Meridian Life Science (MLS) is offering free copies of Timothy Yi's publication 'Intact Ricin Analysis in Foods using Enzyme-Linked Immunosorbent Assay (Elisa)'.
MLS's portfolio of infectious disease and toxin products includes antibodies to bioterrorism agents such as ricin.
Ricin is derived from the castor bean and is one of the most toxic substances known.
It is a 60kDa glycoprotein that consists of two polypeptide chains, chains A (RTA) and B (RTB), linked by a single disulfide bond.
For ricin to be toxic, both RTA and RTB must remain in the non-reduced form.
The most widely used immunoassays for detecting ricin in foods screen for castor-bean residue.
These tests can be misleading, however, as they cross react with ricinus communis agglutinin I (RCA I or RCA120), a glycoprotein from castor beans that is much less toxic than ricin.
The current immunoassays also detect the individual polypeptides ricin A chain and ricin B chain from the reduced form of ricin, which are non-toxic.
The lack of specificity in current immunoassays makes it difficult to detect intact ricin and quantify the amount in foods.
Timothy Yi, a chemist with the FDA Forensic Chemistry Center in Cincinnati, OH, recently used catalogue C86921M, MAb to ricin, RCA 60 A-chain, Clone # RA999 and catalogue # C86922M, MAb to ricin, RCA 60 B-chain, Clone # RB999 to develop a two-antibody indirect sandwich Elisa to detect intact ricinus communis agglutinin II (RCA II or RCA 60).
When used as a pair in a sandwich immunoassay, the ricin antibodies detected intact ricin without significant cross reactivity with RCA I or RCA120.
Yi has published his work in a FDA laboratory information bulletin.
