Zika virus weakens immune response via dendritic cells

Zika virus and dengue virus are both carried by mosquitoes and can infect human immune cells known as dendritic cells. A recent study by researchers from the La Jolla Institute for Immunology and UC San Diego reveals that these two viruses attack our immune defenses in very different ways. Zika virus operates in "stealth mode." It enters dendritic cells and prevents them from alerting nearby T cells about an infection. This means the immune system can’t effectively respond to the virus. In contrast, dengue virus causes dendritic cells to release substances that trigger an aggressive immune response, leading to widespread inflammation and making it easier for the virus to spread. Understanding these differences is crucial for developing effective vaccines. Researchers aim to create vaccines that can train T cells to fight against Zika, dengue, and other related viruses. Professor Sujan Shresta highlighted that deciphering these viruses' tactics could aid in designing better vaccination strategies. The study also discovered that Zika virus suppresses a key molecule in dendritic cells, which hampers their ability to activate T cells. This is why people often have stronger immune responses to dengue than Zika. The findings may also help explain how Zika can pass through protective barriers in pregnant women and infect fetuses. Currently, there are no effective vaccines or treatments for either virus, and their spread is increasing. The World Health Organization recently reported a record number of dengue infections, with hundreds of millions affected last year. As mosquito populations expand, the risk from these viruses grows. Shresta and her team are working on a broad vaccine that could protect against multiple flaviviruses. Meanwhile, Carlin is focused on creating antiviral treatments that might stop Zika from disrupting immune responses. Scientists believe that better understanding both viruses will help develop effective preventive measures and treatments.