Justin Bailey
Johns Hopkins University, MD·Microbiology & Immunology
Some people clear a virus on their own, or after a vaccine, while others stay infected for life. The difference often lies in the antibodies and immune cells each person makes, and in which exact piece of the virus those antibodies grab onto.
- Fields
Microbiology & Immunology
Medicine & Clinical Research
Biophysics
- Topics
neutralizing antibodies
bNAbs
hepatitis C virus
- Grants
- 5 known grants, through May 2031
What they work on
- Test whether a dengue vaccine's serotype composition determines the balance, neutralizing potency, and durability of serotype-specific versus cross-reactive memory B cells and monoclonal antibodies, and whether those responses predict protection after controlled human challenge with serotype 2.
- Determine whether vaccine-induced CD4 T cell phenotype and metabolism, particularly expression of glucose transporter 1 (the protein importing sugar fuel into activated cells), support effective B cell and CD8 T cell responses during dengue challenge.
- Profile innate immune cell responses to dengue vaccination and challenge to test whether protective early responses drive stronger CD4 T cell help and cross-reactive antibody production.
- Compare the magnitude and 30-month durability of hepatitis B neutralizing antibodies in people with and without HIV in the MACS-WIHS cohort, using HepG2-NTCP liver cells engineered to carry the HBV entry receptor.
- Isolate B cells binding hepatitis B surface antigen and clone their monoclonal antibodies to test whether those from people who recovered or achieved treatment-induced cure bind more tightly and neutralize more potently than those from people who became chronically infected.
- Define whether HBV-specific B cell frequency, antibody breadth, and T cell function track with hepatitis B cure during nucleos(t)ide analog treatment, using longitudinal blood from cohorts in Uganda, Brazil, India, Senegal, and the United States spanning the major HBV genotypes.
- Isolate broadly neutralizing monoclonal antibodies against the hepatitis C envelope proteins E1 and E2 from Elite Neutralizers who cleared infection spontaneously, and reconstruct their germline ancestors and intermediates by B cell receptor sequencing over time.
- Solve structures of these hepatitis C antibodies bound to soluble E2 or E1E2 by X-ray crystallography or cryo-electron microscopy to identify the envelope features that could be stabilized in a vaccine antigen.
More about the research
Work here centers on reading out those human immune responses in fine molecular detail for three viruses that remain major global problems: dengue virus, hepatitis B virus (HBV), and hepatitis C virus (HCV). A shared toolkit runs across the projects: isolating the rare B cells (the white blood cells that make antibodies) that recognize a given virus, cloning their antibodies one at a time as monoclonal antibodies, testing how strongly those antibodies block infection, and sequencing the B cell receptors to trace how the response matured. The goal is to pin down which responses actually protect, so vaccines and cures can be designed to produce them on purpose.
Why it matters
Dengue, hepatitis B, and hepatitis C together affect hundreds of millions of people, and none has a widely effective vaccine or, for HBV, a cure. By identifying which antibody and T cell responses actually accompany protection or clearance in humans, this work could guide design of a dengue vaccine that avoids worsening disease, inform strategies toward a functional HBV cure including for people also living with HIV, and supply structural blueprints for HCV vaccine antigens.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Analysis of innate responses and vaccination-induced serotype-specific B and T cell responses associated with protection against controlled human dengue virus challenge
NIH · Jun 2026 – May 2031
Immune response dynamics and hepatitis B cure in persons with and without HIV infection
NIH · Sep 2025 – Jul 2030
Molecular and structural characterization of broadly neutralizing anti-HCV antibodies
NIH · Feb 2023 – Jan 2028
Closest labs
Ranjit Ray
Saint Louis University, MO·Microbiology & Immunology
Test whether introducing discrete point mutations into the hepatitis C virus E2 envelope protein, blocking its binding to the cell-surface receptor CD81, prevents E2 from suppressing immune cell function.
David Veesler
University of Washington, WA·Microbiology & Immunology
Characterize how broadly serum antibodies from nonhuman primates immunized with nanoparticle vaccines co-displaying multiple receptor-binding-domain and spike antigens bind and neutralize betacoronaviruses.
Ian Wilson
Weill Medical College of Cornell University, NY·Microbiology & Immunology
Determine how GT1.1-primed antibodies against the CD4 binding site, the pocket HIV uses to grip host cells, recognize shaping and polishing immunogens, using X-ray crystallography, electron microscopy and biophysical analysis of responses from mice, non-human primates and human trial participants.
The school
Johns Hopkins University: 100 labs on PI Pages, $4.1B a year on research, 622 research doctorates a year.
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