Glycoprotein methods protocols - biotechnology 048-9-129-141.pdf

Synthetic Peptides for Antimucin Antibodies 129

129

From: Methods in Molecular Biology, Vol. 125: Glycoprotein Methods and Protocols: The Mucins

Edited by: A. Corfield © Humana Press Inc., Totowa, NJ

12

Synthetic Peptides for the Analysis and Preparation

of Antimucin Antibodies

Andrea Murray, Deirdre A. O’Sullivan, and Michael R. Price

1. Introduction

Since the mid-1980s, the family of high molecular weight glycoproteins known as

mucins have evoked considerable interest among those in the field of cancer research.

Mucins, which are constituents of mucus, have a lubricating and protective function in

normal epithelial tissue (1). However, expression of mucin by the cancer cell is often

highly disorganized and upregulated, sometimes to the extent that mucin can be

detected in the circulation of the cancer patient. These changes in expression of mucin

observed in neoplasia have led to the exploitation of some members of the mucin

family as circulating tumor markers (2,3) or targets for diagnostic imaging (4–6) and

therapy of cancer.

The first mucin to have its primary amino acid sequence determined, MUC1, is also

the most extensively studied. This molecule is highly immunogenic, and a consider￾able number of anti-MUC1 monoclonal antibodies (mAbs) and fragments have been

produced by various methods. Some of these have found applications for radio￾immunoscintigraphy and targeted therapy of cancer, and others have been used to

detect circulating MUC1. Although such studies have yielded promising results, their

present application is somewhat restricted. In this age of genetic and protein engineer￾ing, we have, at our disposal, the technology to design antibodies with ideal character￾istics of size, affinity, and specificity for any desired application. However, before

considering such ambitions, we must first gain an understanding of the molecular

interactions between epitope and paratope when an antibody binds to its antigen. It is

essential that key residues involved in the interaction are identified so that a model of

how the interaction takes place on a three-dimensional level can be constructed. This

identification will enhance our ability to design antibodies with the correct character￾istics for our chosen application.