Different abilities of two types of Fc gamma receptor on guinea-pig macrophages to trigger the phosphatidylinositol turnover.
When exposed to hen ovalbumin (OA) complexes of IgG antibodies, guinea-pig macrophages were found to augment the phosphatidylinositol (PI) turnover. This response depended on the IgG isotype of antibodies used; OA complex of IgG2 antibody (OA gamma 2) triggered it about 3 times more effectively than did OA complex of IgG1 antibody (OA gamma 1). The inhibition experiments with monoclonal antibodies to Fc gamma 1/gamma 2R and Fc gamma 2R showed that Fc gamma 2R triggered activation of the PI turnover more intensively than did Fc gamma 1/gamma 2R. The same results were also obtained by the cross-linking of Fc gamma 2Rs or Fc gamma 1/gamma 2Rs by a combination of anti-mouse IgG F(ab')2 and anti-Fc gamma 2R F(ab')2 or anti-Fc gamma 1/gamma 2R F(ab')2. As the number of Fc gamma 2R molecules per macrophage is about one-half that of Fc gamma 1/gamma 2R molecules, the ability of Fc gamma 2R to trigger the response was found to be much greater than that of Fc gamma 1/gamma 2R. Despite this difference, neither the activity of Fc gamma 2R nor that of Fc gamma 1/gamma 2R to augment the PI turnover were affected by depletion of the intracellular Ca2+ by incubating the cells with Ionomycin and EGTA, and also by the treatment with pertussis toxin.
Imamichi
T
T
Department of Hygienic Chemistry, Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
Koyama
J
J
D000818:Animals; D000936:Antigen-Antibody Complex / Q000276:immunology; D000943:Antigens, Differentiation / Q000145:classification / Q000502:physiology*; D002118:Calcium / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D006168:Guinea Pigs; D007074:Immunoglobulin G / Q000378:metabolism; D007132:Immunoglobulin Isotypes / Q000378:metabolism; D066298:In Vitro Techniques; D007295:Inositol Phosphates / Q000378:metabolism; D008264:Macrophages / Q000502:physiology*; D010047:Ovalbumin / Q000276:immunology; D037342:Pertussis Toxin; D010716:Phosphatidylinositols / Q000378:metabolism*; D011961:Receptors, Fc / Q000145:classification / Q000502:physiology*; D017452:Receptors, IgG; D015398:Signal Transduction; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D000936:Antigen-Antibody Complex; D000943:Antigens, Differentiation; D007074:Immunoglobulin G; D007132:Immunoglobulin Isotypes; D007295:Inositol Phosphates; D010716:Phosphatidylinositols; D011961:Receptors, Fc; D017452:Receptors, IgG; D010566:Virulence Factors, Bordetella; D004533:Egtazic Acid; D010047:Ovalbumin; D037342:Pertussis Toxin; D002118:Calcium