title: Enhancement of antigen-induced bronchoconstriction in the guinea pig after intravascular complement activation with cobra venom factor.
abstract: The purpose of the present studies was to begin to test the hypothesis that the complement system is important for antigen-induced bronchoconstriction in the guinea pig. The effect of the complement-depleting agent cobra venom factor (CVF) on antigen-induced bronchoconstriction in guinea pigs passively sensitized with IgG or IgE antibody to ovalbumin was determined. Intravenous injection of CVF significantly reduced total hemolytic complement activity (CH50), caused a transient decrease in dynamic lung compliance, an increase in pulmonary resistance, and a decrease in circulating white blood cells with a sustained decrease in platelets. Antigen-induced bronchoconstriction was not inhibited in either IgG- or IgE-sensitized guinea pigs depleted of complement. Thus, a role for the complement system as a contributing factor in antigen-induced bronchoconstriction was not supported. On the contrary, our studies revealed an enhanced antigen-induced bronchoconstriction in guinea pigs depleted of complement with CVF. Our studies were then directed towards characterizing the enhanced response to begin to determine the mechanism responsible. The enhanced antigen-induced bronchoconstriction occurred in both IgG- and IgE-sensitized guinea pigs and was most apparent at lower antigen doses. The enhanced response still occurred in animals treated for 5 min with a dose of CVF (10 U) which caused no demonstrable decrease in CH50, a 30% level of conversion of C3, and a normal response to C5a. These data suggested that the enhanced response was not related to the level of C5a responsiveness of the animal.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Pharmacology, University of Minnesota-Duluth School of Medicine.
authors.forename: J F
authors.initials: JF
authors.lastname: Regal
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage* / Q000494:pharmacology; D000403:Airway Resistance / Q000187:drug effects; D000818:Animals; D000941:Antigens / Q000276:immunology*; D001986:Bronchial Spasm / Q000276:immunology*; D003167:Complement Activation; D004546:Elapid Venoms / Q000008:administration & dosage* / Q000494:pharmacology; D006168:Guinea Pigs; D007114:Immunization; D007275:Injections, Intravenous; D008170:Lung Compliance / Q000187:drug effects; D008297:Male
chemical_list: D000276:Adjuvants, Immunologic; D000941:Antigens; D004546:Elapid Venoms; C016310:cobra venom factor