A Monoclonal–Monoclonal Antibody Based Capture ELISA for Abrin

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. The capture ELISA based on this capture–detector mAb pair had a limit of detection (L.O.D) of ≈1 ng/mL measured using three independent experiments. 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.

Novel Phage Display-Derived Anti-Abrin Antibodies Confer Post-Exposure Protection against Abrin Intoxication

“…Over the last decade, several anti-abrin monoclonal antibodies (mABs) were isolated, several targeting ATA and only one targeting ATB. The mABs were found to be specific and were successfully implemented in several formats of toxin detection [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. The effectiveness of anti-abrin mABs neutralization in vivo was demonstrated only in two cases, where the antibodies were given as a prophylactic treatment [ 6 , 8 ], thus highlighting the need for potent anti-abrin antibodies that will provide effective post-exposure therapy.…”

Ultrafast protein digestion using an immobilized enzyme reactor following high-resolution mass spectrometry analysis for rapid identification of abrin toxin

“…11 However, during further purification of abrin, the first two markers are lost in the preparation process. The identification of abrin protein relies on either antigen recognition using antibodies, such as enzyme-linked immunosorbent assay (ELISA), 12,13 immunochromatography assay (ICA), 14 and electrochemiluminescence (ECL), 15 or sequence characterization by mass spectrometry (MS). 16,17 Antibodybased methods have high sensitivity, but poor specificity and do not discern closely related toxin variants.…”

Ribosome Inactivating Proteins: From Plant Defense to Treatments against Human Misuse or Diseases

“…Thus, there is a need for detection and decontamination tools. Tam et al set up a two-monoclonal antibody-based ELISA that can detect as low as 1 ng/mL of abrin and that shows no false positive detection of other plant RIPs [ 10 ]. The same team showed that while various pH treatments of the toxin did not affect its activity, heating above 74 °C completely inactivated its capacity to kill cells and mice.…”