Capture ELISA with Abrin/Ricin near Neighbor Extracts == To evaluate the specificity of the monoclonal abrin antibodies against other herb ribosome-inactivating proteins (RIPs), extracts from 46 abrin and ricin near neighbors were obtained from Julie R. comparable to other reported capture ELISAs using polyclonal antibodies as either capture or detector. Keywords:abrin,abrus precatorius, ELISA, monoclonal antibodies, ribosome-inactivating protein == 1. Introduction == Abrin and ricin are both members of the Type II family of ribosome-inactivating proteins (RIP) that inhibit eukaryotic protein synthesis leading to apoptosis and cell death. Abrin is found in jequirity seeds or rosary peas of the herb,Abrus precatoriusL., and native to tropical/subtropical regions of the world. Abrin like ricin is considered a Select Agent due to its potential use in bio warfare. Abrin is a heterodimeric protein toxin consisting of an A-chain and a B-chain linked together with a single disulfide. The catalytic active A-chain is usually anN-glycosidase that deadenylates the rat 28S ribosomal RNA at position 4324 [1] thereby preventing Bivalirudin TFA ribosomes from binding to elongation factor (EF) 1 and 2 leading to inhibition of protein synthesis and eventual cell death [2,3,4,5,6,7]. Abrin B-chain is a lectin that binds to cell surface carbohydrate receptors facilitating receptor-mediated endocytosis of the AB toxin. Abrin isolated fromAbrus precatoriusseeds is a heterogeneous mixture Rabbit polyclonal to EGFLAM [7,8,9]. Multiple isoforms have been reported, and each form has different toxicity [8,9,10,11,12,13,14]. In addition to these toxin isoforms, the presence of a 120 kDa heterotetrameric species, referred to as the agglutinin (APA-1), also can be isolated from seed preparations. APA-1 consists of two A-chains and two B-chains that are stabilized through Bivalirudin TFA hydrophilic and hydrophobic interactions [15]. Though APA-1 and abrin toxin isoforms have very similar sequences, APA-1 has reduced toxicity as compared to abrin [8,16,17]. Abrin intoxication can occur via multiple routes that affect its toxicity. The routes of intoxication are gastrointestinal, inhalational, or cutaneous. Abrin intoxication cases have been attributed to the accidental ingestion ofA. precatoriusseeds by children. Since there is no antidote for abrin poisoning, the only available treatment is usually supportive care to mitigate the effects of the toxin. In the case of abrin intoxication via the ingestion, the current treatment consists of inducing emesis, gastric lavage, activated charcoal, and whole bowel irrigation [3]. The LD50of abrin for humans has been reported to range from 101000 g/kg via oral ingestion and 3.3 g/kg if injected [18]. In mice, Bivalirudin TFA abrin has been shown to be 31.4 times more lethal than ricin with an LD of 0.7 g/kg vs. 22 g/kg when given intravenously [19]. Multiple technologies (electrospray MS, portable sensor, etc.) have been developed to detectl-abrine (N-methyltryptophan) [18,20,21] as a biomarker for abrin exposure. ELISA, ECL, and lateral flow technologies have been reported to detect abrin. Earlier work reported that polyclonalmonoclonal antibody, as well as polyclonalpolyclonal based capture ELISAs and ECL assays have limits of detection (LODs) ranging from 0.10.5 ng/mL in buffer [15]. In the same study, the authors report that this ECL platform had LODs from 0.10.5 ng/mL in different food matrices whereas the ELISAs had higher LODs (0.510 ng/mL). Other studies detecting abrin in food using monoclonal antibodies as capture with polyclonal antibodies as detector reported an LOD of 0.7 ng/mL in PBS or PBSTM [22]. A monoclonal capture with a polyclonal detector ELISA was reported to have a LOD in buffer of 0.5 g/L (0.5 ng/mL) [23]. We speculated that a capture ELISA based on monoclonal antibodies for both capture and.