DETECTION AND CHARACTERIZATION OF B CELL EPITOPES ON BETA2-GLYCOPROTEIN I

KA Cockerill, MD Linnik, GM Iverson

Autoantibodies in antiphospholipid syndrome react predominantly with the plasma protein beta2-glycoprotein I (B2GPI). Work by a large number of investigators has led to considerable progress in detecting and understanding B2GPI reactivity with autoantibodies. Characterization of B cell epitopes on B2GPI has benefited from an appreciation of its interactions with anionic phospholipids and a variety of microplate surfaces. In particular, autoantibodies to B2GPI are of sufficiently low affinity to require high concentrations of antigen for detectable reactivity. Moreover, some microplate surfaces do not support the proper orientation of B2GPI to allow display of epitopes in a manner accessible to autoantibodies. These concepts have helped to explain previous notions that exposure to cryptic B2GPI epitopes may require interactions with anionic surfaces. Finally, we review evidence identifying a dominant B cell epitope that is partially define by residues Gly40 and Arg43 on the amino terminal domain of B2GPI.

Published in
Clinical Immunology 2004
Volume 112:pp 129-135