Context: An experimental mRNA-based vaccine from Moderna Inc and Merck & Co reduced the risk of melanoma spread by 65% when compared with immunotherapy alone in a mid-stage trial the results, presented at the American Society of Clinical Oncology meeting in Chicago.
About m-RNA
- Messenger RNA (mRNA) is a type of single-stranded RNA involved in protein synthesis.
- It is made from a DNA template during the process of transcription.
- The role of mRNA is gene expression and to carry protein information from the DNA in a cell’s nucleus to the cell’s cytoplasm (watery interior).
- It carries the genetic information from DNA (deoxyribonucleic acid) to the ribosomes, where proteins are synthesized.
- DNA is transcribed into mRNA, which is then translated into proteins. mRNA acts as an intermediary between DNA and proteins, carrying the genetic instructions encoded in the DNA to the protein-making machinery of the cell.
m-RNA Vaccine
- Vaccines help prevent infection by preparing the body to fight foreign invaders (such as bacteria, viruses, or other pathogens).
- m-RNA vaccine delivers molecules of antigen-encoding mRNA into immune cells, which use designed mRNA as a blueprint to build foreign protein that would normally be produced by a pathogen (such as a virus) or by a cancer cell.
- These protein molecules stimulate an adaptive immune response that teaches the body to identify and destroy the corresponding pathogen or cancer cells.
How does it work?
- An mRNA vaccine uses a copy of mRNA to produce an immune response.
- The vaccines target neoantigens, new mutations only present on tumors.
- Aiming at these proteins allows the immune system to kill cancer cells while leaving healthy tissue unscathed. The trick is determining which of many mutations is driving the cancer.
- To accomplish this, tumors are removed and their genetic makeup is mapped using DNA sequencing.
- Companies use artificial intelligence to predict which mutations will be effective targets. These are used to build an individualised vaccine targeting only mutations in the patient's tumor.
Benefits
- mRNA vaccines are not constructed from an active pathogen (or even an inactivated pathogen), they are non-infectious. In contrast, traditional vaccines require the production of pathogens, which, if done at high volumes, could increase the risks of localized outbreaks of the virus at the production facility.
- mRNA vaccines could trigger the innate immune system (the immunity we’re born with), providing an extra layer of defence.
- mRNA vaccines can be developed and manufactured quickly compared to traditional vaccines. Once the genetic sequence of a target antigen is known, the production of mRNA can be initiated promptly.
- mRNA vaccines are highly versatile. They can be designed to target various pathogens by simply changing the mRNA sequence to encode the desired antigen.
Challenges
- Storage: Because mRNA is fragile, some vaccines must be kept at very low temperatures to avoid degrading and thus giving little effective immunity to the recipient.
- Adverse reaction: Excessive immunological responses and associated signs and symptoms, including fever and sore arm at the injection site are associated with mRNA vaccine.
- Manufacturing Scalability: The manufacturing processes, including the production and purification of mRNA molecules, require sophisticated technology and expertise.
Transcription
- The process by which a cell makes an RNA copy of a piece of DNA. This RNA copy, called messenger RNA (mRNA), carries the genetic information needed to make proteins in a cell.
Gene expression
- The process by which the information encoded in a gene is used to synthesize a functional gene product, such as a protein or a non-coding RNA molecule.