Lay Summary

Proposal No. IBD-0263R
Principal Investigator: Ingrid Olsen, DVM, Ph.D.
Applicant Organization:  Rikshospitalet University Hospital, Oslo University Hospital (Norway)
Project Title:  Isolation of Mycobacterium avium subsp. paratuberculosis antigen reactive T-lymphocytes from intestinal biopsies from Crohn's patients
Period of Award:  May 1, 2009 – April 30, 2011

There are many conflicting theories on the etiology of Crohn’s disease (CD). There is clearly a genetic component and these genetic associations may suggest that Crohn’s disease is triggered by certain bacteria able to live within host cells. One such bacterium is called Mycobacterium avium paratuberculosis (MAP) which causes as similar disease in ruminants. It has been shown that this bacterium is present in CD patients in higher frequencies than control patients. However, it is still not known if it can trigger disease or if it is present without causing any harm. To address this, we plan to isolate immune cells from intestinal samples taken from CD and control patients. These cells are called T-lymphocytes or T cells and contribute to the inflammation in the CD patients by producing certain inflammatory substances. The T cells have two very useful properties; they have memory and they are specific for only one molecule. This means that it is possible to cultivate these T cells in the laboratory and find out if they were triggered by the MAP bacterium or not. We believe that this will provide novel answer to the question whether at least a proportion of CD can be caused by this bacterium.