2020-04-08T13: 09 + 0300
2020-04-08T14: 08 + 0300
Created an artificial virus blocking coronavirus infections
There are still no vaccines in the world that protect people from coronavirus infections, such as COVID-19 or its preceding SARS (Severe Acute Respiratory Syndrome, also known as SARS) and MERS (Middle East Respiratory Syndrome).
In a new study, scientists describe a promising approach based on the creation of a genetically engineered virus containing S-protein fragments from which thorns of coronaviruses are folded, through which they bind to receptors on the surface of cells, which allows the virus to penetrate into healthy cells.
Scientists have created, based on the natural virus parainfluenza 5 (PIV5), which is known in dogs but safe for humans, to modify the virus by adding a gene to PIV5 that causes infected cells to produce S-glycoprotein, similar to that found in coronavirus spikes.
The authors tested the resulting virus in mice, using it as a vaccine against the MERS virus. It is known that the MERS virus does not infect mice; therefore, model animals were created for the experiment in which DPP4 protein is expressed, which is used by the MERS virus as an entry point into human cells.
Laboratory tests showed that a single dose of the viral vaccine, administered through the nose, effectively induced infected cells to produce an S protein, which in turn elicited immune responses against this protein in the host animal.
Four weeks after the mice received the vaccine, they were exposed to a strain of MERS virus adapted to the mice to cause a deadly infection. The MERS virus was also transmitted to control groups of mice that received the geneless PIV5 vaccine for S protein or the intramuscular vaccine with inactivated MERS virus.
All mice immunized with the modified PIV5 virus survived after infection with the MERS virus. In contrast, all mice immunized with PIV5 without S-protein died from infection. An intramuscular vaccine against the inactivated MERS virus protected only 25 percent of mice from a deadly infection. In addition, in animals that received the intramuscular vaccine, the researchers recorded elevated levels of leukocytes-eosinophils, which indicates infection and inflammation, which, according to the authors, makes us think about the safety of intramuscular vaccines with inactivated coronavirus.
The authors have now focused on creating a modified virus that protects against SARS-CoV-2. According to McCray, “finding an effective vaccine against coronavirus that causes COVID-19 is a matter of time. For the first time, one hundred percent of the population will not be exposed to the virus, which means that we do not yet know whether people will receive long-term immunity from infection SARS-CoV-2, and it’s important to think about ways to protect people. “