Improved Expression of SARS-CoV-2 Spike RBD Using the Insect Cell-Baculovirus System.

Insect cell-baculovirus expression vector system is one of the most established platforms to produce biological products, and it plays a fundamental role in the context of COVID-19 emergency, providing recombinant proteins for treatment, diagnosis, and prevention. SARS-CoV-2 infection is mediated by the interaction of the spike glycoprotein trimer via its receptor-binding domain (RBD) with the host's cellular receptor. As RBD is required for many applications, in the context of pandemic it is important to meet the challenge of producing a high amount of recombinant RBD (rRBD).

Novel bridge multi-species ELISA for detection of SARS-CoV-2 antibodies.

Unlabelled: Considering the course of the current SARS-CoV-2 pandemic, it is important to have serological tests for monitoring humoral immune response against SARS-CoV-2 infection and vaccination. Herein we describe a novel bridge enzyme-linked immunosorbent assay (b-ELISA) for SARS-CoV-2 antibodies detection in human and other species, employing recombinant Spike protein as a unique antigen, which is produced at high scale in insect larvae.

Methods: Eighty two human control sera/plasmas and 169 COVID-19 patients' sera/plasmas, confirmed by rRT-PCR, were analyzed by the b-ELISA assay.

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.

Supramolecular effect of acetate on chitin gelling medium: Structural properties and protein interaction.

In this work, the influence of Sodium Acetate Trihydrate (SAT) on the gelling stage of a chitin hydrogel was studied. Characterization techniques, such as FTIR, Raman, solid-state NMR, Dielectric Spectroscopy, Small-angle X-ray scattering (SAXS), Wide-angle X-ray scattering (WAXS), and X-ray diffraction (XRD) were used to study the effect of SAT on the micro and nanostructure of the material in the wet, dry and freeze-dried states. It was demonstrated that the amount of SAT in the gelling solution can induce a variation in the supramolecular interaction among the polysaccharide chains, which leads to a change in the structural characteristics.

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.

Production of biologically active feline interferon beta in insect larvae using a recombinant baculovirus.

Feline interferon beta is a cytokine that belongs to the type I IFN family, with antitumor, antiviral and immunomodulatory functions. In this work, recombinant feline interferon beta (rFeIFNβ) was expressed in insect larvae that constitute important agronomic plagues. rFeIFNβ accumulated in the hemolymph of larvae infected with recombinant baculovirus and was purified by Blue-Sepharose chromatography directly from larval homogenates on day 4 post-infection.

Bovine lactoferrin purification from whey using Yellow HE-4R as the chromatographic affinity ligand.

The worldwide production of whey increases by around 186 million tons each year and it is generally considered as a waste, even when several whey proteins have important economic relevance. For its valorization, inexpensive ligands and integrated chromatography methods need to be developed for specific and low-cost protein purification. Here, we describe a novel affinity process with the dye Yellow HE-4R immobilized on Sepharose for bovine lactoferrin purification.

Rachiplusia nu larva as a biofactory to achieve high level expression of horseradish peroxidase.

A process based on orally-infected Rachiplusia nu larvae as biological factories for expression and one-step purification of horseradish peroxidase isozyme C (HRP-C) is described. The process allows obtaining high levels of pure HRP-C by membrane chromatography purification. The introduction of the partial polyhedrin homology sequence element in the target gene increased HRP-C expression level by 2.