According to a recent study at the La Jolla Institute for Allergy and Immunology, Zika virus and dengue fever are so closely related to one another that the body’s immune system treats Zika like another version of dengue.
The researchers said the immune response showed that pre-existing immunity to dengue virus modulates the magnitude of the body’s immune system T cell response to Zika.
While dengue fever has been known in the global community for a long time, Zika virus has been a relative unknown until the outbreak that occurred in 2015 and 2016. Most individuals infected with Zika virus show no symptoms, however, it has been linked to severe birth defects and developmental disorders in for women who are pregnant. Zika virus has also been linked to Guillain-Barré syndrome in adults.
For the study, the researchers said they examined the CD8+ T cell response to Zika virus in mice that had been either pre-exposed to dengue or had no exposure at all. The CD8+ T cells recognized the virus epitopes, otherwise known as fragments, that signal to the immune system that a cell is infected and needs to be destroyed.
The study found that mice that were previously-infected with dengue shaped the subsequent CD8+ T cell response to Zika.
“The pool of cross-reactive memory CD8+ T cells — T cells that were able to recognize both dengue and Zika epitopes — expanded at the expense of T cells that only recognized Zika epitopes,” the Institute said in a release. “In contrast, the anti-Zika CD8+ response in naïve animals was broad, including a mix of Zika-specific and dengue/Zika cross-reactive CD8+ T cells.”
In addition, the study found that immunization with Zika-specific or Zika and dengue cross-reactive peptides protected mice against infection of Zika virus.