|HODGE, DAVID - Us Deparment Of Homeland Security|
Submitted to: Toxins
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/13/2017
Publication Date: 10/18/2017
Publication URL: https://handle.nal.usda.gov/10113/6472266
Citation: Tam, C.C., Cheng, L.W., He, X., Merrill, P.A., Hodge, D., Stanker, L.H. 2017. A monoclonal-monoclonal antibody based capture elisa for abrin. Toxins. 9(10):328. https://doi.org/10.3390/toxins9100328.
Interpretive Summary: Abrin is a highly potent toxin found in the seeds or rosary peas of the plant Abrus precatoriusis. Because of its high toxicity it is considered a select agent. Intoxication can occur via gastrointestinal, inhalation or cutaneous exposure. Because of its potential use as a bioterrorist agent, rapid detection in foods is highly desirable. We report here development of a monoclonal antibody based assay with a detection limit in the low ng/mL range. An advantage of using monoclonal antibodies is this test is the long-term availability of highly consistent reagents for the test. The test gave no false positives when evaluated using a panel of near neighbor plant proteins and it can be completed in a few hours. Thus, this test furthers our ability to monitor for toxin and improves the safety of the US food supply.
Technical Abstract: Abrin, one of the most highly potent toxins in the world, is derived from the plant, Abrus precatorius. Because of its high toxicity, it poses potential bioterror risks. Therefore, a need exists for new reagents and technologies that would be able to rapidly detect abrin contamination as well as lead to new therapeutics. We report here a group of abrin specific monoclonal antibodies (mAbs) that recognize abrin A-chain, intact A-B chain toxin, and agglutinin by Western blot. Additionally, these mAbs were evaluated for their ability to serve as capture antibodies for a sandwich (capture) ELISA. All possible capture-detector pairs were evaluated and the best antibody pair identified and optimized for a capture ELISA. This capture-detector mAb pair in an ELISA had a limit of detection (L.O.D) of ˜ 1 ng/mL. The assay did not reveal any false positives with extracts containing other potential ribosome-inactivating proteins (RIPs). Thus this new capture ELISA uses mAbs for both capture and detection; has no cross-reactivity against other plant RIPs; and has a sensitivity comparable to other reported capture ELISAs using polyclonal antibodies as either capture or detector.