Dengue fever is caused by dengue virus and it is one of the most common diseases transmitted by mosquitoes. Although the percentage of patients who die from dengue virus is low, the burden of disease and economic impact are high. There are currently no medicines to combat dengue fever. A vaccine is available, but it is not suitable for children and tourists. That is why a better vaccine is desperately needed.
Multiple variants of the virus
The development of a dengue fever vaccine is hampered by the fact that there are four serotypes of the dengue fever virus. During a first infection, the immune system is activated to produce antibodies. These antibodies provide lifelong protection against the same serotype, but cannot stop infection with another serotype, and even worsen the disease. A good vaccine should therefore offer protection against all four serotypes.
Empty virus particles as a vaccine
There are many different ways to make a vaccine. One of these are so-called virus-like particles (VLPs). VLPs are particles that consist of the envelope proteins of the virus. On the outside they look like a virus but they do not contain genetic material. There are already several vaccines on the market that make use the VLP-technique.
Multiple virus variants in one vaccine
In collaboration with colleagues in Germany and the USA, scientists from BPRC have now generated a dengue virus vaccine based on dengue VLPs. The unique thing about this experimental vaccine is that parts of the envelope proteins, from two different serotypes are combined, to make one type of VLPs. The article describes how the VLPs are made and purified, and how the biochemical quality was tested with, among other things, electron microscopy.
Does the experimental vaccine activate the immune system?
To determine whether the experimental vaccine is actually immunologically active, rabbits were vaccinated. After vaccination, the serum of the animals contained high concentrations of antibodies. The antibodies were further investigated using non-animal testing techniques. These tests showed that the antibodies were able to bind to the dengue virus, but that they could not sufficiently inactivate the virus.
Even better VLPs in the future
Despite the finding that the vaccine in its current form is not good enough, we show that it is possible to make a dengue VLP vaccine representing more than one serotype. The researchers are currently working on improving the technology so that they can develop new and better VLPs.
Find out more in the online publication.