Feasibility of Immunodiagnostic Devices for the Detection of Ricin, Amanitin, and T-2 Toxin in Food

Abstract

Qualitative and quantitative comparisons were conducted of commercially available immunodiagnostic devices for the detection of three select agents with oral LD50 values > or = 0.1 mg/kg of body weight. Ricin (oral LD50 > 1 mg/kg), amanitin (oral LD50 approximately 0.1 mg/kg), and T-2 toxin (oral LD50 > 1 mg/kg) were spiked into beverages, produce, dairy, and baked goods and assayed using commercially available enzyme-linked immunosorbent assays (ELISAs) and lateral flow devices. In all cases, the commercial diagnostic kits successfully detected all three select agents at concentrations below what might be a health concern. The considerable difference between the limit of detection of the immunodiagnostic devices employed (typically < or = 0.020 microg/g) and the amount of the select agent necessary to pose a health threat in a single serving of food facilitated the design of protocols for the high throughput screening of food samples. These protocols entailed simple extraction methods followed by sample dilution. Lateral flow devices and sandwich ELISAs for the detection of ricin had no significant background problems due to the food matrices. Competitive ELISAs, which typically have unacceptably high background reactions with food samples, successfully detected amanitin and T-2 toxin.

Development of monoclonal antibodies specific forRicinusagglutinins

“…A review of related methodology (Garber, Eppley, Stack, McLaughlin, & Park, 2005) highlighted the significant issues of cross-reactivity and a ''hook effect'' in some assays, including in relatively simple liquid matrices. The hook effect limits rapid screening because it necessitates a dilution series for each sample to be tested.…”

“…This assay has recently been used to estimate the stability of ricin in food matrices (He, Lu, Cheng, Rasooly, & Carter, 2008). In addition to these in vitro assays, mass spectrometric methods for ricin have been developed (Fredriksson et al, 2005;Hines, Brueggemann, & Hale, 2004;Na et al, 2004), and several assays have been commercialised (see Garber et al, 2005;Garber, 2008). Because performance data in complex food matrices is generally lacking and because of our own observations of unacceptable performance of some commercialised methods (unpublished observations), we prepared a panel of mouse monoclonal antibodies (mAbs) to ricin and analysed their performance in sandwich ELISA format.…”

Variability of ricin content in mature seeds of castor bean

“…Several methods, varying in accuracy, facility of use, and time required, allow the detection and quantification of ricin (Garber et al, 2005;Lubelli et al, 2006). The detection of proteins by immunoassays has been widely used in clinical diagnostics and in all areas of biological testing.…”

Detection of ricin toxin in water using immunoassays

“…The major drawbacks were its lengthy incubation time, the problems of handling and disposing of radioisotopes. Enzyme-linked immunosorbent assay (ELISA) is a widely accepted method for the detection of specific proteins [5][6][7][8]. However, the assay time is still too long (46 hours) to meet the requirement of rapidly diagnosing a potential terrorist attack involving a biothreat agent.…”