Noroviruses are pernicious intestinal viruses. They cause violent vomiting and diarrhea, and people ill with the virus remain contagious up to three days after they seem to recover.
Although a vaccine for these viruses is in clinical trials, there is still no medication to combat them. That’s in part because researchers have not been able to culture human noroviruses so they can test potential treatments — until now, according to a study by University of Florida Health researchers published Friday, Nov. 7 in the journal Science.
UF Health researchers Stephanie Karst, Ph.D. (right), and Melissa Jones, Ph.D., have discovered how to grow the norovirus in human cells, opening the way to develop antivirals and vaccines.
UF Health researcher Stephanie Karst, Ph.D., has found a way to grow a human norovirus by identifying a cell it targets in the intestine.
“The biggest hurdle to doing norovirus research for its entire history — it was discovered in 1972 — has been that we can’t culture the human viruses in a cell culture dish,” said Karst, an associate professor in the department of molecular genetics and microbiology in the UF College of Medicine. “That complicates every aspect of research. We can’t study how it replicates, we can’t test therapeutics and we can’t generate live virus vaccines.”
According to the Centers for Disease Control and Prevention, in the United States, human noroviruses cause 19 to 21 million cases of illness per year, and contribute to 56,000 to 71,000 hospitalizations and 570 to 800 deaths, mostly in young children and older adults. Noroviruses are resistant to many common disinfectants. Very little of the virus is needed to infect a host, so a surface may still contain enough virus to infect a person even after it is cleaned.
Previously, researchers speculated that noroviruses primarily target intestinal epithelial cells, which line the intestine and protect it from pathogens, Karst said. However, this new research demonstrates that the virus targets B cells, a type of white blood cell common in the intestine.
“That’s a big surprise,” Karst said. “You would think that any virus that’s going to target the intestine would instead target the intestinal epithelial cells because that’s the first cell the virus is going to encounter.”
Researchers also were surprised to find that bacteria present in the body’s gut flora, also known as commensal bacteria, helped the human norovirus infect B cells. Karst said scientists have long known that noroviruses need a particular kind of carbohydrate to infect cells.
“What we’ve shown is that noroviruses attach to that carbohydrate expressed on commensal bacteria, and that this interaction stimulates viral infection of the B cell,” Karst said. “This is a really exciting, emerging theme. A variety of intestinal viruses seem to exploit the bacteria that are present in our intestines all the time. These viral infections are enhanced by the presence of bacteria in the gut.”
UF research scientist Melissa Jones, Ph.D., a co-author on the paper, said the idea to study B cells came from Karst’s research on mouse noroviruses. UF scientists detected virus in Peyer’s patches, pockets of lymphoid nodules that line the intestine and survey the organ for pathogens.
This system can now be used to study norovirus replication and assess effectiveness of therapeutics and disinfectants, though more work needs to be done to increase its efficiency. Karst and Jones said while this is the first time researchers have been able to culture a human norovirus, the virus does not replicate to high levels in the current system, which hinders growth of the virus in the laboratory.
“Ultimately, this system should open up new avenues for norovirus vaccine and antiviral drug development,” Karst said.
Morgan Sherburne | EurekAlert!
Scientists discover the basics of how pressure-sensing Piezo proteins work
22.08.2019 | Weill Cornell Medicine
Protein-transport discovery may help define new strategies for treating eye disease
22.08.2019 | Scripps Research Institute
Since their experimental discovery, magnetic skyrmions - tiny magnetic knots - have moved into the focus of research. Scientists from Hamburg and Kiel have now been able to show that individual magnetic skyrmions with a diameter of only a few nanometres can be stabilised in magnetic metal films even without an external magnetic field. They report on their discovery in the journal Nature Communications.
The existence of magnetic skyrmions as particle-like objects was predicted 30 years ago by theoretical physicists, but could only be proven experimentally in...
Theoretical physicists at Trinity College Dublin are among an international collaboration that has built the world's smallest engine - which, as a single calcium ion, is approximately ten billion times smaller than a car engine.
Work performed by Professor John Goold's QuSys group in Trinity's School of Physics describes the science behind this tiny motor.
Together with the University of Innsbruck, the ETH Zurich and Interactive Fully Electrical Vehicles SRL, Infineon Austria is researching specific questions on the commercial use of quantum computers. With new innovations in design and manufacturing, the partners from universities and industry want to develop affordable components for quantum computers.
Ion traps have proven to be a very successful technology for the control and manipulation of quantum particles. Today, they form the heart of the first...
Experimental progress towards engineering quantized gauge fields coupled to ultracold matter promises a versatile platform to tackle problems ranging from condensed-matter to high-energy physics
The interaction between fields and matter is a recurring theme throughout physics. Classical cases such as the trajectories of one celestial body moving in the...
Soft robots have a distinct advantage over their rigid forebears: they can adapt to complex environments, handle fragile objects and interact safely with humans. Made from silicone, rubber or other stretchable polymers, they are ideal for use in rehabilitation exoskeletons and robotic clothing. Soft bio-inspired robots could one day be deployed to explore remote or dangerous environments.
Most soft robots are actuated by rigid, noisy pumps that push fluids into the machines' moving parts. Because they are connected to these bulky pumps by tubes,...
16.08.2019 | Event News
14.08.2019 | Event News
12.08.2019 | Event News
23.08.2019 | Medical Engineering
23.08.2019 | Power and Electrical Engineering
23.08.2019 | Life Sciences