Virus-like Particles: Fundamentals and Biomedical Applications

Nanotechnology is a fast-evolving field focused on fabricating nanoscale objects for industrial, cosmetic, and therapeutic applications. Virus-like particles (VLPs) are self-assembled nanoparticles whose intrinsic properties, such as heterogeneity, and highly ordered structural organization are exploited to prepare vaccines; imaging agents; construct nanobioreactors; cancer treatment approaches; or deliver drugs, genes, and enzymes. However, depending upon the intrinsic features of the native virus from which they are produced, the therapeutic performance of VLPs can vary. This review compiles the recent scientific literature about the fundamentals of VLPs with biomedical applications. We consulted different databases to present a general scenario about viruses and how VLPs are produced in eukaryotic and prokaryotic cell lines to entrap therapeutic cargo. Moreover, the structural classification, morphology, and methods to functionalize the surface of VLPs are discussed. Finally, different characterization techniques required to examine the size, charge, aggregation, and composition of VLPs are described.

Applications of capillary electrophoresis for biopharmaceutical product characterization

Capillary electrophoresis (CE), after being introduced several decades ago, has carved out a niche for itself in the field of analytical characterization of biopharmaceutical products. It does not only offer fast separation, high resolution in miniaturized format, but equally importantly represents an orthogonal separation mechanism to high-performance liquid chromatography. Therefore, it is not surprising that CE-based methods can be found in all major pharmacopoeias and are recommended for the analysis of biopharmaceutical products during process development, characterization, quality control, and release testing. Different separation formats of CE, such as capillary gel electrophoresis, capillary isoelectric focusing, and capillary zone electrophoresis are widely used for size and charge heterogeneity characterization as well as purity and stability testing of therapeutic proteins. Hyphenation of CE with MS is emerging as a promising bioanalytical tool to assess the primary structure of therapeutic proteins along with any impurities. In this review, we confer the latest developments in capillary electrophoresis, used for the characterization of critical quality attributes of biopharmaceutical products covering the past 6 years (2015-2021). Monoclonal antibodies, due to their significant share in the market, have been given prioritized coverage.

Eastern Equine Encephalitis Virus: A Scoping Review of the Global Evidence

Background: Eastern equine encephalitis virus (EEEV) is a mosquito-borne virus that is primarily found in North America and the Caribbean. Over the past decade there has been an increase in virus activity, including large outbreaks in human and horse populations. Predicted climate change is expected to affect the range of mosquitoes including vectors of EEEV, which may alter disease risk posing a public health concern. Methods: A scoping review (ScR) was conducted to identify and characterize the global evidence on EEEV. A thorough search was conducted in relevant bibliographic databases and government websites. Two reviewers screened titles and abstracts for relevance and the characteristics of relevant articles were extracted using a uniformly implemented data collection form. The study protocol was developed a priori and described the methods and tools used and this article follows the PRISMA-ScR guidelines for reporting ScRs. Results: The ScR included 718 relevant research articles. The majority of the articles originated from North America (97%) between 1933 and 2019. EEEV has been identified in 35 species of mosquitoes, over 200 species of birds, various domestic animals, wild mammals, reptiles, and amphibians. Articles identified in this ScR primarily covered three topic areas: epidemiology of hosts and vectors (344 articles) including surveillance results (138), pathogenesis of EEEV in hosts (193), and in vitro studies characterizing EEEV (111). Fewer articles evaluated the accuracy of diagnostic tests (63), the efficacy of mitigation strategies (62), transmission dynamics (56), treatment of EEEV in hosts (10), societal knowledge, attitudes, and perceptions (4), and economic burden (2). Conclusion: With the projected impact of climate change on mosquito populations, it is expected that the risk of EEEV could change resulting in higher disease burden or spread into previously unaffected areas. Future research efforts should focus on closing some of the important knowledge gaps identified in this ScR.

An Insight into Nanomedicinal Approaches to Combat Viral Zoonoses

BACKGROUND

Emerging viral zoonotic diseases are one of the major obstacles to secure the "One Health" concept under the current scenario. Current prophylactic, diagnostic and therapeutic approaches often associated with certain limitations and thus proved to be insufficient for customizing rapid and efficient combating strategy against the highly transmissible pathogenic infectious agents leading to the disastrous socio-economic outcome. Moreover, most of the viral zoonoses originate from the wildlife and poor knowledge about the global virome database renders it difficult to predict future outbreaks. Thus, alternative management strategy in terms of improved prophylactic vaccines and their delivery systems; rapid and efficient diagnostics and effective targeted therapeutics are the need of the hour.

METHODS

Structured literature search has been performed with specific keywords in bibliographic databases for the accumulation of information regarding current nanomedicine interventions along with standard books for basic virology inputs.

RESULTS

Multi-arrayed applications of nanomedicine have proved to be an effective alternative in all the aspects regarding the prevention, diagnosis, and control of zoonotic viral diseases. The current review is focused to outline the applications of nanomaterials as anti-viral vaccines or vaccine/drug delivery systems, diagnostics and directly acting therapeutic agents in combating the important zoonotic viral diseases in the recent scenario along with their potential benefits, challenges and prospects to design successful control strategies.

CONCLUSION

This review provides significant introspection towards the multi-arrayed applications of nanomedicine to combat several important zoonotic viral diseases.

Four-step approach to efficiently develop capillary gel electrophoresis methods for viral vaccine protein analysis

Vaccines against infectious diseases are urgently needed. Therefore, modern analytical method development should be as efficient as possible to speed up vaccine development. The objectives of the study were to identify critical method parameters (CMPs) and to establish a set of steps to efficiently develop and validate a CE‐SDS method for vaccine protein analysis based on a commercially available gel buffer. The CMPs were obtained from reviewing the literature and testing the effects of gel buffer dilution. A four‐step approach, including two multivariate DoE (design of experiments) steps, was proposed, based on CMPs and was verified by CE‐SDS method development for: (i) the determination of influenza group 1 mini‐hemagglutinin glycoprotein; and (ii) the determination of polio virus particle proteins from an inactivated polio vaccine (IPV). The CMPs for sample preparation were incubation temperature(s) and time(s), pH, and reagent(s) concentration(s), and the detection wavelength. The effects of gel buffer dilution revealed the CMPs for CE‐SDS separation to be the effective length, the gel buffer concentration, and the capillary temperature. The four‐step approach based on the CMPs was efficient for the development of the two CE methods. A four‐step approach to efficiently develop capillary gel electrophoresis methods for viral vaccine protein analysis was successfully established.

Characterization of AEBSF-antibody modifications for a protease inhibitor supplementation strategy

Application of a protease inhibitor, 4-(2-aminoethyl) benzenesulfonyl fluoride (AEBSF), during the cell culture process was demonstrated to effectively reduce proteolytic activity at a specific amino acid site during the production of an HIV-1 broadly neutralizing antibody (bNAb). However, the addition of AEBSF could potentially introduce some modifications to the bNAb protein. Experimental design from sample preparation to LC-MS characterization was performed using middle-up and bottom-up approaches to identify AEBSF-modified species for the bNAb using an AEBSF supplementation in the cell culture media. Modified species along with the unmodified control sample were also subjected to binding activity assessment. The results showed that two amino acids (Tyr177 and Lys250) were susceptible to AEBSF modification in the bNAb test articles but at a negligible level and not in the CDR regions, which therefore did not reduce the in vitro binding activity of the bNAb.

Development of a New Tandem Ion Exchange and Size Exclusion Chromatography Method To Monitor Vaccine Particle Titer in Cell Culture Media

A new tandem chromatography method was developed to directly measure the titers of various vaccine candidate molecules in cell culture without a prior purification step. The method utilized a strong anion exchange chromatography (IEC) column in tandem with a size exclusion chromatography (SEC) column to efficiently separate the nanoparticle and virus-like particle (VLP) vaccine molecules from host cell proteins and other components in the cell culture media. The dual (charge and hydrodynamic size) separation mode was deemed necessary to achieve good separation of the vaccine product for quantitation. The method development and quality assessment illustrated herein was focused on the influenza vaccine candidate H1ssF, a hemagglutinin (group 1) stabilized stem molecule fused to ferritin to form nanoparticles. This newly established method was then successfully applied to several vaccine candidate developmental projects, such as the hemagglutinin-ferritin (HAF) nanoparticle and encephalitic alphavirus VLP-based vaccines. This IEC-SEC strategy was established as a platform approach for direct titer measurement of novel vaccine molecules in cell culture.

Fast, selective and quantitative protein profiling of adenovirus-vector based vaccines by ultra-performance liquid chromatography

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A validated method for quantitative protein profiling in adenovirus-based vaccines.

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14 Adenovirus proteins baseline separated within 17 min by RP-UPLC.

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Adenovirus-based samples directly injected, needing no sample pretreatment.

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The method can detect and quantify protein degradants.

A method for the quantitative determination of the protein composition of adenovirus-vector based vaccines was developed. The final method used RP-UPLC with UV absorbance detection, a C4 column (300 Å, 1.7 μm, 2.1 × 150 mm), and a water- acetonitrile (ACN) gradient containing trifluoroacetic acid (TFA) as ion-pairing agent. The chromatographic resolution between the various adenovirus proteins was optimized by studying the effect of the TFA concentration and the column temperature, applying a full factorial design of experiments. A reproducible baseline separation of all relevant adenovirus proteins could be achieved within 17 min run time. Samples containing adenovirus particles could be directly injected into the UPLC system without sample pretreatment. The viruses reproducibly dissociate into proteins in the UPLC system upon contact with the mobile phase containing ACN. The new RP-UPLC method was successfully validated for protein profiling and relative quantification of proteins in vaccine products based on adenovirus vector types 26 and 35. The intermediate precision of the relative peak areas of all proteins was between 1% and 14% RSD, except for the peak assigned to protein V (26% RSD). The method proved to be stability indicating with respect to thermal and oxidation stress of the adenovirus-vector based vaccine and was successfully implemented for the characterization of adenovirus-based products.

Investigation of Sequence Clipping and Structural Heterogeneity of an HIV Broadly Neutralizing Antibody by a Comprehensive LC-MS Analysis

CAP256 is one of the highly potent, broadly neutralizing monoclonal antibodies (bNAb) designed for HIV-1 therapy. During the process development of one of the constructs, an unexpected product-related impurity was observed via microfluidics gel electrophoresis. A panel of complementary LC-MS analyses was applied for the comprehensive characterization of CAP256 which included the analysis of the intact and reduced protein, the middle-up approach, and a set of complementary peptide mapping techniques and verification of the disulfide bonds. The designed workflow allowed to identify a clip within a protruding acidic loop in the CDR-H3 region of the heavy chain, which can lead to the decrease of bNAb potency. This characterization explained the origin of the additional species reflected by the reducing gel profile. An intra-loop disulfide bond linking the two fragments was identified, which explained why the non-reducing capillary electrophoresis (CE) profile was not affected. The extensive characterization of CAP256 post-translational modifications was performed to investigate a possible cause of CE profile complexity and to illustrate other structural details related to this molecule's biological function. Two sites of the engineered Tyr sulfation were verified in the antigen-binding loop, and pyroglutamate formation was used as a tool for monitoring the extent of antibody clipping. Overall, the comprehensive LC-MS study was crucial to (1) identify the impurity as sequence clipping, (2) pinpoint the clipping location and justify its susceptibility relative to the molecular structure, (3) lead to an upstream process optimization to mitigate product quality risk, and (4) ultimately re-engineer the sequence to be clip-resistant. Graphical Abstract ᅟ.