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The American RNA vaccine against coronavirus was tested on mice and monkeys
The American "self-propagating" vaccine has successfully protected the body of mice and monkeys from infection with a new type of coronavirus. The preliminary test results of the drug developers have been published in the electronic scientific library bioRxiv (Erasmus et al., Single-dose replicating RNA vaccine induces neutralizing antibodies against SARS-CoV-2 in nonhuman primates).
"Our experiments showed that a single injection of the vaccine forced the body of rodents and monkeys to produce antibodies that can neutralize a new type of coronavirus (SARS-CoV-2), in about the same quantities as the body of people who have had COVID-19. All this indicates the prospects for further development of RNA vaccines of this type," the researchers write.
In recent months, scientists from many countries have begun testing various vaccines against a new type of coronavirus. Some of them are tested in animal experiments, and others are tested on volunteers. The first results of the tests, as scientists expect, will be known only in about a year and a half, if the method of testing vaccines does not change. For example, trials of Russian vaccines are promised to begin in June.
Many drugs are based on untested technology, according to which RNA fragments must be injected into human cells, forcing them to produce a large number of virus proteins. Scientists are developing both classic inactivated and recombinant vaccines based on weakened viral particles and finished fragments of the virus envelope. In both cases, it will be very difficult to establish mass production of these drugs, and there are no guarantees of success yet.
First successes
One of these experimental drugs is a vaccine that was developed by scientists under the guidance of Professor Deborah Fuller of Washington State University (USA) together with specialists from the pharmaceutical company HDT. It is a lipid nanoparticle that can penetrate into human cells and deliver fragments of the virus RNA inside them.
The main difference between this vaccine and other drugs of this kind is that it is based on self-replicating viral RNA (replicon RNA, repRNA), which can copy itself, but not form new viral particles. Such an approach, scientists hoped, would force the patient's body to produce more viral proteins. As a result, a strong immune response is more likely to appear.
Formation of a vaccine complex after mixing lipid LION nanoparticles (Lipid organic Nanoparticles) with self-replicating viral RNA.
To test whether this is actually the case, Fuller and her colleagues tested the vaccine on transgenic mice and pig-tailed macaques. Experiments have confirmed that thanks to single injections of small doses of the vaccine, the body of primates and rodents really began to produce large amounts of antibodies that can combine with different parts of the SARS-CoV-2 envelope and neutralize the virus. Subsequent experiments showed that the vaccine worked equally well on both young and elderly animals, protecting them from coronavirus attacks.
Such results, as the researchers note, opened the way for clinical trials of the vaccine, which was given the name HDT-301. Scientists hope that experiments on volunteers will quickly help them prove that the vaccine is safe for humans and acts on them as effectively as on primates and rodents.
It should be added that the scientists' article was not reviewed by independent experts and editors of scientific journals, as is usually the case in such cases. Therefore, conclusions from it and similar articles should be treated with caution.
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