A research group at the Massachusetts Institute of Technology (MIT) in the US said an mRNA-based vaccine against African swine fever (ASF) could be more effective — and potentially cheaper — than the conventional vaccines entering the market.
The group has identified targets on the virus that could be used to create an mRNA vaccine, a technology that uses genetic components of the targeted virus, rather than the whole virus itself, to trigger immune defenses.
Attenuated vaccines that use weakened viruses are entering the market, but questions about their safety remain.
Since an mRNA vaccine does not contain the virus itself, there is no risk of it reverting to a disease-causing form. An mRNA vaccine could prove stronger and cheaper to produce as well, according to Jianzhu Chen, an MIT Biology Professor, and Fangfeng Yuan, a Postdoctoral Researcher working on ASF vaccine design at MIT.
Prof Chen explained that an mRNA vaccine can be designed to trigger T-cells that destroy infected cells or clear them of the virus. This prevents the infected cells from producing more virus.
Conventional vaccines typically trigger the production of antibodies, proteins made by the immune system that bind to the virus and make it easier for the immune system to identify and destroy it.
“For ASF, we do not know whether neutralizing antibodies are enough, which is why it is important to get neutralizing antibodies and T-cells to kill the infected cells,” Prof Chen said.
By starting with a desired immune response in mind, Dr Yuan said the group has been able to create a vaccine that appears to trigger a stronger response against the disease — at least in preliminary mice models and healthy pigs.
Once the basic technology is in place, producing an mRNA vaccine is cheaper than producing a conventional vaccine. It is also cheaper and easier to update the vaccine for new strains of the virus, Prof Chen said.
Before that can happen, researchers must test the mRNA vaccine in pigs infected with ASF. This is a particularly expensive test, because only a handful of high-security laboratories are permitted to work with the virus. MIT is trying to raise funds to conduct these trials, Prof Chen said.
The MIT group, which typically focuses on human diseases and cancer, was first approached about ASF three years ago, and Prof Chen said the group can confirm that designing a vaccine against the virus is abnormally challenging.
“It’s a difficult scientific problem for vaccine development because it is a huge virus and because the virus can use multiple strategies to infect host pig cells. It’s not just one mechanism, so it is hard to neutralize it,” Prof Chen said.