Researchers at the University of North Carolina took another step toward creating a vaccine to protect people from all four types of dengue virus. Dengue infects 390 million people each year, especially those in tropical and subtropical regions. In Texas, Dengue Fever led to the death of a 63-year-old woman and caused an outbreak of illness that puzzled doctors. According to Ralph Baric, PhD, one of the lead researchers, “It’s just a matter of time before dengue virus reemerges in the South, making vaccines and therapeutics a critical long-term public health priority.”
Dengue fever is a zoonotic disease transmitted by mosquitoes, and dengue virus has four types. It would be dangerous to produce a vaccine against only one form of the virus due to a phenomenon called antibody dependent enhancement, where infection with and mounted defense against one type of virus cause an enhancement of infection with a second type of the virus.
Read more about Dengue Fever.
Funded by the NIH, Dr. Baric and his colleagues Aravinda de Silva, PhD, and William Messer, PhD, discovered a commonality among the virus types that may lead to the development of a vaccine that protects against all four. A 25-amino-acid hinge domain exists on the dengue virus and acts as an epitope to human antibody binding. Each virus type has its own 25-amino-acid-long sequence, and if the sequence of dengue 3 is replaced by the sequence of dengue 4, dengue 3 is transformed into dengue 4. If the genetically mutated virus is exposed to dengue 3 antibodies, it is not affected; if it is exposed to dengue 4 antibodies, it is neutralized.