Scientists have discovered a new class of extremely potent antibodies that effectively neutralize all of the viruses that cause dengue fever, a rapidly emerging disease that has become a leading cause of illness and death in tropical and subtropical regions. The discovery raises hope that these antibodies could be used in the development of a much sought after universal vaccine and better laboratory tests for dengue viruses.
Dengue is a mosquito-borne viral infection that has rapidly emerged in the past 50 years. Around one-third of the world’s population live in areas at risk for infection, and as many as 400 million dengue infections are estimated to occur annually in over 100 countries. The disease is caused by any one of four related viruses, for which there are no licensed vaccines or specific drugs, although one vaccine is going through trials at the moment. This means that currently, the only way to prevent infection is by reducing transmission through vector control measures, such as mosquito nets or even genetically modified mosquitoes, which are being trialed in various countries.
Dengue fever is characterized by severe, flu-like symptoms that usually disappear within a week. Occasionally, however, the infection develops into a potentially lethal complication called severe dengue, which claims around 22,000 lives a year. Furthermore, infection with one of the viruses means you are more likely to develop severe disease if you are subsequently infected with a different dengue virus. A vaccine that protects against all four viruses is therefore, realistically, the only way that the disease is going to be controlled. And new work suggests that this could be within reach, thanks to the discovery of a new class of potent antibodies.
The antibodies were identified by researchers from Imperial College London and the University of Melbourne after they analyzed the blood of a group of infected patients. As described in Nature Immunology, they discovered that a significant portion of their immune response came from a class of antibodies that targeted a previously unidentified viral epitope—a unique region that components of the immune system can bind to and recognize—that’s present on all four dengue viruses. This structure was found to be a molecular bridge that joins two proteins on the virus’ surface.
The researchers tested out this class of antibodies on dengue viruses produced in both insect and human cells, and found that they were capable of successfully neutralizing all four viruses. Having successfully manufactured a batch of these antibodies, the researchers are hopeful that they can be tested out in trials soon. It’s possible that they could be used to develop a vaccine, or even as a form of therapy to help infected individuals clear the virus. Alternatively, it may be possible to synthesize the molecular bridge and use that as a vaccine, which would prime the immune system for attack should it subsequently encounter any of the dengue viruses.
[Via University of Melbourne, Nature Immunology and The Guardian]