Research — Jo Lab, Hanyang University

Atomic model built into a 2.1 A cryo-EM density map, with individual amino acid side chains resolved — Atomic model built into cryo-EM density at 2.1 Å overall resolution, with individual side chains resolved.

Antibodies are the most direct readout we have of how the immune system sees a pathogen.
Our lab uses single-particle cryo-electron microscopy (cryo-EM) to determine how human antibodies engage the surface antigens of influenza, norovirus and bunyaviruses such as hantaviruses and SFTSV, why a few of those interactions protect broadly across strains, often through molecular features that recur across different individuals¹, and how early exposure imprints and constrains the repertoire that follows^2,3.

We pair this with AI-based protein design, building immunogens that focus the response on conserved, protective epitopes, and testing them in animal models. The elicited antibody response is then analysed structurally, this time at the polyclonal level rather than one antibody at a time, using electron-microscopy-based polyclonal epitope mapping (cryo-EMPEM)^4,5. The resulting epitope landscape defines the specificities an immunogen elicited and guides the next round of design, with the aim of accelerating the vaccine development cycle.

¹ Jo G et al. Nature Communications 16, 7067 (2025)

² Sun J, Jo G et al. Nature 653, 528–537 (2026)

³ Li SH, Wang B et al. Cell Host & Microbe 34, 873–887 (2026)

⁴ Bianchi M et al. Immunity 49, 288–300 (2018)

⁵ Antanasijevic A et al. Nature Communications 12, 4817 (2021)

Directions

Research interests

Broadly neutralizing antibodies — structural definition of the epitopes and binding modes that confer breadth, and of the molecular features that recur in unrelated individuals
Immune imprinting — how an imprinted repertoire evolves with subsequent infection and vaccination, and whether it can be redirected
Polyclonal epitope mapping — cryo-EMPEM of human and animal sera to resolve entire antibody landscapes elicited by infection or immunization
Immunogen design — AI-based protein design of antigens, and of the way they are displayed, to focus the response on conserved epitopes; cryo-EM confirms the target epitope is presented as designed before immunization
Viral inhibitor design — designed binders that block receptor engagement or enzymatic activity on viral surface proteins
Antibody discovery and engineering — phage-displayed libraries and structure-guided optimization toward therapeutic antibodies
Emerging viruses — structural characterization of the surface glycoproteins of hantaviruses and SFTSV, and of the antibody responses they elicit

Background

How we determine a structure

Single-particle cryo-electron microscopy turns a purified sample into an atomic model. The complex is frozen so quickly that the surrounding water never forms ice crystals, and tens of thousands of individual particles are then imaged in random orientations. Combining those images computationally gives a three-dimensional density map detailed enough to trace the protein chain and place individual side chains.

Five steps of a single-particle cryo-EM experiment: sample purification by size-exclusion chromatography, vitrification on a grid, data collection on the microscope, image processing, and building an atomic model into the density map

What we work on

Research interests

How we determine a structure