FEB 13, 2019 4:23 PM PST

Dengue Meet Immune System

WRITTEN BY: Nicholas Breehl

Researchers at Duke-NUS Medical School have demonstrated for the first time a physical interaction between two types of immune cells that plays an essential role in the early fight against dengue virus infection.

Dengue virus is widespread in the tropics and is transmitted by mosquitos. Dengue virus infection incidence has grown dramatically in recent years, with estimates suggesting 390 million infections annually. It manifests as a severe, flu-like illness with high fever, and can in some cases develop into a life-threatening condition. No treatments exist for dengue fever. A vaccination does exist but is only recommended for use in people who have had dengue at least once before.

"We need much better vaccinations for dengue and for related viral pathogens that are injected into the skin by mosquitoes," said Dr. Ashley St. John, Assistant Professor of Duke-NUS' Emerging Infectious Diseases (EID) Signature Research Program and corresponding author of the study.

Very little is known about how the immune system first recognizes viruses, such as dengue virus, in the skin, she explains. Understanding how this happens could help design better vaccines for this and similar illnesses.

Dr. St. John and study co-author Dr. Chinmay Mantri, a Research Fellow in the EID Program, investigated the role played by a type of immune cell, called a mast cell, which patrols the skin to guard against infections. Mast cells are primarily known for recruiting other types of immune cells through the release of special attracting chemicals. Much is understood about how mast cells react in the presence of bacteria and parasites, but investigations into their roles with viruses have only recently begun.

The researchers analyzed how the dengue virus reacted in an animal model without any mast cells and compared the responses to animals with average numbers of mast cells to determine which reactions were dependent on the presence of mast cells.

They found that mast cells attracted several types of immune cells to the site of infection. One of these is called gamma delta T cells. Not only were delta gamma T cells attracted to the infection site, they also physically interacted with the mast cells, something not previously observed in viral infections. The delta gamma T cells bound to a receptor present on the mast cells called the endothelial protein C receptor. This so-called 'immune synapse' led to the T cells activating, proliferating, and producing interferon gamma, which initiated their role in killing cells infected with dengue.

"These [immune synapse] structures of cells in the process of communication were fascinating and visually striking to us when we first made this observation and provide a glimpse into the ways that cells must work together to fight infection," said Dr. St. John.

Professor Patrick Casey, Senior Vice Dean of Research, Duke-NUS Medical School, commented, "According to recent news, the number of dengue cases in Singapore since the start of 2019 have been at their highest in over two years. This timely study is all the more important as an example of how we develop insights from outstanding basic research that can one day lead to clinical innovations to protect against such diseases."

The study authors next plan to use the results of their research to work toward the development of better vaccines for viruses, like dengue that is spread by mosquitoes.

Sources: Science Daily, JCI, YouTube

About the Author
You May Also Like
DEC 20, 2020
Microbiology
How Do mRNA Vaccines Work?
DEC 20, 2020
How Do mRNA Vaccines Work?
Scientist Katalin Karikó studied mRNA vaccines for years. She spent years getting grant rejections, but has now helped c ...
DEC 27, 2020
Microbiology
A Potential Treatment Approach for Crohn's Disease
DEC 27, 2020
A Potential Treatment Approach for Crohn's Disease
Researchers may have found a way to treat or prevent Crohn's disease, one of the most common forms of inflammatory bowel ...
JAN 06, 2021
Immunology
What's Causing Prostate Cancer Patients to Doze Off?
JAN 06, 2021
What's Causing Prostate Cancer Patients to Doze Off?
For prostate cancer patients, androgen deprivation therapy or ADT is a standard treatment aimed at stalling the growth o ...
JAN 28, 2021
Neuroscience
Immune Cells Destroy Synapses in Multiple Sclerosis
JAN 28, 2021
Immune Cells Destroy Synapses in Multiple Sclerosis
Researchers from Germany have found that Multiple sclerosis (MS)-associated inflammation in the cerebral cortex destroys ...
MAR 25, 2021
Immunology
The Immune System Impairs Antibiotic Effectiveness
MAR 25, 2021
The Immune System Impairs Antibiotic Effectiveness
Nitric oxide, a molecule produced by the immune system, can negatively impact antibiotics’ effectiveness, says a s ...
APR 15, 2021
Immunology
COVID Vaccines Protect Breastfeeding Babies Too
APR 15, 2021
COVID Vaccines Protect Breastfeeding Babies Too
Good news for families of newborns: A new study shows that breastfeeding mothers who receive a COVID vaccine share prote ...
Loading Comments...