Changseon Choi

Developing innovative therapeutic antibodies and fusion proteins to address the significant clinical unmet needs of rare autoimmune diseases. Responsible for Antibody/Protein Discovery, Engineering, and Non-clinical development.

Dr. Joseph Schlessinger’s lab I assess the therapeutic potency of the engineered FGF21 variant in vitro and in vivo. Evaluated inhibitory efficacy of promising anti-EGFR antibodies screened from structure-guided library. Listed below are some of my highlighted key accomplishments: • Engineering and maturing FGF21 variants for in vivo therapeutic application by introducing fusion proteins. • Characterization of variants using several assays including binding kinetics, cellular activities, and functionality. • Evaluating developed variants in a mouse disease model. • Drafted patent applications for the enhanced therapeutic potential of the engineered FGF21 variants. • Evaluating the inhibitory efficacy of anti-EGFR variant antibodies in vitro.

Dr. Joseph Schlessinger’s lab Engineered FGF21 protein for enhanced activities and determined the structure of an improved FGF21 variant C-tail bound Klotho. Engineered and characterized selected anti-EGFR antibodies and determined the structure of the antibody-EGFR complex. Listed below are some of my highlighted key accomplishments: • Designing and producing engineered FGF ligand chimeras for enhanced FGF21 activity by introducing endocrine and canonical FGF core domains and generating FGF21 C-tail variants for improved binding using the yeast display technology. • Determined the crystal structure of the FGF21 C-tail variant peptide bound to the beta-klotho protein complex, elucidating the improved binding interactions. • Affinity maturation, reformatting anti-EGFR Fab to Full-length IgG, producing and measuring kinetics.

Dr. Bryce Nelson’s Lab Utilized phage display technology to develop novel inhibitory variants against EGFR based on promising inhibitory antibody-bound ErbB3 structure and screened antibodies against many target proteins. Listed below are some of my highlighted key accomplishments: • Phage display selections using naïve libraries against an array of targets. • Designing a structure-guided library using an anti-ErbB3 antibody to screen for variants that bind to the same epitope on EGFR. Designed a bi-specific antibody (ErbB3 and EGFR, with Knobs-into-holes). • Collaborated with multiple research groups to screen high-affinity-binding antibodies against 17 proteins for protein structure determination and functioning as potent inhibitors.

Dr. Priti Kumar’s Lab Conducted an in-depth mechanism study on the intracellular delivery process of ligand-attached siRNA delivery nanoparticles by evaluating efficacy. Orchestrated training sessions on advanced immunological experimental methods while leading a study focused on T-cell research within the context of HIV investigation. Listed below are some of my highlighted key accomplishments: • Uncovered the mechanism of target-specific siRNA delivery nanoparticles using various assays. • Completed BSL-3 safety training by demonstrating proficiency in handling live Bio-Safety Level-3 materials, including the HIV live virus. • Generated HIV-infected humanized mouse models and assessed therapeutic molecules using multi-color flow cytometry. • Designed and optimized siRNA-encapsulated nanoparticles using advanced formulation techniques to enable targeted delivery to specific cells for HIV treatment, utilizing antibodies and peptides as targeting moieties.

In this role, I had the opportunity to translate scientific discoveries into advancements by contributing to development of innovative therapeutic strategies using RNAi technology. In addition, I developed Applying several kinds of siRNA delivery system with target moiety including antibody in mouse disease model for therapeutic applications. Here are some of my highlighted achievements: • Pioneered groundbreaking research in field of RNA Interference nano-medicine targeting HIV viruses. • Translated scientific discoveries into advancements by contributing to development of innovative therapeutic strategies leveraging RNAi technology. • Designed and executed research project focused on developing targeted therapeutic delivery system for rheumatism using macrophage-specific antibodies and siRNA.

Dissertation: Studies on the mechanistic understanding of ligand attached oligo-arginine as a siRNA delivery carrier.

Thesis: Comparison of L, D-isomers of Rvg-9R peptides for efficient siRNA delivery.