@article{barbieri_mollica_moore_sripada_shastry_kilgore_loudermilk_whitacre_kilgour_wuestenhagen_et al._2024, title={Peptide ligands targeting the vesicular stomatitis virus G (VSV-G) protein for the affinity purification of lentivirus particles}, volume={121}, ISSN={["1097-0290"]}, DOI={10.1002/bit.28594}, abstractNote={The recent uptick in the approval of ex vivo cell therapies highlights the relevance of lentivirus (LV) as an enabling viral vector of modern medicine. As labile biologics, however, LVs pose critical challenges to industrial biomanufacturing. In particular, LV purification—currently reliant on filtration and anion‐exchange or size‐exclusion chromatography—suffers from long process times and low yield of transducing particles, which translate into high waiting time and cost to patients. Seeking to improve LV downstream processing, this study introduces peptides targeting the enveloped protein Vesicular stomatitis virus G (VSV‐G) to serve as affinity ligands for the chromatographic purification of LV particles. An ensemble of candidate ligands was initially discovered by implementing a dual‐fluorescence screening technology and a targeted in silico approach designed to identify sequences with high selectivity and tunable affinity. The selected peptides were conjugated on Poros resin and their LV binding‐and‐release performance was optimized by adjusting the flow rate, composition, and pH of the chromatographic buffers. Ligands GKEAAFAA and SRAFVGDADRD were selected for their high product yield (50%–60% of viral genomes; 40%–50% of HT1080 cell‐transducing particles) upon elution in PIPES buffer with 0.65 M NaCl at pH 7.4. The peptide‐based adsorbents also presented remarkable values of binding capacity (up to 3·109 TU per mL of resin, or 5·1011 vp per mL of resin, at the residence time of 1 min) and clearance of host cell proteins (up to a 220‐fold reduction of HEK293 HCPs). Additionally, GKEAAFAA demonstrated high resistance to caustic cleaning‐in‐place (0.5 M NaOH, 30 min) with no observable loss in product yield and quality.}, number={2}, journal={BIOTECHNOLOGY AND BIOENGINEERING}, author={Barbieri, Eduardo and Mollica, Gina N. and Moore, Brandyn D. and Sripada, Sobhana A. and Shastry, Shriarjun and Kilgore, Ryan E. and Loudermilk, Casee M. and Whitacre, Zachary H. and Kilgour, Katie M. and Wuestenhagen, Elena and et al.}, year={2024}, month={Feb}, pages={618–639} }
 @article{prodromou_moore_chu_deal_san miguel_brown_daniele_pozdin_menegatti_2023, title={Molecular Engineering of Cyclic Azobenzene-Peptide Hybrid Ligands for the Purification of Human Blood Factor VIII via Photo-Affinity Chromatography}, volume={1}, ISSN={["1616-3028"]}, url={http://dx.doi.org/10.1002/adfm.202213881}, DOI={10.1002/adfm.202213881}, abstractNote={The use of benign stimuli to control the binding and release of labile biologics for their isolation from complex feedstocks is a key goal of modern biopharmaceutical technology. This study introduces cyclic azobenzene‐peptide (CAP) ligands for the rapid and discrete photo‐responsive capture and release of blood coagulation factor VIII (FVIII). A predictive method—based on amino acid sequence and molecular architecture of CAPs—is developed to correlate the conformation of cis/trans‐CAP photo‐isomers to FVIII binding and release. Combined in silico ‐ in vitro analysis of FVIII:peptide interactions guide the design of a rational approach to optimize isomerization kinetics and biorecognition of CAPs. A photoaffinity adsorbent, prepared by conjugating selected CAP G‐cycloAZOB[Lys‐YYKHLYN‐Lys]‐G on translucent chromatographic beads, features high binding capacity (>6 mg of FVIII per mL of resin) and rapid photo‐isomerization kinetics (τ < 30 s) when exposed to 420–450 nm light at the intensity of 0.1 W cm−2. The adsorbent purifies FVIII from a recombinant harvest using a single mobile phase, affording high product yield (>90%), purity (>95%), and blood clotting activity. The CAPs introduced in this report demonstrate a novel route integrating gentle operational conditions in a rapid and efficient bioprocess for the purification of life‐saving biotherapeutics.}, journal={ADVANCED FUNCTIONAL MATERIALS}, publisher={Wiley}, author={Prodromou, Raphael and Moore, Brandyn David and Chu, Wenning and Deal, Halston and San Miguel, Adriana and Brown, Ashley Carson and Daniele, Michael Angelo-Anthony and Pozdin, Vladimir Aleksandrovich and Menegatti, Stefano}, year={2023}, month={Jan} }
 @article{chu_shastry_barbieri_prodromou_greback-clarke_smith_moore_kilgore_cummings_pancorbo_et al._2023, title={Peptide ligands for the affinity purification of adeno-associated viruses from HEK 293 cell lysates}, volume={7}, ISSN={["1097-0290"]}, DOI={10.1002/bit.28495}, abstractNote={Adeno‐associated viruses (AAVs) are the vector of choice for delivering gene therapies that can cure inherited and acquired diseases. Clinical research on various AAV serotypes significantly increased in recent years alongside regulatory approvals of AAV‐based therapies. The current AAV purification platform hinges on the capture step, for which several affinity resins are commercially available. These adsorbents rely on protein ligands—typically camelid antibodies—that provide high binding capacity and selectivity, but suffer from low biochemical stability and high cost, and impose harsh elution conditions (pH < 3) that can harm the transduction activity of recovered AAVs. Addressing these challenges, this study introduces peptide ligands that selectively capture AAVs and release them under mild conditions (pH = 6.0). The peptide sequences were identified by screening a focused library and modeled in silico against AAV serotypes 2 and 9 (AAV2 and AAV9) to select candidate ligands that target homologous sites at the interface of the VP1‐VP2 and VP2‐VP3 virion proteins with mild binding strength (KD ~ 10−5–10−6 M). Selected peptides were conjugated to Toyopearl resin and evaluated via binding studies against AAV2 and AAV9, demonstrating the ability to target both serotypes with values of dynamic binding capacity (DBC10% > 1013 vp/mL of resin) and product yields (~50%–80%) on par with commercial adsorbents. The peptide‐based adsorbents were finally utilized to purify AAV2 from a HEK 293 cell lysate, affording high recovery (50%–80%), 80‐ to 400‐fold reduction of host cell proteins (HCPs), and high transduction activity (up to 80%) of the purified viruses.}, journal={BIOTECHNOLOGY AND BIOENGINEERING}, author={Chu, Wenning and Shastry, Shriarjun and Barbieri, Eduardo and Prodromou, Raphael and Greback-Clarke, Paul and Smith, Will and Moore, Brandyn and Kilgore, Ryan and Cummings, Christopher and Pancorbo, Jennifer and et al.}, year={2023}, month={Jul} }
 @article{chu_prodromou_moore_elhanafi_kilgore_shastry_menegatti_2022, title={Development of peptide ligands for the purification of a-1 antitrypsin from cell culture fluids}, volume={1679}, ISSN={["1873-3778"]}, DOI={10.1016/j.chroma.2022.463363}, abstractNote={α-1 antitrypsin (AAT) deficiency, a major risk factor for chronic obstructive pulmonary disease, is one of the most prevalent and fatal hereditary diseases. The rising demand of AAT poses a defined need for new processes of AAT manufacturing from recombinant sources. Commercial affinity adsorbents for AAT purification present the intrinsic limitations of protein ligands - chiefly, the high cost and the lability towards the proteases in the feedstocks and the cleaning-in-place utilized in biomanufacturing - which limit their application despite their high capacity and selectivity. This work presents the development of small peptide affinity ligands for the purification of AAT from Chinese hamster ovary (CHO) cell culture harvests. An ensemble of ligand candidates identified via library screening were conjugated on Toyopearl resin and evaluated via experimental and in silico AAT-binding studies. Initial ranking based on equilibrium binding capacity indicated WHAKKSKFG- (12.9 mg of AAT per mL of resin), WHAKKSHFG- (16.3 mg/mL), and KWKHSHKWG- (15.8 mg/mL) Toyopearl resins as top performing adsorbents. Notably, the fitting of adsorption data to Langmuir isotherms concurred with molecular docking and dynamics in returning values of dissociation constant (KD) between 1 - 10 µM. These peptide-based adsorbents were thus selected for AAT purification from CHO fluids, affording values of AAT binding capacity up to 13 gram per liter of resin, and product yield and purity up to 77% and 97%. WHAKKSHFG-Toyopearl resin maintained its purification activity upon 20 consecutive uses, demonstrating its potential for AAT manufacturing from recombinant sources.}, journal={JOURNAL OF CHROMATOGRAPHY A}, author={Chu, Wenning and Prodromou, Raphael and Moore, Brandyn and Elhanafi, Driss and Kilgore, Ryan and Shastry, Shriarjun and Menegatti, Stefano}, year={2022}, month={Aug} }
 @article{chu_prodromou_day_schneible_bacon_bowen_kilgore_catella_moore_mabe_et al._2021, title={Peptides and pseudopeptide ligands: a powerful toolbox for the affinity purification of current and next-generation biotherapeutics}, volume={1635}, ISSN={["1873-3778"]}, DOI={10.1016/j.chroma.2020.461632}, abstractNote={Following the consolidation of therapeutic proteins in the fight against cancer, autoimmune, and neurodegenerative diseases, recent advancements in biochemistry and biotechnology have introduced a host of next-generation biotherapeutics, such as CRISPR-Cas nucleases, stem and car-T cells, and viral vectors for gene therapy. With these drugs entering the clinical pipeline, a new challenge lies ahead: how to manufacture large quantities of high-purity biotherapeutics that meet the growing demand by clinics and biotech companies worldwide. The protein ligands employed by the industry are inadequate to confront this challenge: while featuring high binding affinity and selectivity, these ligands require laborious engineering and expensive manufacturing, are prone to biochemical degradation, and pose safety concerns related to their bacterial origin. Peptides and pseudopeptides make excellent candidates to form a new cohort of ligands for the purification of next-generation biotherapeutics. Peptide-based ligands feature excellent target biorecognition, low or no toxicity and immunogenicity, and can be manufactured affordably at large scale. This work presents a comprehensive and systematic review of the literature on peptide-based ligands and their use in the affinity purification of established and upcoming biological drugs. A comparative analysis is first presented on peptide engineering principles, the development of ligands targeting different biomolecular targets, and the promises and challenges connected to the industrial implementation of peptide ligands. The reviewed literature is organized in (i) conventional (α-)peptides targeting antibodies and other therapeutic proteins, gene therapy products, and therapeutic cells; (ii) cyclic peptides and pseudo-peptides for protein purification and capture of viral and bacterial pathogens; and (iii) the forefront of peptide mimetics, such as β-/γ-peptides, peptoids, foldamers, and stimuli-responsive peptides for advanced processing of biologics.}, journal={JOURNAL OF CHROMATOGRAPHY A}, author={Chu, Wenning and Prodromou, Raphael and Day, Kevin N. and Schneible, John D. and Bacon, Kaitlyn B. and Bowen, John D. and Kilgore, Ryan E. and Catella, Carly M. and Moore, Brandyn D. and Mabe, Matthew D. and et al.}, year={2021}, month={Jan} }