Sneha Singhal, Jaypee Institute of information technology, Noida
COVID-19 vaccine candidates developed by researchers at UC San Diego can withstand the heat. What are their key ingredients? Plant or bacterial viruses.
Vaccine technology:
We are still in the early phases of developing the new refrigerator-free COVID-19 vaccine. Vaccine candidates stimulated the mice to produce high levels of antibodies that neutralize COVID-19, a virus that causes SARS-CoV-2. In addition to helping global distribution efforts, the vaccines could make a big impact in rural areas or resource-poor communities if they are proven to be safe and effective. Vaccine technology developed by Nicole Steinmetz is thermally stable, so building ultra-low temperatures freezers or bringing specialized trucks to remote areas is not feasible.
Researchers have developed two possible COVID-19 vaccines. One involves the use of plant viruses, like the cowpea mosaic virus. In the other, a bacteriophage, called Q beta, is used. The two vaccines used similar recipes. Researchers made nanoparticles of plant and bacteriophage viruses using cowpea plants and Ecoli bacteria. To attach the spike protein to these nanoparticles, researchers first harvested the sample and then harvested nanoparticles. Animals and humans are not infected with the finished products because they look like infectious viruses.
Viruses evade the immune system because the spike protein on their surface activates the immune system. Their vaccines utilize plant virus and bacteriophage technologies. Large-scale production of them can be easy and inexpensive. Steinmetz said this type of growing is fairly easy and doesn’t require complex infrastructure. The biopharmaceutical industry has already established fermentation by using bacteria. Moreover, nanoparticles of plant viruses and bacteriophages are extremely stable at high temperatures. Therefore, vaccines do not need to be kept cold during storage and shipment. Heat can also be used to fabricate them.
As a result, the team has started packaging their vaccines into microneedle patches and polymer implants. The vaccine candidates are mixed with polymers and melted in an oven close to 100°C. By combining the plant virus and bacteriophage nanoparticles directly with the polymers, vaccine implants and patches can be made rapidly and easily.
COVID-19 vaccines should be more accessible to the public, and people should have a variety of options for getting them. A single injection of these implants, which slowly release the vaccine over a month, would be required. People would also be able to self-administer vaccinations via microneedle patches fitted on the arm without feeling pain or discomfort.
Vaccine against the pan-coronavirus:
Scientists found that the same antibodies neutralized the SARS virus as well. This all falls to the piece of the coronavirus spike protein that is attached to the nanoparticle’s surface. SARS-CoV-2 and SARS virus share an epitope, one of Steinmetz’s pieces of evidence. A postdoctoral researcher in Steinmetz’s lab said that finding an epitope so well conserved among other deadly coronaviruses enables such profound neutralization. This raises hopes for how a future pandemic vaccine might be developed. The SARS-CoV-2 epitope also has the advantage of being unaffected by any mutations yet reported for this virus. It has no direct binding affinity to cells since it derives from a region of the spike protein. Contrary to the COVID-19 vaccines that are currently administered, this epitope comes from the protein’s binding region. Many mutations have occurred in this region. A number of these mutations have increased the contagiousness of the virus. Consequently, the new COVID-19 vaccines may have a potential impact on the variants of concern, according to Ortega-Rivera.
The plug-and-play vaccine:
This vaccine technology also excites Steinmetz because of the flexibility it offers to create new vaccines. The technology may not be able to stop COVID-19, but it can be adapted to combat the next threat, the next virus X,” Steinmetz said. Her vaccines are “plug and play,” she says. Plant viruses or bacteriophages are grown from plants or bacteria, respectively, and then the target virus, pathogen, or biomarker is attached to the surface. The only thing that differs is the antigen that we stick to the surface. For all the components to work together, Steinmetz used the same polymers, equipment, and chemistry. Vaccines made this way do not need to be kept cold. It is possible to package them into implants or microneedles patches. Alternatively, they can be administered directly through shots. The Steinmetz and Pokorski labs have developed candidates for vaccines against diseases like HPV and cholesterol using this recipe in previous studies. Now they have proven that it can also produce COVID-19 vaccine candidates.
The next steps:
A long way still needs to be travelled before vaccines are ready for clinical trials. Further testing will be conducted in vivo to determine whether the vaccine protects against COVID-19 as well as its variants and other deadly coronaviruses.
Also read: Insulin resistance: A new approach to tackle the condition
References: Diego, U. of C.-S. (n.d.). These fridge-free COVID-19 vaccines are grown in plants and bacteria. Retrieved September 15, 2021, from https://phys.org/news/2021-09-fridge-free-covid-vaccines-grown-bacteria.html
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