Ricin is a potent toxin and a potential bioterrorism weapon with no specific countermeasures or vaccines available. The holotoxin is composed of two polypeptide chains linked by a single disulfide bond: the A-chain (RTA), which is an N-glycosidase enzyme, and the B-chain (RTB), a lectin polypeptide that binds galactosyl moieties on the surface of the mammalian target cells. Previously (McHugh e...

Ricin can be detected in cosmetics at 0.005 microg/mL in the analytical sample using lateral flow devices (LFDs). Wheat germ, an ingredient used in skin care products is also a potential source of wheat lectin. False positives were observed when wheat lectin was added to LFDs from two manufacturers, irrespective of whether the LFD was specific for ricin, Staphylococcus enterotoxin B (SEB), or b...

The kinetics of protein synthesis inhibition in a cell-free system from rabbit reticulocyte lysate was studied after addition of abrin and ricin and the isolated A chains. The toxin A chains inhibited protein synthesis at a rate proportional to the amount added. When intact toxins were added to the reticulocyte lysate, the kinetics of protein synthesis inhibition indicated that the A chains mus...

The use of microorganisms or toxins as weapons of death and fear is not a novel concept; however, the modes by which these agents of bioterrorism are deployed are increasingly clever and insidious. One mechanism by which biothreats are readily disseminated is through a nation's food supply. Ricin, a toxin derived from the castor bean plant, displays a strong thermostability and remains active a...

Ricin toxin's binding subunit (RTB) is a galactose-/N-acetylgalactosamine (Gal/GalNac)-specific lectin that mediates uptake and intracellular trafficking of ricin within mammalian cells. Structurally, RTB consists of two globular domains, each divided into three homologous sub-domains (α, β, γ). In this report, we describe five new murine IgG monoclonal antibodies (mAbs) against RTB: MH3, 8A1, ...

Ricin is a type II ribosome-inactivating toxin that catalytically inactivates ribosomes ultimately leading to cell death. The toxicity of ricin along with the prevalence of castor beans (its natural source) has led to its increased notoriety and incidences of nefarious use. Despite these concerns, there are no licensed therapies available for treating ricin intoxication. Here, we describe the d...

The plant A/B toxin ricin represents a heterodimeric glycoprotein belonging to the family of ribosome inactivating proteins, RIPs. Its toxicity towards eukaryotic cells results from the depurination of 28S rRNA due to the N-glycosidic activity of ricin toxin A chain, RTA. Since the extention of RTA by a mammalian-specific endoplasmic reticulum (ER) retention signal (KDEL) significantly increase...

The aim of this work was to investigate the potential interactions between intestinal absorbance and ricin poisoning. The Caco-2 cell monolayer and everted intestinal sac (VEIS) models were used. The distribution of ricin in CD-1 mice intoxicated with 0.1 mg/kg of ricin intragastrically was determined by immunohistochemistry. The results showed that ricin could not transfer across the healthy C...

Ricin, a plant-derived toxin originating from the seeds of Ricinus communis (castor beans), is one of the most lethal toxins known, particularly if inhaled. Ricin is considered a potential biological threat agent due to its high availability and ease of production. The clinical manifestation of pulmonary ricin intoxication in animal models is closely related to acute respiratory distress syndro...

Ricin is a potent glycoprotein toxin that is structurally composed of two subunits joined via a disulfide bond: a ~30 kDa subunit A (RTA) and a ~32 kDa subunit B (RTB). There are fears of ricin being used as a weapon for warfare and terrorism and, as such, there is an increasing need for the development of immunodiagnostic reagents targeted towards this toxin. This article describes the product...