abrin

Abrin is a highly toxic protein derived from the seeds of the leguminous plant Abrus precatorius, commonly known as the rosary pea. It belongs to the ribosome-inactivating protein (RIP) family and forms a disulfide-linked A–B heterodimer. The B chain binds to cell surface receptors, promoting cellular entry, while the A chain acts as an enzyme that removes a specific adenine residue from 28S ribosomal RNA, inactivating ribosomes and halting protein synthesis. This disruption can lead to cell death and, depending on exposure and dose, can cause severe organ damage.

Most human exposures occur through ingestion of raw or chewed seeds; inhalation of aerosols or contact with skin can also cause poisoning. Seeds are extremely toxic if disrupted, and accidental poisonings have been reported, particularly in children. Symptoms typically appear within hours and may include irritation of the mouth and throat, nausea, vomiting, abdominal pain, and diarrhea, followed by dehydration and, in severe cases, fever, seizures, organ failure, or death. The clinical course and outcome depend on the amount of toxin exposure and the route of exposure. There is no widely available antidote; management is supportive and requires medical care, often in an intensive care setting.

In research contexts, abrin has been studied as a tool for understanding protein synthesis and as a basis for experimental targeted toxins. Its handling is tightly regulated, reflecting its extreme toxicity and potential hazards. Public health guidance emphasizes prevention of ingestion, careful handling, and prompt medical evaluation after suspected exposure.