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Will Bailis, PhD
Will Bailis
Allen Distinguished Investigator

Dr. Bailis aims to understand how metabolism underlies immunology and disease, by controlling the biochemistry of cells and tissues. His lab does so using in vitro and in vivo CRISPR engineering of primary human and mouse immune cells, with the goal of developing diet and metabolite based therapies.



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Dr. Bailis is an assistant professor of Pathology and Laboratory Medicine at the University of Pennsylvania and Children’s Hospital of Philadelphia. He began his career in science spending his college summers training under Dr. Chioma Okeoma in the laboratory of Dr. Susan Ross, studying viral restriction by APOBEC3. He then received his PhD in immunology from the University of Pennsylvania, where he studied the role of Notch signaling in helper T cell differentiation with Dr. Yumi Ohtani, in the laboratory of Dr. Warren Pear.

After graduating, he joined Dr. Richard Flavell’s research group at Yale University for his postdoctoral fellowship. During his postdoctoral training, he developed in vitro and in vivo primary immune cell CRISPR screening systems to study how cellular metabolism controls immune cell functional programming. His work demonstrated how distinct modes of mitochondrial metabolism and mitochondrial-cytosolic exchange support the unique biochemical demands T lymphocytes must meet at different stages of activation.

Now at Children’s Hospital of Philadelphia, Dr. Bailis continues to explore how metabolism governs cell and tissue behavior, seeking to understand how its dysregulation helps explain disease. The Bailis Lab works to do this by leveraging in vitro and in vivo CRISPR/Cas9 screening systems compatible with gene editing in primary human and mouse immune cells. Together with next generation sequencing and metabolomics, this permits us to fully interrogate how metabolic networks control immune cell function.

Among his career achievements, Dr. Bailis:

  • Demonstrated that helper T cell differentiation and terminal function are biochemically separable
  • Developed a CRISRP screening system compatible with nearly all primary immune cells
  • Elucidated how Notch signaling potentiates multiple helper T cell fates, rather than acting as canonical instructional factor, establishing a novel paradigm for the pathway in the immune system.

Education and Training

BA, Vassar College (Biochemistry), 2008

PhD, University of Pennsylvania (Immunology), 2014

Postdoctoral Fellowship, Yale University School of Medicine (Immunometabolism), 2018

Titles and Academic Titles

Allen Distinguished Investigator

Assistant Professor of Pathology and Laboratory Medicine

Professional Memberships

American Association of Immunologists, 2020-

Society for Leukocyte Biology, 2019-

Professional Awards

Paul Allen Frontiers Group Distinguished Investigator Award, 2020

NIH NIGMS Maximizing Investigators’ Research Award (R35), 2020

NIH NIAID Career Transition Award (K22), 2018

Yale Lung SPORE CDP/DRP Award, 2017

CRI Irvington Postdoctoral Fellowship, 2015

Ruth L. Kirschstein National Research Service Award F31, 2011

Cancer Research Institute Training Award, Cancer Research Institute, 2009

Distinguished Honors, Vassar College, Poughkeepsie, NY, 2008

Oliver M. Lammert Prize, Vassar College, for Excellence In Biochemistry, 2008

Publication Highlights

Bielecki P, Riesenfeld SJ, Hütter JC, Torlai Triglia E, Kowalczyk MS, Ricardo-Gonzalez RR, Lian M, Amezcua Vesely MC, Kroehling L, Xu H, Slyper M, Muus C, Ludwig LS, Christian E, Tao L, Kedaigle AJ, Steach HR, York AG, Skadow MH, Yaghoubi P, Dionne D, Jarret A, McGee HM, Porter CBM, Licona-Limón P, Bailis W, Jackson R, Gagliani N, Gasteiger G, Locksley RM, Regev A, Flavell RA. Skin-resident innate lymphoid cells converge on a pathogenic effector state. Nature. 2021 Apr; 592(7852):128-132. PMID: 33536623
*Harman CCD, *Bailis W (*Equal contribution), Zhao J, Hill L, Qu R, Jackson RP, Shyer JA, Steach HR, Kluger Y, Goff LA, Rinn JL, Williams A, Henao-Mejia J, Flavell RA. An in-vivo screen of noncoding loci reveals that Daedalus is a gatekeeper of a novel Ikaros-dependent checkpoint during haematopoiesis. Proc Natl Acad Sci USA. 2021 Jan; 118(3). PMID: 33446502
Justin A Shyer, Richard A Flavell, Will Bailis. Metabolic signaling in T cells. Cell Res. 2020 Aug; 30(8):649-659. PMID: 32709897
Hao Xu, Theodora Agalioti, Jun Zhao, Babett Steglich, Ramez Wahib, Maria Carolina Amezcua Vesely, Piotr Bielecki, Will Bailis, Ruaidhri Jackson, Daniel Perez, Jakob Izbicki, Paula Licona-Limón, Vesa Kaartinen, Jens Geginat, Enric Esplugues, Eva Tolosa, Samuel Huber, Richard A Flavell, Nicola Gagliani. The induction and function of the anti-inflammatory fate of TH17 cells. Nature Comm. 2020 Jul; 11(1):3334. PMID: 32620760
Bailis W. CRISPR/Cas9 Gene Targeting in Primary Mouse Bone Marrow-Derived Macrophages. Methods Mol Biol. 2020 Jan; 2097:223-230. PMID: 31776929

Active Grants/Contracts

Title: Decoding the 3D immuno-metabolic circuitry

  • Funding Agency: Paul G. Allen Family Foundation
  • Years: 12/11/2020 - 12/11/2023
  • PI: Will Bailis

Title: Examining how the spatial partitioning of metabolism underlies cell state

  • Funding Agency: National Institutes of Health
  • Years: 9/1/2020 - 8/31/2025
  • PI: Will Bailis

Title: Elucidating the molecular mechanisms underlying cellular NAD pool expansion in T lymphocytes

  • Funding Agency: Children's Hospital of Philadelphia Pilot Program
  • Years: 11/1/2019 - 10/31/2021
  • PI: Will Bailis

Title: Elucidating mitochondrial control of nuclear dynamics in the innate immune system

  • Funding Agency: University of Pennsylvania
  • Years: 7/1/2019 - 6/30/2021
  • PI: Will Bailis

Title: The biochemical basis of immune cell reprogramming: how cellular metabolism regulates epigenetic remodeling during T cell differentiation

  • Funding Agency: National Institutes of Health
  • Years: 6/1/2019 - 5/31/2021
  • PI: Will Bailis