There are many factors that affect and complicate the development of a new vaccine.
What Riccardo Baccheschi, CEO of AchilleS Vaccines, and his team are working on could make the process a lot faster in the future: the modified outer membrane vesicles (mOMVs) technology platform. mOMVs function is an ideal delivery platform for bacterial vaccines as well as against viral antigens like Covid-19, carrying the antigens and helping them to trigger the intended immune system reaction.
The vesicles can be imagined as tailor-made bubbles that originate from the bacterial surface, Baccheschi explains on a video call from AchilleS’ offices in Siena. In their growth phase, gram negative bacteria naturally release membrane vesicles which match the composition of the bacterial outer surface. That is the pathogen part which is primarily exposed to the immune system. “The OMV helps the antigens to be recognized by the immune system”, says Baccheschi. “That exposure leads to an effective response of the immune system, that is very important for a vaccination’s rapid and durable protection.” Ultimately the mOMV, depending on the related genetical engineering, can either expose natural bacterial antigen or heterologous antigens from non-bacterial pathogens.
The trick is to “instruct” the bacteria to produce the “right vesicles” in an industrially significant amount. Scientists have taken advantage of this natural process to artificially create mOMVs, by inducing bacteria to hyperproduce OMVs. “When done right, the outcome is the closest thing to nature”, says Baccheschi. “You might end up with an immunization very close to the natural process of someone who got infected by the live bacteria.”
The idea behind OMVs is not new, but since the discovery, a lot has changed. When their potential use was first discovered, the platform they provided was quite rigid and could only be used in very limited cases. In the beginning, mOMVs were chemically extracted resulting in a significant alteration of the antigenicity. With more recent technological evolutions that emerged around six years ago, mOMVs were able to be better genetically modified and purified. Today, the mOMVs technology platform might be considered one of the most promising platforms for vaccine developments, says Baccheschi, because they became a lot more flexible and sustainable. mOMVs are a potential platform for a multitude of purposes, for example for other viruses like Ebola or parasites like Malaria, but also in the prevention of antimicrobial resistance or the treatment of cancer.
Besides its resemblance to a natural immune response and its versatility, mOMVs will also be very cost- and time-efficient, says Baccheschi. Most of bacterial vaccines today, for example, require 15+ manufacturing steps, while with mOMVs this could be reduced to four or five, he explains. “This means only a third of the complexity and drastic reduction of production time and costs.”
Right now, AchilleS Vaccines is working together with Dr Rino Rappuoli in Siena on a monoclonal antibody project, mAbCo19, as a potential way to fight Covid-19. The next step could be, as Baccheschi explains, to figure out which antigens could be the best candidates to be used with the mOMV technology. Early discoveries suggest that a SARS vaccine, a virus which is quite similar to Covid-19, could be developed using mOMVs, says Baccheschi. “There are many indications that it can work with Covid as well.”