Dietary Antigen‐Specific T‐Cell Responses: Switch from an Interleukin‐10‐Dominated Response in Normal Mice to a T‐Helper 1 Cytokine Profile in Gαi2‐Deficient Mice prior to Colitis

• Published in: Scandinavian journal of immunology 2005-01, Vol.61 (1), p.29-35
• Main Authors: Bjursten, M., Hultgren Hörnquist, E.
• Format: Article
• Language: English
• ISSN: 0300-9475; 1365-3083
• DOI: 10.1111/j.0300-9475.2005.01535.x

We investigated dietary antigen‐specific T‐cell responses in mesenteric lymph nodes (MLN) and Peyer's patches (PP) in noncolitic control mice as well as in colitis‐prone mice prior to onset of histological active colitis. T cells were restimulated in vitro with constituents isolated from the mouse diet. Interestingly, MLN T cells of littermate Gαi2+/– control mice responded to soya with high production of interleukin (IL)‐10, but did not produce proinflammatory T‐helper 1 (Th1) cytokines. Recall dietary antigen stimulation of Gαi2+/– PP T cells did not result in increased IL‐10 production above the spontaneous production in the absence of antigenic stimulation. In strong contrast, MLN T cells from precolitic Gαi2–/– mice produced high levels of interferon‐gamma (IFN‐γ) upon restimulation with soya, which could be abolished using a major histocompatibility complex class II‐blocking antibody. In conclusion, the present study demonstrates that MLN T lymphocytes in normal healthy mice respond with a significantly increased production of the regulatory cytokine IL‐10 on re‐encounter with dietary proteins in vitro. In marked contrast precolitic Gαi2–/– mice respond to dietary antigens with a Th1‐dominated cytokine response in the mucosa, prior to onset of colitis, with excessive IFN‐γ production. These results suggest that aberrant immune responses to dietary antigens could contribute as a potential pathogenic mechanism in the onset of colitis in Gαi2‐deficient mice.