title: Contribution of anaphylatoxin C5a to late airway responses after repeated exposure of antigen to allergic rats.
abstract: We attempted to elucidate the contribution of complement to allergic asthma. Rat sensitized to OVA received repeated intratracheal exposures to OVA for up to 3 consecutive days, and pulmonary resistance was then estimated for up to 6 h after the last exposure. Whereas the immediate airway response (IAR) in terms of R(L) tended to decrease in proportion to the number of OVA exposures, late airway response (LAR) became prominent only after three. Although premedication with two kinds of complement inhibitors, soluble complement receptor type 1 (sCR1) or nafamostat mesylate, resulted in inhibition of the IAR after either a single or a double exposure, the LAR was inhibited after the triple. Premedication with a C5a receptor antagonist (C5aRA) before every exposure to OVA also inhibited the LAR after three. Repeated OVA exposure resulted in eosinophil and neutrophil infiltration into the bronchial submucosa which was suppressed by premedication with sCR1 or C5aRA. Up-regulation of C5aR mRNA was shown in lungs after triple OVA exposure, but almost no up-regulation of C3aR. Pretreatment with sCR1 or C5aRA suppressed the up-regulation of C5aR expression as well as cytokine messages in the lungs. The suppression of LAR by pretreatment with sCR1 was reversed by intratracheal instillation of rat C5a desArg the action of which was inhibited by C5aRA. In contrast, rat C3a desArg or cytokine-induced neutrophil chemoattractant-1 induced cellular infiltration into the bronchial submucosa by costimulation with OVA, but these had no influence on the LAR. These differences might be explained by the fact that costimulation with OVA and C5a synergistically potentiated IAR, whereas that with OVA and either C3a or cytokine-induced neutrophil chemoattractant-1 did not. C5a generated by Ag-Ab complexes helps in the production of cytokines and contributes to the LAR after repeated exposure to Ag.
authors.affiliation: Department of Pharmacology, School of Medicine, Fukuoka University, Fukuoka, Japan. abemasa@fukuoka-u.ac.jp
authors.forename: M
authors.initials: M
authors.lastname: Abe
authors.forename: K
authors.initials: K
authors.lastname: Shibata
authors.forename: H
authors.initials: H
authors.lastname: Akatsu
authors.forename: N
authors.initials: N
authors.lastname: Shimizu
authors.forename: N
authors.initials: N
authors.lastname: Sakata
authors.forename: T
authors.initials: T
authors.lastname: Katsuragi
authors.forename: H
authors.initials: H
authors.lastname: Okada
mesh_terms: D000403:Airway Resistance; D000818:Animals; D000941:Antigens / Q000008:administration & dosage / Q000276:immunology; D015703:Antigens, CD / Q000235:genetics / Q000302:isolation & purification; D001249:Asthma / Q000188:drug therapy / Q000209:etiology / Q000276:immunology*; D001550:Benzamidines; D001980:Bronchi / Q000473:pathology; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D054413:Chemokine CCL11; D019742:Chemokines, CC; D019743:Chemokines, CXC; D002630:Chemotactic Factors; D015926:Complement C3a / Q000031:analogs & derivatives* / Q000494:pharmacology; D015936:Complement C5a / Q000276:immunology*; D015937:Complement C5a, des-Arginine / Q000494:pharmacology; D016207:Cytokines / Q000235:genetics / Q000302:isolation & purification; D006133:Growth Substances; D006146:Guanidines / Q000627:therapeutic use; D006967:Hypersensitivity / Q000188:drug therapy / Q000209:etiology / Q000276:immunology*; D036341:Intercellular Signaling Peptides and Proteins; D008168:Lung / Q000276:immunology; D008565:Membrane Proteins; D010047:Ovalbumin / Q000008:administration & dosage / Q000276:immunology; D012333:RNA, Messenger / Q000302:isolation & purification; D051381:Rats; D044087:Receptor, Anaphylatoxin C5a; D011951:Receptors, Complement / Q000235:genetics / Q000302:isolation & purification; D017463:Receptors, Complement 3b / Q000627:therapeutic use
chemical_list: D000941:Antigens; D015703:Antigens, CD; D001550:Benzamidines; C515458:Ccl11 protein, rat; D054413:Chemokine CCL11; D019742:Chemokines, CC; D019743:Chemokines, CXC; D002630:Chemotactic Factors; D015937:Complement C5a, des-Arginine; D016207:Cytokines; D006133:Growth Substances; D006146:Guanidines; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D012333:RNA, Messenger; D044087:Receptor, Anaphylatoxin C5a; D011951:Receptors, Complement; D017463:Receptors, Complement 3b; C085567:complement C3a receptor; C044541:complement C3a, des-Arg-(77)-; D015926:Complement C3a; D015936:Complement C5a; D010047:Ovalbumin; C032855:nafamostat