Structure-Guided SCHEMA Recombination of VRC01-Class Antibodies for Reduced Polyreactivity

Citation

Gillespie, Sarah Knox (2025) Structure-Guided SCHEMA Recombination of VRC01-Class Antibodies for Reduced Polyreactivity. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/93qk-7n49. https://resolver.caltech.edu/CaltechTHESIS:06022025-062448836

Abstract

The therapeutic administration of monoclonal antibodies (mAbs) has revolutionized treatment options for many diseases over the last decade. Recent findings from clinical trials have demonstrated that broadly neutralizing antibodies (bNAbs) could have a potential role in the future treatment and prevention of HIV-1. There is a group of broad and potent bNAbs that target the CD4-binding site (CD4bs) on the envelope glycoprotein gp120. These VRC01-class antibodies are notable for both their breadth and potency. The Bjorkman lab has designed a remarkably broad and potent bNAb, 45-46m2, that unfortunately cannot currently be used clinically due to its increased polyreactivity and short in vivo half-life. In this study we designed a SCHEMA-guided recombination library composed of sequence fragments of the VRC01-class bNAbs 45-46m2 and 3BNC117, aiming to create a bNAb that is both potent and broad but not polyreactive. We endeavored to maintain the strong binding of 45-46m2 while gaining the low polyreactivity of 3BNC117. Our analysis of this family shuffled library of chimeric antibodies revealed the sequence elements that led to strong binding to gp120 for the chimeras in our library. We also identify three key framework regions that can be modified to significantly reduce polyreactivity. Furthermore, we report three novel chimeras from the family shuffled library that bind as strongly to gp120 as 45-46m2 but are significantly reduced in polyreactivity.

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