-dependent H2O2 production from Mac-1-dependent production: It did not require exogenous chemotactic stimulation; H2O2 release was more rapid, but the amount released was <40% of that mediated by Mac-1 adhesion; it was inhibited by anti-CD11a and anti-ICAM-1 antibodies; in contrast to that mediated by Mac-1, it was not inhibited by anti-CD11b antibody, neutrophil inhibitory factor (NIF), or cytochalasin B or H7. Thus, canine neutrophils seem to be able to utilize two members of the beta2 integrin family to interact with ICAM-1 and signal H2O2 production, with LFA-1 at an early stage without prior chemotactic stimulation and Mac-1 at a later stage requiring chemotactic stimulation.
Department of Microbiology and Immunology, Baylor College of Medicine, Houston, Texas, USA.
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D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000494:pharmacology; D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects; D002478:Cells, Cultured; D004285:Dogs; D004730:Endothelium, Vascular / Q000166:cytology; D006023:Glycoproteins / Q000494:pharmacology; D015801:Helminth Proteins / Q000494:pharmacology; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism*; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics / Q000502:physiology*; D007739:L Cells; D016169:Lymphocyte Function-Associated Antigen-1 / Q000502:physiology*; D046911:Macromolecular Substances; D016177:Macrophage-1 Antigen / Q000502:physiology; D008565:Membrane Proteins; D051379:Mice; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000494:pharmacology / Q000502:physiology; D016897:Respiratory Burst / Q000187:drug effects*; D014162:Transfection
D000911:Antibodies, Monoclonal; D006023:Glycoproteins; D015801:Helminth Proteins; D016169:Lymphocyte Function-Associated Antigen-1; D046911:Macromolecular Substances; D016177:Macrophage-1 Antigen; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; D018799:Intercellular Adhesion Molecule-1; C086581:NIF protein, Ancylostoma caninum; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D006861:Hydrogen Peroxide