Background: CA 125 antigenic domains appear to reside within a region containing 156-amino acid sequence repeats. Surprisingly, anti-CA 125 antibodies can be classified into three families (groups A, B and C) indicating limited epitope diversity. In this study we describe the heterologous expression of a CA 125 repeat unit (R11) and an analysis of its epitope topography. Methods: R11 was expressed using a baculovirus approach and purified from culture supernatants by sequential ion exchange chromatography. Monoclonal antibody binding was assessed using antigen capture and cross-inhibition methods. Results: The recombinant repeat was purified to 2.5 × 107 U/mg. Although a number of group A and B monoclonal antibodies were found to bind R11, the prototype antibody OC125 (group A) showed little reactivity. However, the prior binding of some group B monoclonal antibodies dramatically enhanced subsequent OC125 binding. Low monoclonal antibody reactivity to R11 correlated well with poor binding to SDS-denatured human ascites CA 125. Conclusion: The ability to ‘activate’ R11 epitopes indicates that some may not be displayed optimally on isolated repeats. This observation, together with the concordance between monoclonal antibody binding to R11 and denatured CA 125, suggests that a number of epitopes are preferentially displayed only when contained within multiple repeat domains.

This content is only available via PDF.
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.