Humanization of Yeasts for Glycan-Type End-Products

Production of biologically active recombinant salmon calcitonin in Escherichia coli and fish cell line

Salmon calcitonin is a small peptide hormone synthesised and released by a specialised gland called ultimobranchial gland in fish. This hormone has been used to treat osteoporosis for over 50 years. The aim of this study was to compare the efficacy of five repeats of salmon calcitonin (5sCT) produced in two different hosts (bacteria and fish cell line). The 5sCT gene was synthesised and cloned in prokaryotic (pET32b(+)) and eukaryotic (pcDNA 3.1 + and pGenlenti) vectors. The pET32 b cloned plasmid was transformed into bacterial host BL 21 (DE3) and expression of recombinant 5sCT was induced by IPTG. The 5sCT cloned pcDNA 3.1 and pGenlenti plasmids were transfected using Lipofectamine 3000 in snubnose pompano fin (SPF) cell line. The expression of recombinant 5sCT protein in both hosts was confirmed by Western blot and ELISA using a polyclonal antibody raised against r-5sCT in mice. The results of Western blot and ELISA confirmed the expression of 5sCT protein in E. coli and SPF cells. The purified r-5cST expressed from both hosts was evaluated in mice via intramuscular injection at various dosages, and it was found that it significantly decreased serum calcium levels in mice when compared to normal mice.

Protein Expression Platforms and the Challenges of Viral Antigen Production

Several protein expression platforms exist for a wide variety of biopharmaceutical needs. A substantial proportion of research and development into protein expression platforms and their optimization since the mid-1900s is a result of the production of viral antigens for use in subunit vaccine research. This review discusses the seven most popular forms of expression systems used in the past decade-bacterial, insect, mammalian, yeast, algal, plant and cell-free systems-in terms of advantages, uses and limitations for viral antigen production in the context of subunit vaccine research. Post-translational modifications, immunogenicity, efficacy, complexity, scalability and the cost of production are major points discussed. Examples of licenced and experimental vaccines are included along with images which summarize the processes involved.

Multifaceted virus-like particles: Navigating towards broadly effective influenza A virus vaccines

The threat of influenza A virus (IAV) remains an annual health concern, as almost 500,000 people die each year due to the seasonal flu. Current flu vaccines are highly dependent on embryonated chicken eggs for production, which is time consuming and costly. These vaccines only confer moderate protections in elderly people, and they lack cross-protectivity; thereby requiring annual reformulation to ensure effectiveness against contemporary circulating strains. To address current limitations, new strategies are being sought, with great emphasis given on exploiting IAV's conserved antigens for vaccine development, and by using different vaccine technologies to enhance immunogenicity and expedite vaccine production. Among these technologies, there are growing pre-clinical and clinical studies involving virus-like particles (VLPs), as they are capable to display multiple conserved IAV antigens and augment their immune responses. In this review, we outline recent findings involving broadly effective IAV antigens and strategies to display these antigens on VLPs. Current production systems for IAV VLP vaccines are comprehensively reviewed. Pain-free methods for administration of IAV VLP vaccines through intranasal and transdermal routes, as well as the mechanisms in stimulating immune responses are discussed in detail. The future perspectives of VLPs in IAV vaccine development are discussed, particularly concerning their potentials in overcoming current immunological limitations of IAV vaccines, and their inherent advantages in exploring intranasal vaccination studies. We also propose avenues to expedite VLP vaccine production, as we envision that there will be more clinical trials involving IAV VLP vaccines, leading to commercialization of these vaccines in the near future.

Precise Therapy Using the Selective Endogenous Encapsidation for Cellular Delivery Vector System

Interindividual variability in drug response is a major problem in the prescription of pharmacological treatments. The therapeutic effect of drugs can be influenced by human genes. Pharmacogenomic guidelines for individualization of treatment have been validated and used for conventional dosage forms. However, drugs can often target non-specific areas and produce both desired and undesired pharmacological effects. The use of nanoparticles, liposomes, or other available forms for drug formulation could help to overcome the latter problem. Virus-like particles based on retroviruses could be a potential envelope for safe and efficient drug formulations. Human endogenous retroviruses would make it possible to overcome the host immune response and deliver drugs to the desired target. PEG10 is a promising candidate that can bind to mRNA because it is secreted like an enveloped virus-like extracellular vesicle. PEG10 is a retrotransposon-derived gene that has been domesticated. Therefore, formulations with PEG10 may have a lower immunogenicity. The use of existing knowledge can lead to the development of suitable drug formulations for the precise treatment of individual diseases.

Impact of PpSpi1, a glycosylphosphatidylinositol-anchored cell wall glycoprotein, on cell wall defects of N-glycosylation-engineered Pichia pastoris

IMPORTANCE

Engineering of biological pathways in various microorganisms is a promising direction for biotechnology. Since the existing microbial cells have evolved over a long period of time, any artificial engineering may cause some unexpected and harmful effects on them. Systematically studying and evaluating these engineered strains are very important and necessary. In order to produce therapeutic proteins with human-like N-glycan structures, much progress has been achieved toward the humanization of N-glycosylation pathways in yeasts. The properties of a P. pastoris strain with humanized N-glycosylation machinery were carefully evaluated in this study. Our work has identified a key glycoprotein (PpSpi1) responsible for the poor growth and morphological defects of this glycoengineered strain. Overexpression of PpSpi1 could significantly rescue the growth defect of the glycoengineered P. pastoris and facilitate its future industrial applications.