Assistant Professor
Infectious Diseases
Vision Statement:

My research aims to understand how immune responses in the intestine function in health and disease. This work may lead to better ways to prevent or treat intestinal infections and inflammatory bowel diseases like Crohn’s disease and ulcerative colitis.

Research Interests:

Innate immunity, intestinal epithelial cells, inflammatory bowel disease, C. difficile infection, tropical medicine and international health

Research Sumary:

The intestinal immune system is complex and tightly regulated. It must maintain the ability to respond to dangerous infections while remaining tolerant of the normal, healthy bacteria that line the gut. Failure of this balance leads to severe infections or inflammatory bowel disease. My current research focuses on how intestinal cells respond to a common bacterial protein called flagellin, and how these cells communicate with white blood cells to trigger healthy and unhealthy immune responses.


I play classical piano and cello and sing in Chor Leoni, Canada’s most reknowned men’s choir.

M.D. Duke University 1992
Internal Medicine Duke University 1995
Infectious Diseases University of Virginia 1998.
Recent Publications:
  • Hardenberg G, Yao Y, Piccirillo CA, Levings MK, and Steiner TS. Toll-like receptor 5 deficiency protects from wasting disease in a T cell transfer colitis model in T cell receptor beta deficient mice. Inflamm. Bowel Dis., 2011, in press.
  • Hardenberg G, Steiner TS, and Levings MK. Environmental influences on T regulatory cells in inflammatory bowel disease. Semin Immunol. 2011 Apr;23(2):130-8.
  • Himmel ME, Crome SQ, Ivison SM, Piccirillo C, Steiner TS, and Levings MK. Human CD4+FOXP3+ regulatory T cells produce CXCL8 and recruit neutrophils. Eur J Immunol. 2011 Feb;41(2):306-12.
  • Ivison SM, Himmel ME, Mayer M, Yao Y, Kifayet A, Levings MK, Steiner TS. The stress signal extracellular ATP modulates anti-flagellin immune responses in intestinal epithelial cells. Inflamm Bowel Dis. 2011 Jan;17(1):319-33.
  • Ivison SM, Wang C, Himmel ME, Sheridan J, Delano J, Mayer ML, Yao Y, Kifayet AK, Steiner TS. Oxidative stress enhances IL-8 and inhibits CCL20 production from intestinal epithelial cells in response to bacterial flagellin. Am J Physiol Gastrointest Liver Physiol. 2010 Sep;299(3):G733-41.
  • Steiner TS, Ivison SM, and Kifayet A. Protein kinase D1 and D2 are involved in chemokine release induced by Toll-like receptors 2, 4, and 5. Cell Immunol. 2010;264(2):135-42.
Awards & Recognition:

Burroughs-Wellcome Career Award in Biomedical Sciences; CIHR New Investigator Award