Dr Bin Yang explains how a reagent bank is assisting in the fight against viruses
Viruses are powerful pathogens that have caused several pandemics of diseases and resulted in thousands of deaths as well as economic downturn. As any new viral pathogen emerges, rapid and effective prevention and control are required. Fast development and supply of high-quality biological reagents, such as recombinant proteins, antibodies and kits, are essential for epidemic control and treatment.
A virus is a small parasite that only replicates inside the living cells of an organism. An independent virion usually contains three parts: genetic material; a protein coat; and an external envelope of lipids. During the infection procedure, viruses interact with host cells by the virus surface protein (such as spike protein of SARS-CoV-2) to their corresponding receptors (such as ACE2) for entering into the host cells. Once inside, the virus starts replicating, which depends on their host cell’s protein synthesis pathways. This process will produce abundant copies of viral genomes. Then, the viral proteins are synthesised and assembled. Finally, the newly produced viruses are released from the host cells.
Proteins play an important role in the life cycle of viruses. Virus structural proteins and enzymes are important tools for investigating the pathogenesis of viruses, as well as the targets for the development of vaccines, anti-viral drugs, and diagnostic reagents. With the development in the recombinant protein expression technique, it is now feasible to produce viral proteins in large quantities and use them as tools for a variety of virological researches. For recombinant viral structural protein expression, the eukaryote systems are selected due to their proper post-translational modifications. These proteins include the spike protein of SARS-CoV-2, fusion protein of RSV, fibre protein of ADV, etc. For nonstructural proteins or nucleocapsid proteins of viruses, the E. coli host is a good choice with low cost and fast expression. Representative products include SARS-CoV-2 N protein, other coronavirus N-protein, 3C-like protease, plpro/papain-like protease, etc.
Anti-virus antibodies are core ingredients in serologic tests, therapy development, and vaccine assessments. To obtain highly sensitive antibodies with high specificity, multiple platforms have been exploited, including screening of the existing antibodies. For example, the spike protein and N protein of SARS-CoV share great sequence similarities to those of SARS-CoV-2. When the Covid-19 pandemic broke out, Sino Biological had a quick start by screening its anti-SARS-CoV antibody library and used the SARS-CoV-2 recombinant proteins to remove cross-reactive antibodies and get excellent sensitive and specific candidates for SARS-CoV-2.
Specialist reagent supplier and service provider
Through years of technical accumulation, Sino Biological has well established multiple recombinant protein expression platforms, including bacteria, yeast, baculovirus-insect and mammalian expression systems. With its HEK293-based high-throughput protein/antibody expression platform, hundreds of proteins can be developed simultaneously every week. It has built a large bank of recombinant viral antigens named ProVir, containing over 1,000 products from 90+ virus types/subtypes and almost 400 strains, which features an exclusive SARS-CoV-2 variant antigen bank, a comprehensive influenza vaccine strain antigens collection, and many other hard-to-find viral proteins such as Zika, RSV, Ebola and cytomegalovirus. In addition, it offers 400+ antibodies, 3,000+ genes, and over 900+ other reagents for virological researches and other applications. The viral reagent products are developed and manufactured in accordance with stringent and quality control systems (ISO 9001 and ISO 13485). Their superior properties and biological activity are determined using advanced detection equipment.
The viral reagent products have generated over a thousand citations. For SARS-CoV-2 research citations, there are over 50 articles published in top scientific journals. The core materials for diagnosis of SARS-CoV-2, have been supplied to more than 200 diagnostic companies around the world. Sino Biological is ready for incoming challenges to combat new infectious diseases in the future.
Dr Bin Yang is with Sino Biological