IP-10 Induces Eosinophil Superoxide Anion Generation

Abstract

RationaleRespiratory virus infection is the major cause of exacerbation of asthma. One of the host responses to viral infection is generation of CXC-chemokines including IP-10. Although the exact mechanisms of airway inflammation of asthma during acute exacerbation remain to be established, recent evidences suggests that IP-10, a ligand to CXCR3, may be involved. The objective of this study is to examine whether IP-10 induces eosinophil superoxide anion(O2-) generation.MethodsAdhesion proteins were dissolved in 0.05 M NaHCO3 coating buffer (15 mM NaHCO3, 35 mM Na2CO3, pH 9.2), added to 96-well plates and incubated at 4 oC overnight. Eosinophils were isolated from blood of healthy donors. O2- generation was examined based on the superoxide dismutase (SOD)-inhibitable reduction of ferricytochrome C.ResultsIP-10 by itself did not induce O2-generation from eosinophils. However, when eosinophils are inclubated in plates coated with rh-ICAM-1 and stimulated with IP-10, a significant generation of O2- was observed. The eosinophil O2-generation induced by a combination of rh-ICAM-1 and IP-10 was blocked by an anti-β2 integrin mAb. Similarly, eosinophil O2- generation by ICAM-1 plus IP-10 was blocked by anti-CXCR3 mAb.ConclusionsOur results suggest that IP-10 can induce eosinophil O2- generation in the presence of ICAM-1. Such activation of eosinophils induced by CXCR3 ligands, such as IP-10, may be a novel mechanism in the development of eosinophilic inflammation in the airway of asthma. RationaleRespiratory virus infection is the major cause of exacerbation of asthma. One of the host responses to viral infection is generation of CXC-chemokines including IP-10. Although the exact mechanisms of airway inflammation of asthma during acute exacerbation remain to be established, recent evidences suggests that IP-10, a ligand to CXCR3, may be involved. The objective of this study is to examine whether IP-10 induces eosinophil superoxide anion(O2-) generation. Respiratory virus infection is the major cause of exacerbation of asthma. One of the host responses to viral infection is generation of CXC-chemokines including IP-10. Although the exact mechanisms of airway inflammation of asthma during acute exacerbation remain to be established, recent evidences suggests that IP-10, a ligand to CXCR3, may be involved. The objective of this study is to examine whether IP-10 induces eosinophil superoxide anion(O2-) generation. MethodsAdhesion proteins were dissolved in 0.05 M NaHCO3 coating buffer (15 mM NaHCO3, 35 mM Na2CO3, pH 9.2), added to 96-well plates and incubated at 4 oC overnight. Eosinophils were isolated from blood of healthy donors. O2- generation was examined based on the superoxide dismutase (SOD)-inhibitable reduction of ferricytochrome C. Adhesion proteins were dissolved in 0.05 M NaHCO3 coating buffer (15 mM NaHCO3, 35 mM Na2CO3, pH 9.2), added to 96-well plates and incubated at 4 oC overnight. Eosinophils were isolated from blood of healthy donors. O2- generation was examined based on the superoxide dismutase (SOD)-inhibitable reduction of ferricytochrome C. ResultsIP-10 by itself did not induce O2-generation from eosinophils. However, when eosinophils are inclubated in plates coated with rh-ICAM-1 and stimulated with IP-10, a significant generation of O2- was observed. The eosinophil O2-generation induced by a combination of rh-ICAM-1 and IP-10 was blocked by an anti-β2 integrin mAb. Similarly, eosinophil O2- generation by ICAM-1 plus IP-10 was blocked by anti-CXCR3 mAb. IP-10 by itself did not induce O2-generation from eosinophils. However, when eosinophils are inclubated in plates coated with rh-ICAM-1 and stimulated with IP-10, a significant generation of O2- was observed. The eosinophil O2-generation induced by a combination of rh-ICAM-1 and IP-10 was blocked by an anti-β2 integrin mAb. Similarly, eosinophil O2- generation by ICAM-1 plus IP-10 was blocked by anti-CXCR3 mAb. ConclusionsOur results suggest that IP-10 can induce eosinophil O2- generation in the presence of ICAM-1. Such activation of eosinophils induced by CXCR3 ligands, such as IP-10, may be a novel mechanism in the development of eosinophilic inflammation in the airway of asthma. Our results suggest that IP-10 can induce eosinophil O2- generation in the presence of ICAM-1. Such activation of eosinophils induced by CXCR3 ligands, such as IP-10, may be a novel mechanism in the development of eosinophilic inflammation in the airway of asthma.