On-demand nano-vaccines

Vaccines produced on the spot when and where a disease is breaking out might be possible thanks to engineered nanoparticles. Vaccines are usually made en masse in centralised locations, far from where they will be used. This means expensive shipping and refrigeration, and the vaccines usually have a short shelf-life. A new type of vaccine which used engineered nanoparticles has been shown to work in mice could herald the future of on-demand vaccine for humans. “We’re really excited about this technology because it makes it possible to produce a vaccine on the spot,” said François Baneyx, professor of chemical engineering at the University of Washington. “For instance, a field doctor could see the beginnings of an epidemic, make vaccine doses right away, and blanket vaccinate the entire population in the affected area to prevent the spread of an epidemic.” Typical vaccines are based on weakened pathogens or proteins found on the surface of microbes and viruses. They’re injected into the body to help prepare the immune system to fight a particular disease. The new vaccine consists of nanoparticles developed using an engineered protein that mimics the effect of an infection and binds to calcium phosphate. Baneyx’s team injected mice with the vaccine, and eight months later, mice that contracted the disease made threefold the number of protective killer T-cells compared with mice that received the disease protein and no calcium phosphate nanoparticles. The nanoparticles appear to work by ferrying the protein to the lymph node where they have a higher chance of meeting dentritic cells, a type of immune cell which plays a key role in activating a strong immune response. However, Baneyx cautions that this approach has only been proven in mice, and the development of vaccines using this method hasn’t started for humans. In the field, it is expected that genetically engineered proteins based on those displayed on the surface of pathogens would be freeze-dried or dehydrated and mixed with water, calcium and phosphate to make the nanoparticles. The approach could be useful for vaccinating people in developing countries where lead time and resources are scarce. The research was funded by the Bill & Melinda Gates Foundation and published in Nanomedicine. Just-in-time vaccines; Biomineralised calcium phosphate core-immunogen shell nanoparticles induced long-last CD8⁺ T cell responses in mice