Epitope Studies with Anti-β2-glycoprotein I Antibodies from Autoantibody and Immunized Sources
- Resource Type
- Article
- Authors
- Reddel, Stephen W; Wang, Ying Xia; Sheng, Yong Hua; Krilis, Steven A
- Source
- Journal of Autoimmunity; September 2000, Vol. 15 Issue: 2 p91-96, 6p
- Subject
- Language
- ISSN
- 08968411; 10959157
This paper examines the methodology of anti-β2-glycoprotein I (β2-GPI) epitope determination and provides further epitope studies using human sera containing anti-β2-GPI autoantibodies. Studies in this field may be misleading as the antigen coating density using mutant forms of β2-GPI may be below the threshold required for monogamous divalent binding by low affinity anti-β2-GPI autoantibodies, while being easily detected by high affinity anti-β2-GPI from immunized animals. The antigen density threshold effect is found in anti-β2-GPI autoantibodies from humans and from monoclonal anti-β2-GPI derived from mice with models of autoimmune disease. Anti-β2-GPI from an autoimmune mouse and from 18/21 human sera did not bind above background levels to a domain-I-deleted mutant. In addition, single point mutations in domain I result in dramatic changes in the binding of many human sera containing anti-β2-GPI. These findings support a conclusion that domain I of β2-GPI contains significant epitopes for the anti-β2-GPI antibodies found in the antiphospholipid syndrome.