Date of Award

Spring 2019

Document Type

Restricted Thesis

Terms of Use

© 2019 Jeffrey O. Zhou. All rights reserved. Access to this work is restricted to users within the Swarthmore College network and may only be used for non-commercial, educational, and research purposes. Sharing with users outside of the Swarthmore College network is expressly prohibited. For all other uses, including reproduction and distribution, please contact the copyright holder.

Degree Name

Bachelor of Arts

Department

Chemistry & Biochemistry

First Advisor

Daniela Fera

Abstract

Understanding affinity maturation of antibodies of great breadth that can target many variants of HIV-1 is important for the development of potential vaccine strategies. To this end, we probed affinity maturation of the CH103 broadly neutralizing antibody (bnAb) clonal lineage using wild-type antigen-binding fragments (Fabs) and I3.2 mutant Fabs. Fabs are derived from the CH103 bnAb lineage, and have mutations found at the interface between the variable heavy chain (V_(H)) and the variable light chain (V_(L)) that likely contributed to the development of breadth. In this lineage, the variable light chain shifted away from gp120 over the course of affinity maturation in order to accommodate insertion mutations in a variable loop, called V5, of the HIV Env, a protein involved in membrane fusion and thus infection. We crystallized mutants to confirm that residues at the V_(H) – V_(L) interface contributed to the shift in orientation. In addition to the V_(H) – V_(L) shift observed, the lineage also had altered stability throughout affinity maturation. The results demonstrate the importance of residues located outside the antigen-binding site in affinity maturation.

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