Dengue fever is a mosquito-borne tropical disease that causes fevers, rash, headaches, joint pain, and sometimes death. The virus that causes dengue fever comes in four types, all of which can cause the full spectrum of disease. No vaccine or targeted treatment is available for the infection.
When a person is infected with one type of dengue virus, his or her immune system usually develops a lifelong resistance, or immunity, to that specific virus type, but only short-term immunity to the other types. Subsequent infection with a different type increases the risk of severe complications.
Different people’s immune systems develop resistance to the different types of dengue virus in different ways. Some people produce antibodies that effectively neutralize the virus. Scientists do not yet understand how these special immune responses occur on a molecular level in humans. This knowledge might help researchers develop a vaccine against the virus.
One group of researchers, including some in the Section on Membrane Biology within the Division of Intramural Research Program in Physical Biology, recently studied an antibody produced by chimpanzees that neutralizes dengue virus type IV. Using molecules in test tubes and computer models, the researchers examined in detail how the chimp antibody interacts with part of a molecule on the virus’ surface. This viral molecule acts as a key, opening up host cells to let the virus invade. The research points to the means through which the antibody interferes with the virus’ “unlocking” process.
Then, looking at blood samples from people recovering from dengue virus type IV infections, the researchers found that some of these people produced antibodies that seemed similar to the chimp antibodies used in the laboratory studies. This insight brings researchers closer to developing a way to neutralize the dengue virus in humans (PMID: 22139356).