Mosquito virus could lead to new vaccines and drugs

September 21, 2012

A mosquito sample collected three decades ago in Israel's Negev Desert has yielded an unexpected discovery: a previously unknown virus that's closely related to some of the world's most dangerous mosquito-borne pathogens but, curiously, incapable of infecting non-insect hosts.

Researchers believe this attribute could make the Eilat a uniquely useful tool for studying other alphaviruses, a genus of largely mosquito-borne pathogens that includes the viruses responsible for chikungunya, Venezuelan , western equine encephalitis and eastern equine encephalitis. In addition, the researchers say, Eilat could also aid in the development of new alphavirus vaccines, therapies and diagnostic techniques.

"This virus is unique—it's related to all of these mosquito-borne viruses that cause disease and cycle between mosquitoes and animals, and yet it is incapable of infecting vertebrate cells," said University of Texas Medical Branch at Galveston graduate student Farooq Nasar, lead author of a paper on the virus now online in the . "It's a gift, really, because we can compare it to other alphaviruses and figure out the basis of their ability to infect a variety of animals, including humans."

Eilat was discovered in a virus sample that Joseph Peleg of Hebrew University sent to UTMB's Dr. Robert Tesh, an author of the PNAS paper and director of the World Reference Center for Emerging Viruses and Arboviruses. The collection holds over 5,000 identified viruses and dozens of unidentified samples like the one contributed by Peleg.

All the researchers knew about Peleg's specimen was that it killed insect cells while leaving untouched, a very unusual behavior. So they sent it to a lab at Columbia University that specializes in doing highly intensive searches for the genetic material of viruses, a process called "deep sequencing." As it turned out, there were two new viruses in the sample. One virus killed insect cells, and the other—Eilat virus—infected them without doing any harm.

"We were extraordinarily lucky to have that other virus in our sample, because without the cell death it caused, we never would have done the work that led us to Eilat," Nasar said. "Essentially, we found it by accident."

Eilat's inability to grow in animal cells—even its genetic material cannot replicate in them—makes it unique among alphaviruses, and it also makes it likely that the virus could be uniquely valuable to researchers who study alphaviruses and work to protect humans and domestic animals from them. For example, the UTMB researchers say, Eilat could be transformed into a vaccine against one of its dangerous relatives by making changes to the genes that produce its envelope proteins, which are exposed on virus particle surfaces and stimulate the critical parts of the immune response.

"We have taken the genes for the envelope proteins of very dangerous viruses like eastern equine encephalitis and used them to replace the genes for Eilat's structural proteins," Nasar said. "That gives us viruses that we can grow in that can't do anything in vertebrate cells at all, but still produce immunity against eastern equine encephalitis —they can be used to vaccinate animals, and hopefully someday people."

A variety of Eilat-based "chimeric viruses"—viruses made by combining from other viruses—could be used to study the interactions between host cells and dangerous alphaviruses, leading to the development of antiviral drugs. The viruses could also serve as the basis for new diagnostic tools that could be deployed in an alphavirus outbreak. Because these chimeras, like Eilat, would not be able to infect vertebrates, such research could be done without the elaborate and often cumbersome containment precautions needed for working with pathogens like chikungunya, Venezuelan equine encephalitis, or eastern and western equine encephalitis.

Related Stories

Recommended for you

'Human chronobiome' study informs timing of drug delivery, precision medicine approaches

December 13, 2017
Symptoms and efficacy of medications—and indeed, many aspects of the human body itself—vary by time of day. Physicians tell patients to take their statins at bedtime because the related liver enzymes are more active during ...

Study confirms link between the number of older brothers and increased odds of being homosexual

December 12, 2017
Groundbreaking research led by a team from Brock University has further confirmed that sexual orientation for men is likely determined in the womb.

Potassium is critical to circadian rhythms in human red blood cells

December 12, 2017
An innovative new study from the University of Surrey and Cambridge's MRC Laboratory of Molecular Biology, published in the prestigious journal Nature Communications, has uncovered the secrets of the circadian rhythms in ...

Estrogen discovery could shed new light on fertility problems

December 12, 2017
Estrogen produced in the brain is necessary for ovulation in monkeys, according to researchers at the University of Wisconsin-Madison who have upended the traditional understanding of the hormonal cascade that leads to release ...

Time of day affects severity of autoimmune disease

December 12, 2017
Insights into how the body clock and time of day influence immune responses are revealed today in a study published in leading international journal Nature Communications. Understanding the effect of the interplay between ...

3-D printed microfibers could provide structure for artificially grown body parts

December 12, 2017
Much as a frame provides structural support for a house and the chassis provides strength and shape for a car, a team of Penn State engineers believe they have a way to create the structural framework for growing living tissue ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.