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United States Department of Agriculture

Agricultural Research Service

Research Project: INNOVATIVE MATERIALS FOR USE IN MYCOTOXIN DETECTION

Location: Bacterial Foodborne Pathogens & Mycology Research Unit

Title: Production and characterization of a single chain variable fragment (scFv) for the mycotoxin deoxynivalenol

Authors
item Maragos, Chris
item Li, Lan -
item Chen, Donghai -

Submitted to: Food and Agricultural Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 17, 2011
Publication Date: March 31, 2012
Citation: Maragos, C.M., Li, L., Chen, D. 2012. Production and characterization of a single chain variable fragment (scFv) for the mycotoxin deoxynivalenol. Food and Agricultural Immunology. 23(1):51-67.

Interpretive Summary: Deoxynivalenol (DON) is a mycotoxin produced by certain fungi that can infest wheat, barley, and corn. In crops one of the diseases caused by these fungi is Fusarium Head Blight, which results in significant losses to the quality and value of grain worldwide. Because of the toxicity of DON, and the desire to protect human and animal health, extensive monitoring for this toxin is conducted in commodities and foods. As part of efforts to improve detection of the toxin, new materials for selectively binding the toxin have been developed. In this report a cell line producing a monoclonal antibody (Mab) recognizing DON was used as the starting point in the development of a recombinant single chain variable fragment (scFv) antibody for DON. Results indicate this approach can allow the scFv to be produced in bacterial systems, which can make its production less expensive. These findings are significant in determining the materials most useful in mycotoxin detection assays.

Technical Abstract: Deoxynivalenol (DON)is a mycotoxin produced by certain fungi that infest cereal grains worldwide. A hybridoma cell line producing a monoclonal antibody (Mab) recognizing DON was used as the starting point in the development of a recombinant single chain variable fragment (scFv) antibody. The scFv was characterized using two immunoassay formats: competitive direct enzyme-linked immunosorbent assay (CD-ELISA) and biolayer interferometry (BLI). The response of the CD-ELISA based upon the scFv was slightly poorer than the response based upon the intact Mab (IC50s of 36.1 and 13.8 ng/ml respectively for DON). The cross-reactivity pattern of the scFv for related trichothecene analogs did not change substantially from that of the intact Mab. The real-time binding of the antibodies to an immobilized DON-protein conjugate was also monitored. In competitive BLI assays the IC50s using the scFv and Mab were 68.3 and 15.8 ng/ml, respectively. The results suggest that removal of the major framework regions of the Mab slightly reduced the sensitivity of the resulting assays, however the selectivity of the toxin-binding site was not significantly affected.

Last Modified: 8/22/2014
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