[ad_1]
California [US], Jan 9 (ANI): Biochemists at the Stanford University laboratory are trying to develop a one-shot COVID-19 vaccine using nanoparticles that do not require a cold chain for storage or transport and is targeted at low levels and media. income countries.
Biochemist Peter S. Kim focused on the development of vaccines against HIV, Ebola, and pandemic influenza. But, within days of closing their campus lab space as part of COVID-19 precautions, they turned their attention to a vaccine for SARS-CoV-2.
“Our goal is to make a single injection vaccine that does not require a cold chain for storage or transport. If we get it right, it should also be cheap,” said Kim, who is the Virginia and DK Ludwig Professor of Biochemistry. The target population for the vaccine is low- and middle-income countries.
Their vaccine, detailed in an ACS Central Science article, contains nanoparticles peppered with the same proteins that make up the virus’s distinctive surface spikes. In addition to being the reason they are called coronaviruses (corona in Latin means ‘corona’), these spikes facilitate infection by fusing with a host cell and creating a passage for the viral genome to enter and take over the machinery of the virus. cell to produce more virus. Spikes can also be used as antigens, meaning that their presence in the body is what can trigger an immune response.
Nanoparticle vaccines balance the effectiveness of viral-based vaccines with the safety and ease of production of subunit vaccines. Vaccines that use viruses to deliver antigen are often more effective than vaccines that contain only isolated parts of a virus. However, they may take longer to produce, need to be refrigerated, and are more likely to cause side effects.
Nucleic acid vaccines, such as the Pfizer and Moderna mRNA vaccines that have recently been cleared for emergency use by the FDA, are even faster to produce than nanoparticle vaccines, but are expensive to manufacture and may require multiple doses . Initial tests in mice suggest that Stanford’s nanoparticle vaccine could produce immunity against COVID-19 after a single dose.
The researchers also hope that it can be stored at room temperature and are investigating whether it could be shipped and stored as a lyophilized powder. By comparison, vaccines that are more advanced in development in the United States should be stored in cold temperatures, ranging from about 8 to -70 degrees Celsius (46 to -94 degrees Fahrenheit).
The SARS-CoV-2 spike protein is quite large, which is why scientists often formulate abbreviated versions that are simpler to make and easier to use. After closely examining the beak, Kim and his team decided to remove a section near the bottom.
To round out their vaccine, they combined this shortened peak with nanoparticles of ferritin, an iron-containing protein, which has previously been tested in humans. Before the pandemic, Powell had been working with these nanoparticles to develop an Ebola vaccine.
For the mouse tests, the researchers compared their shortened beak nanoparticles to four other potentially useful variations: nanoparticles with full beaks, full beaks or partial beaks without nanoparticles, and a vaccine that contains only the section of the beak that binds to cells. during infection. Testing the effectiveness of these vaccines against the actual SARS-CoV-2 virus would have required the work to be done in a biosafety level 3 laboratory, so the researchers used a safer pseudo-coronavirus that was modified to carry spikes of SARS-CoV-2.
The researchers determined the potential effectiveness of each vaccine by monitoring the levels of neutralizing antibodies. Antibodies are proteins in the blood produced in response to antigens; Neutralizing antibodies are the specific subset of antibodies that actually act to prevent the virus from invading a host cell.
After a single dose, the two nanoparticle vaccine candidates resulted in neutralizing antibody levels at least two times higher than those seen in people who had had COVID-19, and the shortened peak nanoparticle vaccine produced a significantly neutralizing response. greater than peak binding or full peak vaccines (no nanoparticles). After a second dose, mice that had received the shortened peak nanoparticle vaccine had the highest levels of neutralizing antibodies.
Although the team’s new vaccine is specifically targeted at populations that may have a more difficult time accessing other SARS-CoV-2 vaccines, it is possible, given the rapid progress of other candidate vaccines, that it may not be necessary to address the current pandemic. . In that case, researchers are prepared to turn around again and search for a more universal coronavirus vaccine to immunize against SARS-CoV-1, MERS, SARS-CoV-2, and future coronaviruses that are not yet known.
“This coronavirus vaccine is part of the work that we are already doing, developing vaccines that are historically difficult or impossible to develop, like an HIV vaccine, and I am glad that we are in a situation where we could potentially contribute something if the the world needs it, “Kim said.
However, researchers continue to improve and refine their vaccine candidate, with the intention of bringing it closer to initial human clinical trials. (AND ME)
