Chikungunya infections are caused by a virus of the same name and is spread by mosquitoes belonging to the Aedes genus. When infected with Chikungunya, patients develop symptoms that resemble Zika virus infections, such as fevers, acute and chronic severe joint pain and, in the worst-case scenario, an encephalitis that may be fatal. Due to climate change, mosquitoes belonging to the Aedes genus are moving North and bringing the threat of illnesses such as Chikungunya with them. There are no commercial vaccines available to prevent Chikungunya virus infection, yet as the threat of Chikungunya increases, the development of an effective vaccine is becoming urgent.
In response to this urgent need, a group of researchers at UQAM developed a new and promising vaccine strategy that uses nanotechnology. This technology involves the study of objects that are less than 100 nanometers, including molecules. The researchers at UQAM used this technology to develop a non-toxic macromolecule that is built from individual molecules. These molecules called amyloids self-assemble to form a long filament that we call a macromolecule or nanoparticle. This nanoparticle was designed so that it can display different antigens on its surface. Antigens are molecules that stimulate the immune system so that immune cells can recognise and eliminate specific pathogens. The research groups of Steve Bourgault and Denis Archambault, made up of chemists and veterinarians/immuno-virologists, respectively, collaborated to design and create a synthetic attachment point for Chikungunya virus antigens on the surface of their nanoparticle. Their careful design allows for multiple copies of Chikungunya virus antigens to be displayed on the surface of their self-assembled nanoparticle. These groups then tested whether their nanoparticle decorated with Chikungunya virus antigens would stimulate and immune response in mice. They successfully passed the first hurdle and were able to demonstrate that their nanoparticle decorated with antigens is able to stimulate a strong immune response. These finding are particularly encouraging, as their nanoparticle doesn’t need help from additional non-specific immune system stimulating compounds called adjuvants, which can be associated with adverse reactions. The next step for this group will be to test if the nanoparticle-induced immune response is strong enough to protect mice from a Chikungunya infection.
These researchers hope that this new vaccine nanotechnology can be used against other pathogens, such as avian or porcine viruses. The UQAM-based research groups of Drs Archambault and Bourgault are already working on developing a universal nanoparticle vaccine against the avian flu virus, which includes strains that infect humans and can be lethal.
Reference: Engineering and evaluation of amyloid assemblies as a nanovaccine against the Chikungunya virus. Babych M, Bertheau-Mailhot G , Zottig X , Dion J , Gauthier L , Archambault D , Bourgault S . Nanoscale. 2018 Nov 7;10(41):19547-19556.