title: Green fluorescent-conjugated anti-CEA single chain antibody for the detection of CEA-positive cancer cells.
abstract: According to World Health Organization (WHO), cancer is a leading cause of death worldwide, accounting for 7.4 million deaths (around 13% of all deaths) in 2004. Monoclonal/recombinant antibodies, which specifically target clinical biomarkers of disease, have increasingly been applied as powerful tools in cancer imaging and therapy, a fact that is highlighted by some nine FDA-approved monoclonal antibodies (MAbs) or their immunoconjugates (as of December 2008) for use in cancer treatment. In this study, five monoclonal antibodies (MAbs) were generated and characterized against carcinoembryonic antigen (CEA), which is widely used clinically as both a blood and tissue tumor marker of epithelial malignancy. Variable domains (VH and VL) of one the stable MAbs with highest affinity were PCR-amplified and assembled as single-chain antibody fragment (scFv). Following the cloning and expression of scFv antibody fragments in Escherichia coli, the functional binding and specificity of the recombinant antibody were confirmed by ELISA. To develop a direct in vitro detection of CEA-positive cancer cells, scFv DNA was genetically fused to enhanced green fluorescent protein (EGFP) gene and expressed in bacteria. The chimeric fluorescent protein is able to specifically detect CEA-positive cell lines; no cross-reactivity was observed with a negative control cell line. This strategy will likely allow the establishment of a rapid, single-step detection assay of CEA, which is considered to be one of the best predictors of malignancy among all other tumor markers.
authors.affiliation: Khatam Institute of Higher Education, Tehran, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Salavatifar
authors.forename: Shadi
authors.initials: S
authors.lastname: Amin
authors.forename: Zahra Moghaddassi
authors.initials: ZM
authors.lastname: Jahromi
authors.forename: Nasrin
authors.initials: N
authors.lastname: Rasgoo
authors.forename: Nasrin
authors.initials: N
authors.lastname: Rastgoo
authors.forename: Mehdi
authors.initials: M
authors.lastname: Arbabi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D014408:Biomarkers, Tumor / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*; D002272:Carcinoembryonic Antigen / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000096:biosynthesis; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli; D049452:Green Fluorescent Proteins / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D006825:Hybridomas / Q000276:immunology / Q000378:metabolism; D007167:Immunotherapy / Q000379:methods*; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D009369:Neoplasms / Q000175:diagnosis* / Q000628:therapy*; D017422:Sequence Analysis, DNA; D057127:Single-Chain Antibodies / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D013050:Spectrometry, Fluorescence
chemical_list: D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen; D018076:DNA, Complementary; D057127:Single-Chain Antibodies; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins