Presenters: Abigail Johnson
Authors: Abigail Johnson, Hunter Lindsay
Faculty Advisor: Scott Weber
Institution: Brigham Young University
Hypoxanthine-guanine phosphoribosyltransferase (HPRT) is a DNA salvage pathway repair enzyme found intracellularly in all cells that catalyzes the conversion of hypoxanthine to guanine. Recent studies have shown that HPRT is upregulated and expressed on the surface of certain cancers (e.g, prostate and breast cancer), making HPRT a potential biomarker and immunotherapy target. Unique cancer biomarkers are important to initiate an effective cytotoxic therapeutic response against cancer cells. Our goal is to isolate high-affinity antibodies specific for HPRT for use in cancer immunotherapy treatment. From a yeast display library with unique single-chain variable fragment (scFv) antibodies encoded on plasmids we have used MACS and FACS sorting to select 10 clones that have a binding affinity of <10 nM affinity for HPRT. Plasmid isolation and sequencing for each clone will be performed to confirm they are unique and Western blot analysis will be performed to characterize binding affinity and specificity. The scFv will then be placed into a chimeric antigen receptor (CAR) T-cell construct and tested for cytotoxic specificity and efficiency. It will also be configured and tested for antibody dependent cytotoxicity assays. Our research to identify high-affinity scFv antibodies against HPRT could lead to development of effective immunotherapeutic treatments for cancer.