mRNA Vaccines and mRNA Technology

mRNA Vaccines and mRNA Technology: An Introduction

An RNA vaccine or mRNA vaccine is an emerging type of vaccine based on mRNA technology. The working principle centers on inducing acquired immunity using a vector containing an RNA sequence that would code for proteins similar to those of a specific pathogen.

Explaining Vaccine Development Based on mRNA Technology

What is mRNA Technology? What are RNA Vaccines?

Messenger RNA or mRNA technology corresponds to medical and therapeutic approaches based on the idea of teaching cells to produce substances that could treat or prevent diseases. Examples of these substances include enzymes that could rid the body of toxins, antibodies that would confer immunity against pathogens, or growth factors for tissue repair.

Take note that an mRNA is a single-stranded RNA molecule that relays genetic instructions from the DNA to the protein-making component of cells called ribosomes. By re-engineering an mRNA to relay a specific set of instructions, specific proteins could be deliberately produced, thereby turning cells into medicine-making factories.

mRNA vaccines are based on the aforementioned principle. Specifically, the RNA sequence contained therein serves as a template for building a protein identical or resembling a pathogen.  Once introduced to the body, the host cells produce this protein that, in turn, would be recognized by the immune system and result in the production of antibodies for an adaptive immune response against a specific pathogen.

It is important to highlight the fact that vaccines generally work by training the immune system to recognize and responds to the proteins of pathogenic organisms such as viruses and bacteria. Conventional vaccines are made from a small load of a pathogen, a weakened or inactivated counterpart, its toxins, or the proteins it produces.

However, an mRNA vaccine tricks the body to produce the protein of this pathogen itself. Vaccine development using mRNA technology involves producing a synthetic version of the mRNA that a pathogen uses to build its proteins. Because the mRNA is engineered in the laboratory, developers can provide instructions for the production of independent proteins incapable of reproduction or assembling into a virus.

What are the Advantages and Disadvantages of mRNA Vaccines?

There are no mRNA vaccines approved for human use. However, since the COVID-19 pandemic, several biotech companies have designed and tested candidate vaccines using mRNA technology to provide the global population with immunity against SARS-CoV-2 and the corresponding coronavirus disease. The phase at which these vaccines are undergoing development has remained remarkable.

One of the advantages of mRNA vaccines over conventional vaccines, including DNA vaccines, is that they shorten the stages of vaccine development because they accelerate immunogen discovery. They are also easier and faster to produce. Hence, they also address some of the challenges in developing a vaccine.

mRNA technology is also flexible. An mRNA can encode and express any protein. Diverse vaccine candidates can be manufactured using the same process with minimal to zero adjustments, thus reducing cost and lessening the lead time of development.

They also possess the same benefits of DNA vaccines. However, it is considerably straightforward. DNA vaccines need to overcome the cytoplasmic membrane and nuclear membrane, be transcribed into mRNA, and move back into the cytoplasm and initiate translation.

An outstanding safety profile is another advantage of mRNA vaccines. They are intrinsically safe because they are essentially minimal and transient carriers of genetic information that does not interact with the genome. Note that they only consist of an RNA sequence needed for the expression of the encoded protein. They also decay metabolically within a few days.

There are some disadvantages and challenges, of course. The overall technology is considerably novel, and many questions could only be answered through clinical trials. In terms of vaccines, the primary point of inquiry focuses on whether mRNA vaccines could confer sufficient and long-term immune response and protection.

It is also essential to determine the most suitable protein. A candidate vaccine could stimulate an unintended immune response, thus requiring developers to design RNA sequences that mimic those produce by the intended host cells. Another concern revolves around the possibility of triggering adverse immune reactions such as inflammation and autoimmunity.

FURTHER READINGS AND REFERENCES

  • Jackson, N. A. C., Kester, K. E., Casimiro, D., Gurunathan, S., and DeRosa, F. 2020. “The Promise of mRNA Vaccines: A Biotech and Industrial Perspective.” NPJ Vaccines. 5(11). DOI: 1038/s41541-020-0159-8
  • Konsyse. 2019. The Difference Between DNA and RNA. Konsyse. Available online
  • Pardi, N., Hogan, M. J., Porter, F. W., and Weissman, D. 2018. “mRNA Vaccines—A New Era in Vaccinology.” Nature Reviews Drug Discovery. 17(4): 261-279. DOI: 1038/nrd.2017.243
  • Schlacke, T., Thess, A., Fotin-Mleczek, and Kallen, K-J. 2012. “Developing mRNA-Vaccine Technologies.” RNA Biology. 9(11): 131-1330. DOI: 4161/rna.22269