Coronaviruses Vaccine Development

Coronaviruses Vaccine Development

In recent years, emerging viral diseases have become a major global public health threat. The persistent pandemic of coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 has posed a serious public health threat worldwide.

Overview of Coronaviruses

Coronaviruses belong to the subfamily Coronavirinae in the family Coronaviridae of the order Nidovirales and can cause a variety of diseases. Coronavirus can infect humans, birds, domestic animals, mice, bats and many other wild animals, causing lesions in the gastrointestinal tract, respiratory system, liver and central nervous system of susceptible animals.

Classification and Genome of Coronavirus

According to genetic and antigenic characteristics, coronaviruses can be divided into α, β, γ and δ four genera. Wherein, α and β coronavirus only infects mammals, and γ and δ coronavirus mainly infects birds. The coronavirus genome is composed of single-stranded positive-strand RNA ranging from 26 Kb to 32 Kb. It is the virus with the longest genome among known RNA viruses. Its genome includes a 5' cap structure, a 3' polyadenylate tail structure and six open reading frames (ORFs), encoding four major structural proteins and eight auxiliary proteins, which play an important role in the process of virus self-assembly. Coronavirus particles are spherical with a diameter of about 80-160mm.

A typical structure of CoV. (Kirtipal N, et al., 2020)

SARS-CoV-2

SARS-CoV-2 belongs to the genus β coronavirus, which not only causes respiratory discomfort in patients, but also affects the heart, gastrointestinal system, liver, kidneys and central nervous system, eventually leading to multi-organ failure in patients.

The genome of SARS-CoV-2 is approximately 30 K nucleotides in length. The SARS-CoV-2 genome encodes structural proteins (such as the spike protein), nonstructural proteins, and accessory proteins. The four structural proteins of SARS-CoV-2 are considered attractive targets for the development of vaccines and antiviral drugs against the coronavirus, all of which elicit neutralizing antibodies and CD4+/CD8+ T cell responses.

SARS-CoV-2. (Majumder J, et al., 2021)

Why Plants?

"Molecular farming" refers to the use of plants as a platform for the production of diagnostic reagents and pharmaceutical proteins. Plant platforms have the advantages of economy, scalability, and safety because plants can be grown cheaply on a large scale and do not support the growth of human pathogens. In addition, when plant transient expression systems are used, plants can rapidly mass-produce target products to meet sudden and unforeseen needs, especially in the face of rapidly spreading pandemics. Plant platforms are ideal for the production of diagnostic reagents, antiviral drugs and candidate vaccines.

The Applications of Plants for COVID-19 Pandemic. (Capell T, et al., 2020)

Plant-produced VLPs for SARS-CoV-2 Vaccine Candidates

The production of inactivated or attenuated vaccines for SARS-CoV-2 requires sufficient material and such vaccines carry the risk of reversion to virulence of the parental strain. A single protein-based subunit vaccine is a vaccine that is rapidly produced and safe and effective. A number of subunit vaccine candidates have been produced in plants, including several vaccines for seasonal or pandemic strains of influenza produced by transient expression in tobacco. VLPs of SARS-CoV-2 can be generated by different plant platforms because of their size and ordered protein structure that can be efficiently taken up by antigen-presenting cells, triggering the adaptive immune system.

How We Can Help

As an expert in building VLPs from VLPlant^TM platform, CD BioSciences uses its expertise to help our clients develop coronaviruses vaccines. We are good at customizing our services according to the needs of our clients. Please contact us if you are interested.

Our capabilities include but are not limited to:

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References

1. Kirtipal N.; et al. From SARS to SARS-CoV-2, insights on structure, pathogenicity and immunity aspects of pandemic human coronaviruses. Infect Genet Evol. 2021, 85:1-16.
2. Majumder J, Minko T. Recent Developments on Therapeutic and Diagnostic Approaches for COVID-19. AAPS J. 2021, 23:1-22.
3. Capell T.; et al. Huskens J. Potential Applications of Plant Biotechnology against SARS-CoV-2. Trends Plant Sci. 2020, 25:635-643.