Abstract
Staphylococcus aureus is a major bacterial cause of clinical infections and foodborne illnesses through its production of a group of enterotoxins (SEs) which cause gastroenteritis and also function as superantigens to massively activate T cells. In the present study, we tested Staphylococcal enterotoxin type E (SEE), which was detected in 17 of the 38 suspected staphylococcal food poisoning incidents in a British study and was the causative agent in outbreaks in France, UK and USA. The current method for detection of enterotoxin activity is an in vivo monkey or kitten bioassay; however, this expensive procedure has low sensitivity and poor reproducibility, requires many animals, is impractical to test on a large number of samples, and raises ethical concerns with regard to the use of experimental animals. The purpose of this study is to develop rapid sensitive and quantitative bioassays for detection of active SEE. We apply a genetically engineered T cell-line expressing the luciferase reporter gene under the regulation of nuclear factor of activated T-cells response element (NFAT-RE), combined with a Raji B-cell line that presents the SEE-MHC (major histocompatibility complex) class II to the engineered T cell line. Exposure of the above mixed culture to SEE induces differential expression of the luciferase gene and bioluminescence is read out in a dose dependent manner over a 6-log range. The limit of detection of biologically active SEE is 1 fg/mL which is 109 times more sensitive than the monkey and kitten bioassay.
Highlights
The bacterium Staphylococcus aureus is a major cause of clinical infections and foodborne illnesses [1] and produces a range of Staphylococcal Enterotoxins (SEs), twenty-three of which have far been identified
We evaluated an ex vitro assay as an alternative to the monkey and kitten bioassay for measuring biologically active Staphylococcal enterotoxin type E (SEE)
The splenocyte proliferation assay based on BrdU incorporation was applied to measure the effect of SEE concentrations from 10 ng/mL to 1 pg/mL
Summary
The bacterium Staphylococcus aureus is a major cause of clinical infections and foodborne illnesses [1] and produces a range of Staphylococcal Enterotoxins (SEs), twenty-three of which have far been identified. Several SEs subtypes have the potential to pose a severe threat to public health and safety and may be produced as an offensive biologic warfare agent [2]. The SEs target the gastrointestinal tract and behave as superantigens in immune system response. These responses have been shown to be linked [3,4]. SEs bind directly to major histocompatibility complex (MHC) class II of antigen presenting cells (APC) and present them to
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
