A recently published study has found some evidence that enterohaemorrhagic E.coli(EHEC) may be able to evade or suppress our immune system.

Scanning electron micrograph showing EHEC (red) adhering to human intestinal biopsy epithelium. Image by Steven Lewis and Stephanie Schüller

EHEC (aka E. coli O157) causes around 1200 cases of food poisoning in the UK every year. Symptoms are serious, ranging from diarrhoea to acute kidney failure and neurological damage. Outbreaks can be hard to trace; one current outbreak has affected over 100 people but the exact source has yet to be identified. EHEC is a particular problem as there is currently no treatment.

To help address this, Dr Stephanie Schüller from the Institute of Food Research and the Norwich Medical School at the University of East Anglia is leading a team of researchers studying how EHEC, causes disease in our body.

Previous work by PhD student Steven Lewis working with colleagues at the Gastroenterology Department of the Norfolk and Norwich University Hospital has shown that EHEC attaches itself to the lining of the colon, where it persists and triggers the serious symptoms associated with infection. In this subsequent study, the researchers were interested to see how the lining of the colon, which provides the first line of defence of our immune system, responded to EHEC infection.

The research team now want to understand how EHEC avoids triggering a full immune response, which will add to our understanding of this serious pathogen, and may point to new ways of combatting its effects.

This study was supported by the University of East Anglia, the Biotechnology and Biological Sciences Research Council, the National Institute for Health Research and the Medical Research Council.

Unexpectedly, we found that EHEC infection induced a weak innate immune response and only triggered the release of few antimicrobial proteins that would normally have been seen as the immune system attempts to combat pathogenic bacteria.

Dr Stephanie Schüller

Read more about this study in this article by Dr Stephanie Schüller on the IFR Gut Health and Food Safety programme blog.

Reference Flagellin Induces β-Defensin 2 in Human Colonic Ex vivo Infection with Enterohemorrhagic Escherichia coli, Steven B. Lewis, Alison Prior, Samuel J. Ellis, Vivienne Cook, Simon S. M. Chan, William Gelson and Stephanie Schüller, Frontiers in Cellular and Infection Microbiology doi: 10.3389/fcimb.2016.00068