Selective immunoglobulin aggregates removal in antivenoms by a simple chromatographic step based on a monolithic stationary phase.

Antivenom therapy is a critical intervention for treating the more than 5.000.000 envenomation accidents that occur each year around the world.

A simple and economic three-step process for producing highly purified Fab' fragments directly from the egg yolk water-soluble fraction.

Although mammals are still the main source of polyclonal antibodies production, the use of egg yolk immunoglobulins (IgY) is increasing, and thus improvement of its safety to reduce undesired reactions is needed. Removal of IgY constant domains by pepsin enzymatic treatment is expected to reduce potential adverse effects derived from the parenteral administration of these antibodies, while also increasing its distribution volume. Current Fab' production requires the previous purification of IgY to be used as starting material.

Immune Maturation Effects on Viral Neutralization and Avidity of Hyperimmunized Equine Anti-SARS-CoV-2 Sera.

Mass-vaccination against COVID-19 is still a distant goal for most low-to-middle income countries. The experience gained through decades producing polyclonal immunotherapeutics (such as antivenoms) in many of those countries is being redirected to develop similar products able to neutralize SARS-CoV-2 infection. In this study we analyzed the biological activity (viral neutralization or NtAb) and immunochemical properties of hyperimmune horses' sera (HHS) obtained during initial immunization (I) and posterior re-immunization (R) cycles using the RBD domain of the SARS-CoV-2 spike protein as antigen.

Peptide Affinity Chromatography Applied to Therapeutic Antibodies Purification.

The interest in therapeutic monoclonal antibodies (mAbs) has significantly grown in the pharmaceutical industry, exceeding 100 FDA mAbs approved. Although the upstream processing of their industrial production has been significantly improved in the last years, the downstream processing still depends on immobilized protein A affinity chromatography. The high cost, low capacity and short half-life of immobilized protein A chromatography matrices, encouraged the design of alternative short-peptide ligands for mAb purification.

Fully Automated Screening of a Combinatorial Library to Avoid False Positives: Application to Tetanus Toxoid Ligand Identification.

Peptide ligands are widely used in protein purification by affinity chromatography. Here, we applied a fully automated two-stage library screening method that avoids false positive peptidyl-bead selection and applied it to tetanus toxoid purification. The first library screening was performed using only sulforhodamine (a fluorescent dye), and fluorescent beads were isolated automatically by flow cytometry and discarded.

Rapid and cost-effective process based on insect larvae for scale-up production of SARS-COV-2 spike protein for serological COVID-19 testing.

Serology testing for COVID-19 is important in evaluating active immune response against SARS-CoV-2, studying the antibody kinetics, and monitoring reinfections with genetic variants and new virus strains, in particular, the duration of antibodies in virus-exposed individuals and vaccine-mediated immunity. In this study, recombinant S protein of SARS-CoV-2 was expressed in Rachiplusia nu, an important agronomic plague. One gram of insect larvae produces an amount of S protein sufficient for 150 determinations in the ELISA method herein developed.

Critical aspects on traditional antivenom production processes and their optimization by factorial analysis.

Most antivenoms are produced by techniques developed over 50 years ago, with minor modifications. Herein we revise the core of traditional antivenom production processes aiming to optimize key determinants for both consistent antivenom production and the best balance between F(ab')2 quality and recovery. Factorial design analysis revealed that pepsin digestion of 1:3 saline diluted equine plasma for 60 min under pH: 3.

Single-step purification of equine chorionic gonadotrophin directly from plasma using affinity chromatography.

Equine chorionic gonadotrophin (eCG) is a hormone widely used in superovulation protocols because of its follicle-stimulating action, which increases reproductive efficiency in animals of productive interest. It contains 45% carbohydrate, 10% of which is N-acetylneuraminic acid (sialic acid). The eCG purification procedures from equine serum or plasma are mainly based on chromatographic methods.

Synthetic peptides to produce antivenoms against the Cys-rich toxins of arachnids.

Scorpion and spider envenomation is treated with the appropriate antivenoms, prepared as described by Césaire Auguste Phisalix and Albert Calmette in 1894. Such treatment requires the acquisition and manipulation of arachnid venoms, both very complicated procedures. Most of the toxins in the venoms of spiders and scorpions are extremely stable cysteine-rich peptide neurotoxins.

Biotechnological potential of Phospholipase D for antivenom development.

Loxoscelism is one of the most important forms of araneism in South America. The Health Authorities from countries with the highest incidence and longer history in registering loxoscelism cases indicate that specific antivenom should be administered during the first hours after the accident, especially in the presence or at risk of the most severe clinical outcome. Current antivenoms are based on immunoglobulins or their fragments, obtained from plasma of hyperimmunized horses.

Use of a phosphopeptide as a ligand to purify phospholipase A from the venom of Crotalus durisuss terrificus by affinity chromatography.

The venom of Crotalus durissus terrificus (Cdt) is a source of a wide variety of toxins, some of them with interesting pharmacological applications. Of these toxins, the phospholipase A (PLA) subunit of crotoxin (Ctx) has been studied for its potential as an antiviral and antibacterial agent. Peptides have proven useful ligands for the purification of numerous molecules, including antibodies, toxins, enzymes and other proteins.

Protocol for bevacizumab purification using Ac-PHQGQHIGVSK-agarose.

Bevacizumab is a monoclonal antibody, produced in CHO cells, used for the treatment of many human cancers. It is an anti-vascular endothelial growth factor (antsi-VEGF) that blocks the growth of tumor blood vessels. Nowadays its purification is achieved by affinity chromatography (AC) using protein A which is a very expensive ligand.

A short peptide fragment of the vascular endothelial growth factor as a novel ligand for bevacizumab purification.

Bevacizumab is a vascular endothelial growth factor (VEGF)-directed monoclonal antibody (mAb) used for the treatment of several human cancers. Given that bevacizumab is administered intravenously, it must have extremely high purity, which is achieved by purification with protein A affinity chromatography (AC). However, protein A is a very expensive ligand, thereby increasing the cost of purification.

Recombinant human follicle stimulating hormone purification by a short peptide affinity chromatography.

Peptide KVPLITVSKAK was selected to design a synthetic ligand for affinity chromatography purification of recombinant human follicle stimulating hormone (rhFSH), based on the interaction of the hormone with the exoloop 3 of its receptor. The peptide was acetylated to improve its stability to degradation by exopeptidases. A cysteine was incorporated at the C-termini to facilitate its immobilization to the chromatographic activated SulfoLink agarose resin.

An effective, simple and low-cost pretreatment for culture clarification in tetanus toxoid production.

Chemically inactivated tetanus toxin (tetanus toxoid, TT), purified from cultures of a virulent Clostridium tetani strain, is the active pharmaceutical ingredient of anti-tetanus vaccines. Culture clarification for TT production and is usually performed by filtration-based techniques. Final clarification of the culture supernatant is achieved by passage through 0.

Single step recombinant human growth hormone (rhGH) purification from milk by peptide affinity chromatography.

Recombinant human growth hormone (rhGH) is used for the treatment of several pathologies, most of them related to growth. Although different expression systems can be used for its production, the milk from transgenic cows is one of the most interesting due to the high rhGH level achieved (5 g/L). We have designed and synthesized short peptides (9 or 10 amino acid long) using Fmoc chemistry and studied their ability to purify rhGH from milk once immobilized on an agarose support.

Natural Snake Venom Inhibitors and their Pharmaceutical Uses: Challenges and Possibilities.

Nowadays, treatment with specific antivenins is considered the only cure for snakebites accidents. However, access to antivenom obstructs the successful implementation of the World Health Organization international guidelines. In the last few years, natural organic compounds, peptides, and proteins with the ability to inhibit snake toxins and obtained from different sources such as plant extracts and animal blood have been proposed as antivenoms.

Sulfanilic acid-modified chitosan mini-spheres and their application for lysozyme purification from egg white.

A cation exchange matrix with zwitterionic and multimodal properties was synthesized by a simple reaction sequence coupling sulfanilic acid to a chitosan based support. The novel chromatographic matrix was physico-chemically characterized by ss-NMR and ζ potential, and its chromatographic performance was evaluated for lysozyme purification from diluted egg white. The maximum adsorption capacity, calculated according to Langmuir adsorption isotherm, was 50.

Simple method to assess stability of immobilized peptide ligands against proteases.

Although peptides are used as affinity chromatography ligands, they could be digested by proteases. Usually, peptide stability is evaluated in solution, which differs from the resin-bounded peptide behavior. Furthermore, the study of the degradation products requires purification steps before analysis.

Affinity chromatography matrices for depletion and purification of casein glycomacropeptide from bovine whey.

Casein glycomacropeptide (CMP) is a 64- amino acid peptide found in cheese whey, which is released after κ-casein specific cleavage by chymosin. CMP lacks aromatic amino acids, a characteristic that makes it usable as a nutritional supplement for people with phenylketonuria. CMP consists of two nonglycosylated isoforms (aCMP A and aCMP B) and its different glycosylated forms (gCMP A and gCMP B).

Combinatorial Library Screening Coupled to Mass Spectrometry to Identify Valuable Cyclic Peptides.

Combinatorial library screening coupled to mass spectrometry (MS) analysis is a practical approach to identify useful peptides. Cyclic peptides can have high biological activity, selectivity, and affinity for target proteins, and high stability against proteolytic degradation. Here we describe two strategies to prepare combinatorial libraries suitable for MS analysis to accelerate the discovery of cyclic peptide structures.

Insect Larvae: A New Platform to Produce Commercial Recombinant Proteins.

In Biotechnology, the expression of recombinant proteins is a constantly growing field and different hosts are used for this purpose. Some valuable proteins cannot be produced using traditional systems. Insects from the order Lepidoptera infected with recombinant baculovirus have appeared as a good choice to express high levels of proteins, especially those with post-translational modifications.

Enhanced antimicrobial activity of a peptide derived from human lysozyme by arylation of its tryptophan residues.

Antimicrobial peptides are valuable agents to fight antibiotic resistance. These amphipatic species display positively charged and hydrophobic amino acids. Here, we enhance the local hydrophobicity of a model peptide derived from human lysozyme (107RKWVWWRNR115) by arylation of its tryptophan (Trp) residues, which renders a positive effect on Staphylococcus aureus and Staphylococcus epidermidis growth inhibition.

Latest Advances in OBOC Peptide Libraries. Improvements in Screening Strategies and Enlarging the Family From Linear to Cyclic Libraries.

Solid phase screenings of one bead one compound (OBOC) libraries have been widely used to find ligands with pharmacological and analytical uses, and to purify or detect proteins in complex mixtures. To improve library screening, in the last years various strategies have been developed to avoid the selection of false positive beads and to obtain selective ligands. Currently, there is great interest in cyclic peptides because of their resistance to enzymatic degradation and higher selectivity compared to their linear counterparts.

A simple protocol for combinatorial cyclic depsipeptide libraries sequencing by matrix-assisted laser desorption/ionisation mass spectrometry.

Short cyclic peptides have a great interest in therapeutic, diagnostic and affinity chromatography applications. The screening of 'one-bead-one-peptide' combinatorial libraries combined with mass spectrometry (MS) is an excellent tool to find peptides with affinity for any target protein. The fragmentation patterns of cyclic peptides are quite more complex than those of their linear counterparts, and the elucidation of the resulting tandem mass spectra is rather more difficult.