Development of oligoclonal nanobodies for targeting the tumor-associated glycoprotein 72 antigen.

Abstract

The tumor-associated glycoprotein 72 (TAG-72) is a membrane mucin whose over-expression is correlated with advanced tumor stage and increased invasion and metastasis. In this study, we identified a panel of four nanobodies, single variable domains of dromedary heavy-chain antibodies that specifically recognize the TAG-72 antigen. All selected nanobodies were shown to selectively bind to this cancer-related molecule with low-nanomolar affinities and do not cross-react with other antigens, such as MUC1 or HER2. Furthermore, they can detect TAG-72 in concentrations as low as 5 U/ml which is valuable in sensitive detection of this molecule in cancerous patients. Cell ELISA experiments proved their ability for binding to the native target antigen on TAG-72 expressing cells while not showing any reactivity to HT-29 cells, a TAG-72-negative cell line. Using competition studies, we found that each nanobody recognizes a distinct epitope on the TAG-72 antigen that is different from the one recognized by the mouse anti-TAG-72 antibody, CC49. Considering their high specificity, reduced immunogenicity and multi-targeting behavior, these oligoclonal nanobodies represent a promising tool to target TAG-72 over-expressing tumor cells.

• Authors: Zahra Sharifzadeh, Fatemeh Rahbarizadeh, Mohammad Ali Shokrgozar, Davoud Ahmadvand, Fereidoun Mahboudi, Fatemeh Rahimi Jamnani, Seyed Hamid Aghaee Bakhtiari
• Journal: Molecular biotechnology (Mol Biotechnol) Vol. 54 Issue 2 Pg. 590-601 (Jun 2013) ISSN: 1559-0305 [Electronic] United States
• PMID: 23015323 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antibodies
• Antigens, Neoplasm
• Epitopes
• Glycoproteins
• Mucin-1
• Single-Domain Antibodies
• tumor-associated antigen 72
• Receptor, ErbB-2

Topics

• Animals
• Antibodies (immunology)
• Antibody Formation
• Antibody Specificity (immunology)
• Antigens, Neoplasm (immunology)
• Camelus (immunology)
• Cell Line, Tumor
• Cell Surface Display Techniques (methods)
• Cross Reactions (immunology)
• Enzyme-Linked Immunosorbent Assay (methods)
• Epitopes (immunology)
• Glycoproteins (immunology)
• HT29 Cells
• Humans
• Male
• Mice
• Mucin-1 (immunology)
• Receptor, ErbB-2 (immunology)
• Single-Domain Antibodies (immunology)