title: Development and utilization of camelid VHH antibodies from alpaca for 2,2',4,4'-tetrabrominated diphenyl ether detection.
abstract: An antibody-based analytical method for the detection of a chemical flame retardant using antibody fragments isolated from an alpaca has been developed. One specific chemical flame retardant congener, 2,2',4,4'-tetrabrominated diphenyl ether (BDE-47), is often the major poly-BDE (PBDE) congener present in human and environmental samples and that which is the most frequently detected. An alpaca was immunized with a surrogate of BDE-47 covalently attached to a carrier protein. The resulting mRNA coding for the variable domain of heavy-chain antibodies (VHH) were isolated, transcribed to cDNA, and cloned into a phagemid vector for phage display library construction. Selection of VHHs recognizing BDE-47 was achieved by panning under carefully modified conditions. The assay sensitivity for detecting BDE-47 was down to the part-per-billion (microgram per liter) level. Cross-reactivity analyses confirmed that this method was highly selective for BDE-47 and selected hydroxylated metabolites. When exposed to elevated temperatures, the camelid VHH antibodies retained more reactivity than a polyclonal antibody developed to the same target analyte. The use of this VHH antibody reagent immobilized onto a Au electrode for impedance biosensing demonstrates the increased versatility of VHH antibodies.
authors.affiliation: Department of Entomology and Nematology, University of California-Davis , Davis, California 95616, United States.
authors.forename: Candace R S
authors.initials: CR
authors.lastname: Bever
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Majkova
authors.forename: Rajeswaran
authors.initials: R
authors.lastname: Radhakrishnan
authors.forename: Ian
authors.initials: I
authors.lastname: Suni
authors.forename: Mark
authors.initials: M
authors.lastname: McCoy
authors.forename: Yanru
authors.initials: Y
authors.lastname: Wang
authors.forename: Julie
authors.initials: J
authors.lastname: Dechant
authors.forename: Shirley
authors.initials: S
authors.lastname: Gee
authors.forename: Bruce D
authors.initials: BD
authors.lastname: Hammock
mesh_terms: D000818:Animals; D001435:Bacteriophages / Q000276:immunology; D002161:Camelids, New World; D058266:Dielectric Spectroscopy; D055768:Halogenated Diphenyl Ethers / Q000032:analysis*; D061905:Single-Domain Antibodies / Q000276:immunology*
chemical_list: D055768:Halogenated Diphenyl Ethers; D061905:Single-Domain Antibodies; C511295:2,2',4,4'-tetrabromodiphenyl ether