Toxicologie environnementale et analytique

TCR-Vβ8 as Alternative to Animal Testing for Quantifying Active SEE

Abstract

Reuven Rasooly, Paula Do, Xiaohua He and Bradley Hernlem

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 Vβ8 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 Vβ8 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 Vβ8 levels and the reporter gene expression.