Submitted to: Journal of Environmental and Analytical Toxicology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/16/2017
Publication Date: 11/22/2017
Citation: Rasooly, R., Do, P.M., He, X., Hernlem, B.J. 2017. TCR-Vß8 as alternative to animal testing for quantifying active SEE. Journal of Environmental and Analytical Toxicology. 7(6):527. https://doi.org/10.4172/2161-0525.1000527.
Interpretive Summary: Staphylococcal food poisoning is a result of eating foods contaminated with Staphylococcal enterotoxins (SEs) produced by the bacterium Staphylococcus aureus. Live animals are usually used to detect the form of the toxins that make people sick. For legal and ethical reasons it is better not to use live animals for testing. In this study we used TCR-Vß8, a protein found on the surface of a T cell line as an alternative way to detect Staphylococcal enterotoxin type E (SEE), a toxin found in foodborne outbreaks in the USA, UK and France. Even better is to use fixed dead cells where possible to reduce cell culture work. In this study we show that fixing (killing and preserving) the cells used to present the toxin to the T cells simplifies the method and still allows detection. This method was specific to SEE and did not respond to the related toxin SEB. The assay we developed is a billion times more sensitive than live animal testing.
Technical Abstract: Staphylococcal food poisoning is a result of ingestion of Staphylococcal enterotoxins (SEs) produced by the bacterium Staphylococcus aureus. SEs cause gastroenteritis and also cause activation of T cells and massive cytokine release. A current method for the detection of active SEs relies on its emetic effect on monkeys or kittens. However this costly procedure has low sensitivity and raises ethical concerns. This present study overcomes the limitations of such bioassays by providing an alternative method based on the alteration of TCR Vß8 protein levels expressed on Jurkat T cell-line. We demonstrated that increasing concentrations of SEE, the causative agent in foodborne outbreaks in France, UK and USA, reduced TCR Vß8 protein levels in a dose dependent manner and similarly alters the luciferase gene expression under the regulation of nuclear factor of T-cell activation (NFAT). Unlike previous studies that show accessory cells are not required for T cell activation by SEA or SEB, this present study demonstrated that accessory cells are required for T cell activation by SEE and SEE has greater affinity for the accessory cells than the Jurkat T cell. It is advantageous to use fixed dead cells where possible to reduce cell culture work. In this study we show that fixed accessory cells lacking any metabolic function without processing can present intact SEE and consequently alter TCR Vß8 levels and the reporter gene expression.