title: 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.affiliation: National Cell Bank of Iran, Pasteur Institute of Iran, Tehran, Iran.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Sharifzadeh
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Rahbarizadeh
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Shokrgozar
authors.forename: Davoud
authors.initials: D
authors.lastname: Ahmadvand
authors.forename: Fereidoun
authors.initials: F
authors.lastname: Mahboudi
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Rahimi Jamnani
authors.forename: Seyed Hamid
authors.initials: SH
authors.lastname: Aghaee Bakhtiari
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology; D000917:Antibody Formation; D000918:Antibody Specificity / Q000276:immunology; D000951:Antigens, Neoplasm / Q000276:immunology*; D002162:Camelus / Q000276:immunology; D045744:Cell Line, Tumor; D061505:Cell Surface Display Techniques / Q000379:methods; D003429:Cross Reactions / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D000939:Epitopes / Q000276:immunology; D006023:Glycoproteins / Q000276:immunology*; D019073:HT29 Cells; D006801:Humans; D008297:Male; D051379:Mice; D018396:Mucin-1 / Q000276:immunology; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000276:immunology; D061905:Single-Domain Antibodies / Q000276:immunology*
chemical_list: D000906:Antibodies; D000951:Antigens, Neoplasm; D000939:Epitopes; D006023:Glycoproteins; D018396:Mucin-1; D018719:Erb-b2 Receptor Tyrosine Kinases; D061905:Single-Domain Antibodies; C047052:tumor-associated antigen 72