(608a) Novel High-Throughput Technology for Antibody Discovery Synthesizing the Virion Display and Yeast Display Platforms

G-protein coupled receptors (GPCRs) are a class of seven-pass transmembrane (TM) proteins that mediate physiological responses to a vast array of environmental cues such as hormones, neurotransmitters, and sensory stimuli, and therefore have great potential as therapeutic targets for a broad spectrum of diseases. However, membrane proteins, especially those containing multiple TM domains, are notoriously difficult to study because they must be embedded in a lipid membrane to maintain their native conformations, and because they require post-translational modifications, which only occur during transport in the cellular secretory pathway. The recently developed virion display (VirD) system successfully presented over 315 non-odorant human GPCRs on the envelopes of engineered herpes simplex virus (HSV)-1 virions and demonstrated that they maintained their native conformations, with properly folded TM domains and canonical PTMs. This exciting development enables the design of a high-throughput platform for the discovery of specific binders to the extracellular domains of GPCRs in their biologically relevant orientations, which can be used to probe downstream signaling and to potentially bias receptor activities for therapeutic ends.

Human antibodies are of particular interest as therapeutics because of their high specificity, multi-faceted mechanisms of action, favorable pharmacokinetic properties, and reduced immunogenicity compared to small molecule drugs. To harness the VirD platform for high-throughput discovery of antibody drugs, a rapid and cost-effective display platform for antibodies is needed. The yeast surface display platform provides such an evolutionary engine, due to the ease of yeast cell culturing and the availability of protein folding and post-translational machinery capable of handling complex mammalian proteins.

We have integrated the VirD system with yeast surface display to create a novel platform for discovery of antibodies targeting membrane proteins, with a particular focus on GPCRs. The performance of our new selection system compares favorably to other screening methods and has several advantages, including (i) rapid evolutionary workflow; (ii) no requirement for soluble expression of membrane proteins; (iii) appropriate presentation of target antigen; and (iv) compatibility with high-throughput screening. Overall, our innovative engineering platform presents a powerful methodology for isolating anti-GPCR antibodies that can be used both as research tools and medical interventions. Use of our technology will help elucidate the molecular determinants of GPCR signaling and inform the design of targeted proteins for a wide range of therapeutic applications, including cancer, infectious diseases, and neurological disorders.