Date of Award

Spring 2023

Document Type

Restricted Thesis

Terms of Use

© 2023 Molly C. Erdman. 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


Chemistry & Biochemistry Department

First Advisor

Daniela Fera


HIV-1 broadly neutralizing antibodies (bnAbs) are able to neutralize many different circulating strains of HIV-1, making them a desirable target for current vaccine designs. However, these antibodies take many years to develop and can be preceded by cooperating antibodies which develop closer to the onset of infection. These cooperating antibodies target areas on the HIV-1 spike protein (Env) which select for escape mutants that are highly susceptible to neutralization by bnAbs. The goal of this project is to better understand how the cooperating antibody DH272 and the unmutated common ancestor (UCA) of the DH270 bnAb lineage bind to Env and eventually lead to the development of the broadly neutralizing antibody DH270.6 in the CH848 donor that produced these antibodies.

To do this, we used previously determined cryo-EM and crystal structures to create a model of the DH270 UCA1 fab in complex with Env. Using this model and a previously determined model of DH272.2 in complex with Env, we identified 3 UCA1 residues and 4 DH272.2 residues which appeared to be potentially important for binding. These residues were mutated and tested using biolayer interferometry and coelutions to observe their effect on binding. Of the mutants tested, the UCA1 S27YLC mutation and all four DH272.2 mutants showed noticeable changes in binding, indicating that these residues play a role in binding Env. In particular, the UCA1 S27YLC mutation was found to increase UCA1 affinity for Env which could open the door for future structural studies of the DH270 UCAs in complex with Env.