Featured Research

from universities, journals, and other organizations

Scientists Discover How Influenza Virus Becomes More Deadly

Date:
August 20, 1998
Source:
NIH-National Institute Of Allergy And Infectious Diseases
Summary:
Scientists supported by the National Institute of Allergy and Infectious Diseases (NIAID) have discovered why some influenza viruses are uncommonly deadly. In a paper published in the Aug. 18 issue of the Proceedings of the National Academy of Sciences USA, they describe an unusual molecular mechanism that amplifies the disease-causing power of influenza A virus.

Scientists supported by the National Institute of Allergy and Infectious Diseases (NIAID) have discovered why some influenza viruses are uncommonly deadly.

In a paper published in the Aug. 18 issue of the Proceedings of the National Academy of Sciences USA, they describe an unusual molecular mechanism that amplifies the disease-causing power of influenza A virus. This mechanism could be a new marker for scientists to examine when attempting to predict the potential for a newly emergent influenza A virus to cause a pandemic. Though still to be proved, their discovery may explain the longtime mystery of how the virus that caused the 1918 influenza pandemic caused more than 20 million deaths worldwide.

"Their findings point us in a direction to better understand the pathology of these more virulent influenza viruses," notes Dominick Iacuzio, Ph.D., program officer for influenza and related viral respiratory diseases at NIAID.

Influenza A viruses possess two surface proteins, hemagglutinin (HA) and neuraminidase (NA). To become infectious, the HA molecule must first be cut into two subunits that help the virus attach to human cells. Normally, influenza viruses remain confined to the respiratory tract because the protease enzymes that cleave HA are common in the lungs and trachea but not in other tissues.

Yoshihiro Kawaoka, D.V.M., Ph.D., and Hideo Goto, D.V.M., Ph.D., of the University of Wisconsin School of Veterinary Medicine in Madison, have discovered that this human influenza A virus is more virulent because it employs a more ubiquitous enzyme, plasmin, to help chop HA in two.

The scientists studied a virus descended from the strain that caused the 1918 pandemic and adapted to grow in mice. Through their experiments, they found that its NA molecule has two distinct structural features that enable it to bind and trap plasminogen, a precursor to plasmin, and thereby accelerate HA cleavage and promote widespread infection of cells.

The investigators tested 10 other human, swine and avian viruses, and found no evidence of the same mechanism at work, indicating that the ability to sequester plasminogen and thereby enhance HA cleavage was a unique property of this particularly virulent strain of human influenza A virus.

"This is a mechanism that we never knew existed in influenza viruses," says Dr. Kawaoka. "Now we have additional markers that we can look for when a peculiar outbreak of human or animal flu occurs," he adds. These two structural features of the NA molecule "should be considered when evaluating the health hazard posed by human influenza viruses," they write in their article. Any strain with an NA molecule possessing these two features, they add, "should be regarded as potentially dangerous."

Scientists have known for years that certain bacteria, such as group A streptococci, contain plasminogen-binding proteins that make it easier for these bacteria to infect tissues. But this is the first example, Dr. Kawaoka notes, of a virus that contains a plasminogen-binding protein. It is highly likely, he says, that such proteins will be found in other pathogenic viruses as well.

NIAID is a component of the National Institutes of Health (NIH). NIAID conducts and supports research to prevent, diagnose and treat illnesses such as HIV disease and other sexually transmitted diseases, tuberculosis, malaria, asthma and allergies. NIH is an agency of the U.S. Department of Health and Human Services.

References:

H Goto and Y Kawaoka. A novel mechanism for the acquisition of virulence by a human influenza A virus. Proceedings of the National Academy of Sciences USA 95:10224-28 (1998).

JK Taubenberger. Influenza virus hemagglutinin cleavage into HA1 and HA2: no laughing matter. Proceedings of the National Academy of Sciences USA 95:9713-15.

Note: Copies of the paper and the commentary can be requested directly from PNAS by calling (202) 334-2138.

Press releases, fact sheets and other NIAID-related materials are available via the NIAID Web site at http://www.niaid.nih.gov.


Story Source:

The above story is based on materials provided by NIH-National Institute Of Allergy And Infectious Diseases. Note: Materials may be edited for content and length.


Cite This Page:

NIH-National Institute Of Allergy And Infectious Diseases. "Scientists Discover How Influenza Virus Becomes More Deadly." ScienceDaily. ScienceDaily, 20 August 1998. <www.sciencedaily.com/releases/1998/08/980820080947.htm>.
NIH-National Institute Of Allergy And Infectious Diseases. (1998, August 20). Scientists Discover How Influenza Virus Becomes More Deadly. ScienceDaily. Retrieved September 18, 2014 from www.sciencedaily.com/releases/1998/08/980820080947.htm
NIH-National Institute Of Allergy And Infectious Diseases. "Scientists Discover How Influenza Virus Becomes More Deadly." ScienceDaily. www.sciencedaily.com/releases/1998/08/980820080947.htm (accessed September 18, 2014).

Share This



More Health & Medicine News

Thursday, September 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Artificial Sweetener Could Promote Diabetes

Artificial Sweetener Could Promote Diabetes

Newsy (Sep. 17, 2014) Doctors once thought artificial sweeteners lacked the health risks of sugar, but a new study says they can impact blood sugar levels the same way. Video provided by Newsy
Powered by NewsLook.com
Ebola Vaccine Trial Gets Underway at Oxford University

Ebola Vaccine Trial Gets Underway at Oxford University

AFP (Sep. 17, 2014) A healthy British volunteer is to become the first person to receive a new vaccine for the Ebola virus after US President Barack Obama called for action against the epidemic and warned it was "spiralling out of control." Duration: 01:02 Video provided by AFP
Powered by NewsLook.com
Obesity Rates Steady Even As Americans' Waistlines Expand

Obesity Rates Steady Even As Americans' Waistlines Expand

Newsy (Sep. 17, 2014) Researchers are puzzled as to why obesity rates remain relatively stable as average waistlines continue to expand. Video provided by Newsy
Powered by NewsLook.com
President To Send 3,000 Military Personnel To Fight Ebola

President To Send 3,000 Military Personnel To Fight Ebola

Newsy (Sep. 16, 2014) President Obama is expected to send 3,000 troops to West Africa as part of the effort to contain Ebola's spread. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins