Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New mouse virus may help scientists better understand cruise ship epidemics

07.03.2003


A close relative of a common little-understood human virus that causes an estimated 23 million episodes of intestinal illness, 50,000 hospitalizations and 300 deaths each year has been discovered in mice. The finding by scientists at Washington University School of Medicine in St. Louis is reported in the March 7 issue of the journal Science.

Discovery of the new virus, known as murine norovirus 1 (MNV-1), may lead to a better understanding of its disease-causing cousins known as Norwalk viruses, or human noroviruses (HNVs). HNVs cause 90 percent of epidemic viral gastroenteritis worldwide, including those that sweep through cruise ships, nursing homes and military encampments causing debilitating diarrhea and vomiting.

"We know very little about human noroviruses because they cannot be grown in the laboratory or in animals," says study leader Herbert W. Virgin IV, M.D., Ph.D., professor of pathology and immunology and associate professor of molecular microbiology. "This new mouse virus will for the first time allow us to study this important class of human pathogens."



Virgin and colleagues discovered the virus in a strain of immune-deficient mice that were being reared for use in other research. When five of six mice died in one cage, the researchers decided to investigate. They took tissue from the dead mice and filtered and injected it into healthy mice, some of which had normal immunity and some of which were immune-deficient.

The mice with normal immunity remained healthy; the immune-deficient mice died. This indicated an infectious agent was present that healthy mice could resist but that killed immune-deficient mice. Further analysis identified the previously unknown norovirus.

The investigators then went a step further to determine what part of the mouse immune system is most important for fending off the infection.

The original mice had been engineered to lack two proteins: Rag (for recombination activating gene) and Stat1 (for signal transducer and activator of transcription 1).

Animals that lack the Rag do not develop T cells, B cells and antibodies. They therefore cannot recognize specific proteins, or antigens, that are found on viruses, bacteria and parasites. That is, the animals lack so-called adaptive immunity, which begins fighting viruses within a few days of infection.

Animals without Stat1 lack the other half of the immune system, known as innate immunity. Innate immunity kicks in immediately to fight infection, in part by causing cells to produce anti-viral molecules known as interferons. Mice that lack Stat1 cannot respond efficiently to interferon and lose most of their innate immune response. Mice deficient in both Rag and Stat1 have no adaptive and very limited innate immunity.

Virgin and colleagues discovered that mice with Stat1 but lacking Rag survived MNV-1 infection, while those lacking both Rag and Stat1 or Stat1 alone grew sick and died from it. They concluded that a strong innate immune response is essential for fighting off the virus.

"We were surprised to find that T cells or B cells weren’t needed to prevent lethal infection by this virus," Virgin says. "Mice without adaptive immunity seem to survive just fine."

Herpes and most other viruses kill mice that lack adaptive immunity, he adds.

The findings also have implications for commercial facilities that develop immune-deficient mice for use in research.

"Our data strongly suggest that infectious agents, including unknown infectious agents, should be considered when interpreting experiments that use immune-deficient mice," Virgin says. "Otherwise, one might conclude that an immune response was due to experimental conditions when in fact it may be due to a new pathogen."

Virgin also suggests that other scientists investigate unexplained deaths in immune-deficient mice.

"It may reveal other new viruses that might be useful for studying human biology and human infectious disease," he says.


Karst SM, Wobus CE, Lay M, Davidson J, Virgin IV, HW. STAT1-dependent immunity to a novel Norwalk-like virus. Science, March 7, 2003.

Funding from the National Institute of Allergy and Infectious Diseases supported this research.

The full-time and volunteer faculty of Washington University School of Medicine are the physicians and surgeons of Barnes-Jewish and St. Louis Children’s hospitals. The School of Medicine is one of the leading medical research, teaching and patient-care institutions in the nation. Through its affiliations with Barnes-Jewish and St. Louis Children’s hospitals, the School of Medicine is linked to BJC HealthCare.

Gila Z. Reckess | EurekAlert!
Further information:
http://medinfo.wustl.edu/

More articles from Health and Medicine:

nachricht Study suggests possible new target for treating and preventing Alzheimer's
02.12.2016 | Oregon Health & Science University

nachricht The first analysis of Ewing's sarcoma methyloma opens doors to new treatments
01.12.2016 | IDIBELL-Bellvitge Biomedical Research Institute

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>