Development of a Peptidomimetic Ligand for Efficient Isolation and Purification of Factor VIII via Affinity Chromatography

Peptides and pseudopeptide ligands: a powerful toolbox for the affinity purification of current and next-generation biotherapeutics

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.

Regioselective solid-phase synthesis of N-mono-hydroxylated and N-mono-methylated acylpolyamine spider toxins using an 2-(ortho-nitrophenyl)ethanal-modified resin

A recently introduced new SPS resin, possessing a 2-(ortho-nitrophenyl)ethanal linker, was used for the regioselective on-resin synthesis of N-mono-hydroxylated and N-mono-methylated polyamine spider toxins of Agelenopsis aperta and Larinioides folium. The polyamine backbones of the target compounds were efficiently constructed from the center by reductive amination of the aldehyde linker, followed by stepwise alkylation and acylation on solid support. Depending on the cleavage conditions, employing either oxidation/Cope elimination or methylation/Hofmann elimination, regioselectively the respective N-hydroxyl or N-methyl products were obtained. Employing this methodology, a number of acylpolyamine spider toxins were synthesized and identified as venom components by UHPLC and ESI-MS/MS.

Pharmacophoric modifications lead to superpotent αvβ3 integrin ligands with suppressed α5β1 activity

The selective targeting of the αvβ3 integrin subtype without affecting the structurally closely related receptor α5β1 is crucial for understanding the details of their biological and pathological functions and thus of great relevance for diagnostic and therapeutic approaches in cancer treatment. Here, we present the synthesis of highly active RGD peptidomimetics for the αvβ3 integrin with remarkable selectivity against α5β1. Incorporation of a methoxypyridine building block into a ligand scaffold and variation of different functional moieties led to αvβ3-antagonistic activities in the low nanomolar or even subnanomolar range. Furthermore, docking studies were performed to give insights into the binding modes of the novel compounds. The presented library comprises powerful ligands for specific addressing and blocking of the αvβ3 integrin subtype, thereby representing privileged tools for integrin-based personalized medicine.

Production and Purification of Rabbit's Polyclonal Antibody Against Factor VIII

The attempt is made to produce recombinant factor VIII but the first step in producing such product is production and purification of rabbit's polyclonal antibody against factor VIII. The second and third steps involve monoclonal antibody and recombinant factor VIII production. Factor VIII is one of the most important coagulating factor where its deficiency leads to diseases like hemophilia type A or classic. It is an inherited disease. Previously, it was obtained through fractionation of blood plasma of blood donors. After processing, factor VIII could be used to manage such patients. Due to transfer of viral disease like hepatitis and HIV through factor VIII obtained by fractionation, high cost of production, insufficiency of the donors and the process of virus removal, thus production of factor VIII through recombinant technology can be useful and helpful. The reaction between antibody and antigen is one the most specific reaction; therefore, such reaction can be employed to identify factor VIII. Thereby, rabbits were injected several times with adjuvant-linked antigen to produce antibody. The antibody was separated from the blood sample, purified and used to identify factor VIII in the research.