Scientists at the University of California, USA, have demonstrated a new strategy for an RNA-based vaccine that is effective against any strain of virus and is safe even for infants and those with weak immune systems.
The vaccine, how it works, and its effectiveness in mice are described in an article published today in the scientific journal Proceedings of the National Academy of SciencesRefers to a statement from the University of California – Riverside (UCR).
“What I want to highlight regarding this vaccine strategy is that it is broad (…) applicable to any number of viruses, (…) effective against any type of virus and safe for a wide range of people,” said Rong Hai, a virologist at UCR and the author of the article, in the statement: “This may be the global vaccine we have been looking for.”
Every year, researchers try to predict which four strains of influenza virus are most likely to prevail in the upcoming flu season, and an updated vaccine should be taken annually.
The same thing happened with vaccines against SARS-CoV-2, the coronavirus that causes COVID-19, which have been reformulated to target subvariants of the dominant strains in circulation.
By targeting a portion of the viral genome common to all virus strains, the new strategy will eliminate the need to create different vaccines.
“Traditionally, vaccines contain a live, killed, or modified version of the virus. The body’s immune system recognizes the protein in the virus and launches an immune response, producing “T cells that attack the virus and prevent it from spreading” and “memory” B cells that train the immune system To prevent future attacks.
The vaccine now unveiled “uses a live, modified version of the virus”, but “does not rely” on the immune response mentioned above – which is why it can be taken by children with primary immune systems or by immunocompromised people – Rather, it is based on small RNA molecules that silence the genes that cause the disease.
“The host — a person, a mouse, whatever is infected — will produce small interfering RNAs as an immune response to the viral infection. The RNAi then kills the virus,” explained Shuwei Ding, a professor of microbiology at UCLA and lead author of the article, which is cited in the statement.
Because viruses cause disease because they produce proteins that suppress the host's RNAi response, creating a mutant virus that cannot produce the protein to suppress RNAi weakens the virus.
“It can replicate to a certain extent, but then it loses the battle to the host’s RNAi response,” Xu Ding said, adding: “The virus weakened in this way can be used as a vaccine to strengthen our immune system.”
The new strategy was tested in mutant mice, which lack T and B cells, and showed that with a single injection of the vaccine, the mice were protected from a lethal dose of the unmodified virus for at least 90 days (some studies show that nine days in rats is equivalent to one human year). almost). Even newborn mice produce small RNAi molecules, so the vaccine protects them as well.
UC Riverside has already received a US patent for its RNAi vaccine technology and the next step for researchers is to create an influenza vaccine to protect children.
“If we succeed, they will no longer depend on their mothers' antibodies,” Xu Ding said.
Scientists say the chance of a mutation in the virus avoiding this vaccination strategy is still small.
“Viruses can mutate in areas that traditional vaccines do not target. However, in this case, the target of thousands of small RNAs is your entire genome. They cannot escape,” Rong Hai said.
Through a “cut and paste” strategy, researchers also believe they can make a single vaccine for any type of virus.
“There are many well-known human pathogens, such as dengue and SARS. They all have similar viral functions, so the new strategy “should be suitable for these viruses,” Xu Ding said.
Source: Lusa
