Identification of prostate specific membrane antigen (PSMA) as the target of monoclonal antibody 107-1A4 by proteinchip®; array, surface-enhanced laser desorption/ionization (seldi) technology
Article first published online: 3 APR 2001
Copyright © 2001 Wiley-Liss, Inc.
International Journal of Cancer
Volume 92, Issue 6, pages 871–876, 15 June 2001
How to Cite
Wang, S., Diamond, D. L., Hass, G. M., Sokoloff, R. and Vessella, R. L. (2001), Identification of prostate specific membrane antigen (PSMA) as the target of monoclonal antibody 107-1A4 by proteinchip®; array, surface-enhanced laser desorption/ionization (seldi) technology. Int. J. Cancer, 92: 871–876. doi: 10.1002/ijc.1272
- Issue published online: 3 MAY 2001
- Article first published online: 3 APR 2001
- Manuscript Accepted: 29 JAN 2001
- Manuscript Revised: 24 JAN 2001
- Manuscript Received: 12 DEC 2000
- prostate specific membrane antigen;
- mass spectrometry;
- prostate cancer
Recently we described the generation of the prostate tissue-specific monoclonal antibody (MAb) 107-1A4, its expression pattern and preliminary targeting of human prostate cancer xenografts. In this report we demonstrate that the target antigen for MAb 107-1A4 is prostate-specific membrane antigen (PSMA) using immunoaffinity absorption followed by SDS-PAGE and mass spectrometric analysis of peptides produced by in-gel tryptic digestion. The identity of the antigen has been confirmed by Western blots using MAbs of known specificity. MAb 107-1A4 is not reactive on Western blots. The conformational epitope for 107-1A4 is on the extracellular domain of PSMA. In competition studies, the binding of MAb 107-1A4 to LNCaP cells is inhibited by itself but not by any other of several other anti-PSMA MAbs, suggesting that the epitope may be unique. These results suggest that 107-1A4 is reactive to a conformational epitope in the external domain of PSMA that is unique among the panel of anti-PSMA MAbs in this study. Furthermore this work demonstrates the ability of mass spectroscopy to elucidate antibody-ligand interaction. © 2001 Wiley-Liss, Inc.