IgG vs IgE: mediators of antigen-induced guinea pig lung parenchymal contraction.
The present studies were conducted to determine whether different mediators are responsible for antigen-induced contraction of guinea pig lung parenchymal strips sensitized with either IgG or IgE. Passive sensitization was employed using IgG- or IgE-type antibody to ovalbumin which had been separated using Protein A-Sepharose as previously described (Regal, 1984a). Such a system ensures the presence of only one type of cytophilic antibody to mediate antigen-induced contraction of the isolated lung parenchymal strip. Pyrilamine, an H1 antagonist, caused a very slight delay in the onset of the antigen-induced contractions in both IgG- and IgE-sensitized strips, suggesting a very minor role for endogenous histamine in both systems. A combination of the leukotriene antagonist, FPL 55712, and pyrilamine caused a significant reduction in the antigen-induced contraction in IgG- but not IgE-sensitized lung parenchymal strips. Histamine release was detected on antigen challenge of both IgG- and IgE-sensitized lung. Using bioassay techniques, leukotriene release was primarily detected from IgG-sensitized lung and only minimally from IgE-sensitized lung. Thus, our studies have demonstrated a differential antagonism of IgG- and IgE-mediated airway contraction and suggest that leukotrienes are important mediators of antigen-induced lung parenchymal contraction in IgG- but not IgE-sensitized tissues.
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Regal
D000818:Animals; D000941:Antigens / Q000494:pharmacology; D001285:Atropine / Q000494:pharmacology; D002867:Chromones / Q000494:pharmacology; D006168:Guinea Pigs; D006636:Histamine Release; D007073:Immunoglobulin E / Q000502:physiology*; D007074:Immunoglobulin G / Q000502:physiology*; D007213:Indomethacin / Q000494:pharmacology; D008168:Lung; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D011738:Pyrilamine / Q000494:pharmacology; D013189:SRS-A / Q000378:metabolism
D000941:Antigens; D002867:Chromones; D007074:Immunoglobulin G; D013189:SRS-A; D007073:Immunoglobulin E; D001285:Atropine; C006312:FPL 55712; D011738:Pyrilamine; D007213:Indomethacin