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!
Mutations in donors' stem cells may cause problems for cancer patients
17.01.2020 | Washington University School of Medicine
Overactive brain waves trigger essential tremor
17.01.2020 | Columbia University Irving Medical Center
Styrofoam or copper - both materials have very different properties with regard to their ability to conduct heat. Scientists at the Max Planck Institute for Polymer Research (MPI-P) in Mainz and the University of Bayreuth have now jointly developed and characterized a novel, extremely thin and transparent material that has different thermal conduction properties depending on the direction. While it can conduct heat extremely well in one direction, it shows good thermal insulation in the other direction.
Thermal insulation and thermal conduction play a crucial role in our everyday lives - from computer processors, where it is important to dissipate heat as...
In order to advance the transfer of research developments from the field of quantum sensor technology into industrial applications, an application laboratory is being established at Fraunhofer IAF. This will enable interested companies and especially regional SMEs and start-ups to evaluate the innovation potential of quantum sensors for their specific requirements. Both the state of Baden-Württemberg and the Fraunhofer-Gesellschaft are supporting the four-year project with one million euros each.
The application laboratory is being set up as part of the Fraunhofer lighthouse project »QMag«, short for quantum magnetometry. In this project, researchers...
Microtubules, filamentous structures within the cell, are required for many important processes, including cell division and intracellular transport. A...
Researchers from the University Hospital Zurich, ETH Zurich, Wyss Zurich and the University of Zurich have developed a machine that repairs injured human livers and keep them alive outside the body for one week. This breakthrough may increase the number of available organs for transplantation saving many lives of patients with severe liver diseases or cancer.
Until now, livers could be stored safely outside the body for only a few hours. With the novel perfusion technology, livers - and even injured livers - can now...
A balloon-borne scientific instrument designed to study the origin of cosmic rays is taking its second turn high above the continent of Antarctica three and a half weeks after its launch.
SuperTIGER (Super Trans-Iron Galactic Element Recorder) is designed to measure the rare, heavy elements in cosmic rays that hold clues about their origins...
16.01.2020 | Event News
15.01.2020 | Event News
07.01.2020 | Event News
17.01.2020 | Life Sciences
17.01.2020 | Power and Electrical Engineering
17.01.2020 | Life Sciences