Differentiation, Quantification and Identification of Abrin and Agglutinin.

Abrin, the toxic lectin from the rosary pea plant has gained considerable interest in the recent past due to its potential malevolent use. However, reliable and easy-to-use assays for the detection and discrimination of abrin from related plant proteins such as agglutinin or the homologous toxin ricin from are sparse. To address this gap, a panel of highly specific monoclonal antibodies was generated against abrin and the related agglutinin. These antibodies were used to establish two sandwich ELISAs to preferentially detect abrin or agglutinin (limit of detection 22 pg/mL for abrin; 35 pg/mL for agglutinin). Furthermore, an abrin-specific lateral flow assay was developed for rapid on-site detection (limit of detection ~1 ng/mL abrin). Assays were validated for complex food, environmental and clinical matrices illustrating broad applicability in different threat scenarios. Additionally, the antibodies turned out to be suitable for immuno-enrichment strategies in combination with mass spectrometry-based approaches for unambiguous identification. Finally, we were able to demonstrate for the first time how the developed assays can be applied to detect, identify and quantify abrin from a clinical sample derived from an attempted suicide case involving .