Megan T. Baldridge, M.D., Ph.D.

Assistant Professor
Internal Medicine
Infectious Diseases
Molecular Microbiology

Molecular Microbiology and Microbial Pathogenesis Program
Molecular Genetics and Genomics Program
Immunology Program
Computational and Systems Biology Program

  • 314-273-1212

  • 314-273-1220

  • 832-236-4899

  • 8510

  • Room 4204, McKinley Research Building, 4515 McKinley McKinley Ave, St. Louis, MO 63110



  • microbiota, infection, pathogen, microbiome, virus, interferon, immunity

  • Defining the mechanisms behind and effects of the interactions between commensal bacteria, pathogens and innate immunity

Research Abstract:

The Baldridge lab is broadly interested in the complicated interplay between three important factors: commensal microbes, the host immune system, and viral and bacterial pathogens. Previous work has involved characterization of the intestinal commensal microbiota and interrogation of its role in regulation of both enteric viral infection and the host immune system. The coordination of next-generation sequencing efforts with in vivo infections and treatments in mouse models makes the exploration of transkingdom interactions possible. There are several main areas the Baldridge lab is currently pursuing:

1. Determine the cellular source of the inflammatory cytokine interferon-lambda (IFN-λ) in the intestine induced by commensal bacteria and by pathogens, and the signaling pathways and transcription factors that regulate its expression.
2. Define specific commensal bacteria necessary and sufficient to enhance and regulate viral infection in the intestine.
3. Explore viral adaptation strategies to take advantage of commensal microbes and to infect at alternate host sites.
4. Understand how interactions between bacteria and bacteriophage may contribute to microbiota development and disease.

Selected Publications:

Bennion BG, Ingle H, Ai TL, Miner CA, Platt DJ, Smith AM, Baldridge MT#, Miner JJ# (2019). A human gain-of-function STING mutation causes immunodeficiency and gammaherpesvirus-induced pulmonary fibrosis in mice. Journal of Virology. pii: JVI.01806-18. #co-corresponding

Wilen CB, Lee S, Hsieh LL, Orchard RC, Desai C, Hykes BL Jr, McAllaster MR, Balce DR, Feehley T, Brestoff JR, Hickey CA, Yokoyama CC, Wang YT, MacDuff DA, Kreamalmayer D, Howitt MR, Neil JA, Cadwell K, Allen PM, Handley SA, van Lookeren Campagne M, Baldridge MT, Virgin HW (2018). Tropism for tuft cells determines immune promotion of norovirus pathogenesis. Science. 360(6385):204-208.

Lee S, Wilen CB, Orvedahl A, McCune BT, Kim K, Orchard RC, Peterson ST, Nice TJ, Baldridge MT#, Virgin HW# (2017). Norovirus Cell Tropism is Determined by Combinatorial Action of a Viral Non-structural Protein and Host Cytokine. Cell Host & Microbe. 22(4):449-459. #co-corresponding

Baldridge MT*, Lee S*, Brown JJ, McAllister N, Urbanek K, Dermody TS, Nice TJ, Virgin HW (2017). Expression of Ifnlr1 on intestinal epithelial cells is critical to the antiviral effects of IFN-lambda against norovirus and reovirus. Journal of Virology. 13;91(7). * equal contribution

Josefsdottir KS, Baldridge MT, Kadmon CS, King KY (2016). Antibiotics impair murine hematopoiesis by depleting intestinal microbiota. Blood. pii: blood-2016-03-708594.

Moon C*, Baldridge MT*, Wallace MA, Burnham CD, Virgin HW, Stappenbeck TS. (2015). Vertically transmitted faecal IgA levels determine extra-chromosomal phenotypic variation. Nature, 521(7550):90-3. * equal contribution

Baldridge MT, Nice TJ, McCune BT, Yokoyama C, Kambal A, Wheadon M, Lazear HM, Diamond MS, Ivanova Y, Artyomov M, Virgin HW. (2015). Commensal microbes and interferon-λ determine persistence off enteric murine norovirus infection. Science, 347(6219):266-9.

Nice TJ, Baldridge MT, McCune BT, Norman JM, Lazear HM, Artyomov M, Diamond MS, Virgin HW. (2015). Interferon λ cures persistent murine norovirus infection in the absence of adaptive immunity. Science, 347(6219):269-73.

Norman JM*, Handley SA*, Baldridge MT, Droit L, Liu CY, Keller BC, Kambal A, Monaco CL, Zhao G, Fleshner P, Stappenbeck TS, McGovern DP, Keshavarzian A, Mutlu EA, Sauk J, Gevers D, Xavier RJ, Wang D, Parkes M, Virgin HW. (2015). Disease-Specific Alterations in the Enteric Virome in Inflammatory Bowel Disease. Cell, 160(3):447-60. * denotes equal contribution

Baldridge MT*, King KY*, Boles NC, Weksberg DC, and Goodell MA. Quiescent hematopoietic stem cells are activated by IFN-gamma in response to chronic infection. (2010). Nature, 465: 793-797. * denotes equal contribution

Last Updated: 1/3/2019 1:10:43 PM

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