Daniel Kim
BioE Ph.D. Proposal Presentation
Time and Date: 10:00 am, Wednesday, October 22, 2025
Location: Krone Engineered Biosystems Building, 950 Atlantic Dr NW Suite 1, Atlanta, GA 30332. Room 4029
Zoom Link: https://gatech.zoom.us/j/92359103446
Advisor: Dr. Ravi Kane (Georgia Institute of Technology and Emory University)
Committee Members:
Dr. Anant Paravastu (Georgia Institute of Technology)
Dr. Shuichi Takayama (Georgia Institute of Technology and Emory University)
Dr. Alberto Moreno (Emory University)
Dr. Levi Wood (Georgia Institute of Technology)
Engineering protein-based vaccines and therapeutics
Influenza is a global health concern, causing up to 650,000 deaths worldwide annually despite the availability of seasonal vaccines. Current vaccination strategies and natural infection mainly elicit antibodies against the immunodominant and variable head domain of the hemagglutinin (HA) viral membrane glycoprotein. The antibodies that target this domain are highly neutralizing, but the head domain constantly mutates due to selective pressure and causes the head-directed immune response to be strain-specific. The more conserved stalk domain, however, has shown to be a promising target for the development of a broadly protective influenza vaccine. We introduce two strategies – tethered antigenic suppression and antigenic reorientation – to refocus the immune response towards the conserved stalk domain of HA.
We demonstrate that tethering an antibody fragment to the HA head suppresses antibody responses against all five major antigenic sites on the head while enhancing the induction of anti-stalk antibodies in immunized mice. In addition, in a previous study, we had shown that presenting the HA in an inverted orientation on virus-like particles (VLPs) significantly enhances the induction of stalk-directed, cross-reactive antibodies compared to those elicited by presenting HA in a regular orientation on VLPs. With this promising result, we evaluated the protective efficacy of the inverted H1 HA VLP vaccine (VLP-HAinv) in BALB/cJ mice against homologous, heterologous, and heterosubtypic influenza A virus challenges. The VLP-HAinv vaccination in BALB/cJ mice with various dose regimes provided complete protection against homologous and 2009 pandemic H1N1 heterologous challenges. Moreover, we observed partial protection against a heterosubtypic bovine clade 2.3.4.4b H5N1 virus A/bovine/New Mexico/A240920343-93/2024, a pandemic potential avian influenza strain. We further aim to discover the mechanism of protection elicited by VLP-HAinv by characterizing the Fc-mediated effector functions, T and B cell populations, and the influence of pre-existing immunity.
In addition to designing protein-based vaccines that elicit protective antibodies, we are also interested in identifying target-specific antibodies with possible therapeutic potential. Our focus is on amyloid-β (Aβ) oligomers, increasingly recognized as the most neurotoxic species driving Alzheimer’s disease (AD) pathology. However, their structural and conformational heterogeneity has hindered the development of targeted therapeutics. In this study, we aim to isolate nanobodies with structural selectivity toward a well-defined and homogeneous 150 kDa Aβ oligomer. Preliminarily, we used the Kruse Lab’s yeast surface display nanobody library to perform successive rounds of magnetic-activated cell sorting and fluorescence-activated cell sorting to enrich clones that bind to the 150 kDa Aβ oligomer. We identified nine unique nanobodies, from which four were fused to a human IgG Fc domain to generate bivalent nanobody-Fc constructs. Among these, one nanobody-Fc construct expressed stably in mammalian cells and demonstrated binding to the 150 kDa Aβ oligomer in dot blot assays. However, cross-reactivity with Aβ monomers and fibrils was observed. Future work will incorporate negative selection screens using Aβ monomers to improve the specificity of the nanobody-Fc toward the Aβ oligomers. We will then perform cytokine release and cell viability assays to determine whether the oligomer specific nanobody-Fc can mitigate Aβ oligomer-induced neurotoxicity.