Researchers at UCSD Discover Zika Attacks Immune Cells

A UC San Diego study found the Zika virus targets and infects immune cells rendering them useless.

The study published the week of September 10 in the journal Proceedings of the National Academy of Sciences included a new method of examining the immune cells by tagging which ones were infected by the virus and which ones weren’t.

The differences in the infected and uninfected cells, called macrophages, were stark, according to Dr. Christopher Glass. Glass is a professor in the departments of Medicine and Cellular and Molecular Medicine at UC San Diego School of Medicine.

In pregnant women, the Zika virus can stunt neonatal brain development leading to babies born with abnormally small heads, a condition known as microcephaly. Adult brain cells may also be vulnerable to the virus.

“We know Zika virus destroys a number of cell types, particularly in the brain, but we don’t yet understand how it causes cells to die or malfunction,” said first author Aaron Carlin, MD, PhD, associate physician at UC San Diego School of Medicine.

Previous methods of studying Zika required cells that had been exposed but not necessarily infected by the virus, which presented the problem of examining both infected and uninfected cells, the study’s authors said.

The examination of strictly infected cells allowed researchers to discover that the virus blocks genes that should trigger an immune response and suppresses gene production in general.

“If your goal is to see what a virus is doing to a cell, you need to focus on only infected cells to get true representation,” Carlin said.

The difference they found with the new technique was startling.

“We were surprised at just how different infected and uninfected cells looked, in terms of the genes they had turned on or off, even two cells next to each other,” Glass said. “What’s amazing is that even though they are exposed to the same environment, their responses are completely different. And now we know those differences are truly due to the virus, not any of the other events going on around the cells during an immune response.”

Carlin and Glass intend on applying the cell sorting technique in the future on other viruses and other cells infected by the Zika virus.

Microcephaly, the condition caused by the Zika virus in pregnant women, can also cause seizures, developmental delays and cognitive issues like vision and hearing loss, according to the Center for Disease Control and Prevention.

Doctors are working toward discovering more about how the Zika virus works so they can one day prevent the condition from developing in newborn babies.  

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