Experts believe the finding will pave the way towards developing new and effective vaccines against the deadly virus. While previously identified antibodies could only kill DENV-2 of a certain morphology, the newly discovered antibody can kill DENV-2 of all morphologies.
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These 4 “serotypes” (DENV-1, DENV-2, DENV-3 and DENV-4) are a challenge to treat because the antibodies generated to fight one of the serotype does not offer protection against the others.
The researchers identified an HMAb called 2D22 that was able to bind to a variety of epitope proteins of the DENV2 serotype, and in mouse models, the antibody stopped the virus from fusing to its target cell, preventing infection. Dengue infects about 390 million people every year and has been indicted as the major cause of illness and death in the tropics.
The antibody also blocked the binding of the other class of antibodies that otherwise would enhance infection. They can cause various symptoms such as fever, vomiting, rashes, bleeding and joint pains.
“The virus injects its own genes in the cell to make more of itself”, said Vanderbilt University Medical Center’s Vaccine Center director and co-author of the study James Crowe.
In the study, research fellow Guntur Fibriansah and associate professor Shee-Mei Lok led the researchers from the Duke NUS Emerging Infectious Diseases Programme showed how DENV-2 is neutralized by a potential human antibody. Dengue is transmitted by the bite of mosquitoes, most commonly the Aedes aegypti mosquito, which can carry the four virus serotypes.
It is no longer a restrained crisis as in the past 50 years, the dengue virus has begun spreading from nine countries to over one hundred nations, increasing its rate of infection by 30 all through the world.
They froze samples at very low temperatures so they could visualise antibody-antigen binding nearly down to the atomic level.
Dr. Crowe and colleagues note that such antibodies can also “cross-react”, leading to infection with a second serotype and raising the risk of DHF.
There is no licensed vaccine or drugs to fight the dengue virus at present.
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With this determination of the structure of the monoclonal antibody, health researchers are positive they can develop the first effective therapy as well as vaccine against dengue. “So, if we actually move forward in developing a therapeutic for humans, it probably would be a mixture or cocktail of four antibodies, and this would be one of the antibodies that corresponds to one of the four viruses”. In a paper published today in the online edition of prestigious scientific journal Science, Prof Lok and other researchers showed how another antibody could neutralise serotype 2.
