The Journal of Experimental Medicine
Avanti Polar Lipids, Inc.
  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents

Published 11 March 2002. doi:10.1084/jem.20012024
This Article
Right arrow Full Text
Right arrow Full Text (PDF, 100K)
Right arrow PPT slides of all figures
Right arrow Alert me when this article is cited
Right arrow Citation Map
Services
Right arrow Email this article
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new content in the JEM
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by da Silveira, S. A.
Right arrow Articles by Izui, S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by da Silveira, S. A.
Right arrow Articles by Izui, S.
Social Bookmarking
 Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Facebook   Add to Reddit   Add to Technorati   Add to Twitter  
What's this?
© Rockefeller University Press, 0022-1007/2002/3/665/ $5.00
The Journal of Experimental Medicine, Volume 195, Number 6, March 18, 2002 665-672


Original Article

Complement Activation Selectively Potentiates the Pathogenicity of the IgG2b and IgG3 Isotypes of a High Affinity Anti-Erythrocyte Autoantibody

Samareh Azeredo da Silveira1, Shuichi Kikuchi1, Liliane Fossati-Jimack2, Thomas Moll1, Takashi Saito3, J. Sjef Verbeek4, Marina Botto2, Mark J. Walport2, Michael Carroll5 and Shozo Izui1

1 Department of Pathology, University of Geneva, 1211 Geneva 4, Switzerland
2 Rheumatology Section, Hammersmith Campus, Imperial College School of Medicine, London W12 0NN, United Kingdom
3 Department of Molecular Genetics, Chiba University Graduate School of Medicine, Chiba 260, Japan
4 Department of Human and Clinical Genetics, Leiden University Medical Center, 2300 RA Leiden, Netherlands
5 Center for Blood Research and Department of Pathology, Harvard Medical School, Boston, MA 02115

Address correspondence to Dr. Shozo Izui, Department of Pathology, C.M.U., 1211 Geneva 4, Switzerland. Phone: 022-70-25-741; Fax: 022-70-25-746; E-mail: Shozo.Izui{at}medecine.unige.ch

By generating four IgG isotype-switch variants of the high affinity 34–3C anti-erythrocyte autoantibody, and comparing them to the IgG variants of the low affinity 4C8 anti-erythrocyte autoantibody that we have previously studied, we evaluated in this study how high affinity binding to erythrocytes influences the pathogenicity of each IgG isotype in relation to the respective contributions of Fc{gamma} receptor (Fc{gamma}R) and complement. The 34–3C autoantibody opsonizing extensively circulating erythrocytes efficiently activated complement in vivo (IgG2a = IgG2b > IgG3), except for the IgG1 isotype, while the 4C8 IgG autoantibody failed to activate complement. The pathogenicity of the 34–3C autoantibody of IgG2b and IgG3 isotypes was dramatically higher (>200-fold) than that of the corresponding isotypes of the 4C8 antibody. This enhanced activity was highly (IgG2b) or totally (IgG3) dependent on complement. In contrast, erythrocyte-binding affinities only played a minor role in in vivo hemolytic activities of the IgG1 and IgG2a isotypes of 34–3C and 4C8 antibodies, where complement was not or only partially involved, respectively. The remarkably different capacities of four different IgG isotypes of low and high affinity anti-erythrocyte autoantibodies to activate Fc{gamma}R-bearing effector cells and complement in vivo demonstrate the role of autoantibody affinity maturation and of IgG isotype switching in autoantibody-mediated pathology.

Key Words: autoimmune hemolytic anemia • complement receptor • Fc receptor • IgG isotype • phagocytosis


Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Facebook Facebook   Add to Reddit Reddit   Add to Technorati Technorati   Add to Twitter Twitter    What's this?


This article has been cited by other articles:



  Home | Help | Feedback | Subscriptions | Archive | Search
TABLE OF CONTENTS