8th Annual BMRP Investigator Meeting - Abstract

Isolation of Mycobacterium Avium Subspecies Paratuberculosis Antigen Reactive T-Lymphocytes from Intestinal Biopsies from Crohn’s Patients

¹National Veterinary Institute; ²Centre for Immune Regulation, Institute of Immunology, Rikshospitalet University Hospital (Oslo, Norway); ³ Department of Infectious Disease Immunology, Statens Serum Institut (Copenhagen, Denmark); ⁴ National Animal Disease Center, USDA-Agricultural Research Service (Ames, Iowa, U.S.A.); ⁵Department of Medicine, Rikshospitalet University Hospital (Oslo, Norway)

The role of MAP in Crohn’s disease (CD) remains controversial. One issue that has been raised is the lack of data showing a cellular immune response to MAP. Earlier studies have mostly focused on responses in peripheral blood which have several limitations. We thus wanted to characterize the response in the affected tissue and consequently made T-cell lines from intestinal biopsies of patients with CD (n=11), ulcerative colitis (UC) (n=13) and controls (n=10). The T cells from CD patients showed higher proliferation in response to MAP compared to UC patients (p<0.025), while no differences were detected in response to commensal bacteria. T-cell clones were made from four CD patients and tested for responses to various mycobacterial species. Some T-cell clones responded only to MAP and related mycobacteria in the M. avium complex.The T-cell clones produced IFN-γ and/or IL-17 but minimal amounts of IL-4. The results suggest that MAP or related mycobacteria may contribute to the inflammation in CD.