Mycobacterium avium paratuberculosis infection augments innate immune responses following intestinal epithelial injury

Abstract

We wanted to determine if augmented innate immune activation is associated with lesion development in a mycobacterial enhanced intestinal injury model. We evaluated the local immune response in a Mycobacterium avium paratuberculosis + dextran sulfate sodium (Map + DSS) model using BALB/c and severe combined immunodeficient (SCID) mice. Map + DSS BALB/c and SCID mice displayed a similar disease phenotype. Moreover, Map + DSS SCID mice had increased expression of interleukin 1β (IL-1β), tumor necrosis factor α (TNF-α), inducible nitric oxide synthase (iNOS) and increased numbers of F4/80 positive cells. Additionally, Map antigen is co-localized with iNOS and IL-1β positive cells. This suggests that subclinical Map infection promotes innate immune activation following injury to the intestinal epithelium.