Designing a Minimally Mutated Antibody that Maintains Breadth and Potency Against HIV

Although HIV is no longer a headline issue in the media, over 39 million people worldwide are still living with the virus, with more than a million new infections each year. Despite significant advancements in therapeutic treatments, the development of a preventative vaccine remains critical for global HIV control. Current vaccine design strategies focus on eliciting broadly neutralizing antibodies (bNAbs) that can neutralize a wide range of HIV strains. SF10 is one such bNAb; however, the mature antibody contains many mutations relative to its germline precursor, which are essential for its functionality. Understanding which of these mutations are necessary for HIV neutralization and breadth have the potential to inform immunogen design. Here, I generated a yeast library containing individual clones that reverted non-paratope contacts to the germline-encoded amino acid for SF10. Clones that enriched for binding to gp120, a key protein critical for HIV’s cell entry mechanism, were selected by flow cytometry and subsequently cloned. ELISA and Biolayer Interferometry (BLI) were used to measure the binding of these mutated antibodies to cross-clade HIV gp120 monomers. Furthermore, I performed neutralization assays to confirm that antibody binding resulted in effective viral neutralization. My findings identified a minimally mutated version of SF10, with just 18 mutations in the heavy chain compared to its germline form, which retains broad neutralization and potency against a diverse panel of HIV isolates. These results provide valuable insight into the critical mutations required for SF10 to neutralize HIV, highlighting the key targets for future HIV vaccine immunogen design.