Antibodies to dengue may alter course of Zika virus infection

Scientists at Emory Vaccine Center, in collaboration with investigators from Thailand, have found that people infected with dengue virus develop antibodies that cross-react with Zika virus.

Some of these antibodies have the potential to neutralize Zika virus – possibly providing immune protection. At the same time, in laboratory experiments, antibodies against dengue could enhance Zika virus infection of human cells.

The results are scheduled for publication in PNAS.

Zika virus is similar genetically to dengue virus and part of the same flavivirus family. They are both transmitted by Aedes mosquitos. Dengue is endemic in several countries currently experiencing Zika outbreak, leading to proposals that pre-existing dengue immunity is influencing the severity of the Zika epidemic.

“There are really two sides of the coin here: both cross-neutralization and antibody-dependent enhancement,” says Jens Wrammert, PhD, assistant professor of pediatrics (infectious diseases) at Emory University School of Medicine and Emory Vaccine Center. “We find antibody-mediated enhancement of infection with cells in the laboratory, but we have yet to clarify what effects these antibodies have on the outcome of infection in humans.” Dr. Wrammert is a faculty member in the IMP and MMG programs.

The co-first authors of the paper are Emory graduate students Lalita Priyamvada and Kendra Quicke, both MMG students. They tested serum samples from the Thai patients and also isolated antibody genes from plasmablasts, the immune cells responsible for pumping out antibodies. Co-authors also include Mehul Suthar, PhD, assistant professor of pediatrics (infectious disease) at Emory University School of Medicine and Emory Vaccine Center, and Rafi Ahmed, PhD, director of the Emory Vaccine Center and a Georgia Research Alliance Eminent Scholar. Drs. Suthar and Ahmed are also IMP and MMG faculty members.

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