Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/26/2017
Publication Date: 10/9/2017
Publication URL: http://handle.nal.usda.gov/10113/5863576
Citation: Rasooly, R., Do, P.M., Hernlem, B.J. 2017. Interleukin 2 secretion by T cells for detection of biologically active Staphylococcal enterotoxin type E. Journal of Food Protection. 80(11):1857-1862. https://doi.org/10.4315/0362-028X.JFP-17-196.
Interpretive Summary: Staphylococcus aureus bacteria are commonly responsible for food poisonings. Illness is caused by toxins made by the bacteria and it is important to be able to measure the activity of those toxins. Live animals are traditionally used for that purpose but live animal testing is now disfavored. We studied cell based methods for Staphylococcal enterotoxin type E (SEE), a toxin found in foodborne outbreaks in the USA, UK and France. We found a particular molecule, IL-2, is made in large quantities by a Jurkat T-cell line (a kind of immune cell) when presented with SEE in low amounts. The method was specific to SEE and did not respond to similar toxins, SEA and SEB.
Technical Abstract: Staphylococcus aureus is a significant worldwide source of clinical infections and foodborne illnesses acting through the synthesis of a group of enterotoxins (SEs) which cause gastroenteritis and also function as superantigens that activate T cells resulting in massive cytokine production yielding life-threatening toxicity. It is important that methods for detection and quantification of these toxins respond to their activity and not just the presence of the toxin molecule, which may be deactivated. Traditionally, live animals are used to test for emesis following administration of the toxin containing sample. Here we present results studying cell-based alternatives for the assay of active Staphylococcal enterotoxin type E (SEE), a toxin subtype identified in foodborne outbreaks in the USA, UK, and France. We found that IL-2 production by T cells can be used as a specific biological marker for the quantitative detection of SEE as compared with subtypes SEA and SEB. Our assay shows a dose-response relationship between IL-2 secretion by Jurkat T-cell line and SEE concentration as low as 1 pg/mL.