Navigation Links
Study of sugars on cell surface identifies key factor in flu infection
Date:1/6/2008

Scientists have identified a key factor that determines the ability of influenza viruses to infect cells of the human upper respiratory tracta necessary step for sustaining spread between people. The research, described in the January 6 online edition of Nature Biotechnology and funded by the National Institutes of Health (NIH), offers new insights into how the H5N1 avian flu virus currently circulating in birds would have to change in order to gain a foothold in human populations.

The H5N1 virus has infected several hundred people, but person-to-person transmission has been limited. To trigger a widespread outbreak, experts agree that the bird flu virus must infect the cells lining our noses and throats. We then would spread the virus to others through coughing or sneezing. The latest study, led by Ram Sasisekharan, Ph.D., of the Massachusetts Institute of Technology in Cambridge, refines this notion: The virus can gain access only through a subset of the sugar molecules coating the cells of our upper airways.

"Using an approach that combines experimentation and database analysis, Sasisekharans team has changed our view of flu viruses and how they must adapt to infect us, said Jeremy M. Berg, Ph.D., director of the National Institute of General Medical Sciences, the NIH component that supported the research. The work may improve our ability to monitor the evolution of the H5N1 virus and thwart potential outbreaks.

Chains of sugars called glycans sit on the surface of our cells and control the gates through which different molecules enter. For a virus to gain access to a cell, proteins on the viruss surface must bind to certain glycans.

The binding protein for flu viruses is hemagglutinin. The protein can vary with each flu strain and, as a result, latch on to glycans from different types of cells. While the protein from human-adapted flu viruses favors the sugars dotting the cells of the nose and throat, the one from bird flu viruses opts for glycans on cells deeper in the respiratory tract.

Sasisekharan noted that recent studies have shown that the hemagglutinin protein from bird flu viruses has on occasion attached to glycans of the upper airways. The surprising finding, he explained, is that the virus didnt always spread effectively.

This was a conundrum, said Sasisekharan.

To solve it, he and his team turned to the Consortium for Functional Glycomics (CFG), an initiative supported by NIGMS to explore the interactions between proteins and different types of sugars.

Mining data from the CFG glycan array, a tool for quickly screening protein-glycan binding preferences, Sasisekharan began to explore the structures of the different sugar chains coating upper respiratory tract cells.

We found remarkable diversity, he said. Even though these glycans are all linked the same way chemically, they have very different shapes.

According to the results, glycans of upper respiratory tract cells come in two main varieties: short and cone-shaped, and long and umbrella-shaped.

When the researchers combined this information with data from experiments and the glycan array, they found that the hemagglutinin protein from human-adapted flu viruses attached specifically to the long glycans of the upper respiratory tract. They also confirmed that the hemagglutinin from H5N1 viruses bound mainly to the cone-shaped glycans found in the lower respiratory tract.

These findings suggest that for the H5N1 bird flu virus to infect people and sustain its spread in humans, it must adapt so that it can latch onto the umbrella-shaped glycans of the upper respiratory tract.

Until now, we had an incomplete understanding of avian flu hemagglutinin and how the protein must adapt to humans, said Sasisekharan.

The new knowledge may unlock strategies for tracking mutations in the avian flu virus that allow it to bind to long glycans, point to new therapeutic targets for both seasonal and pandemic flu, and expand our basic knowledge of glycans and their diversity.


'/>"/>

Contact: Alisa Machalek
machalea@mail.nih.gov
301-496-7301
NIH/National Institute of General Medical Sciences
Source:Eurekalert

Related biology news :

1. Childhood obesity indicates greater risk of school absenteeism, Penn study reveals
2. A study by the MUHC and McGill University opens a new door to understanding cancer
3. Study begins to reveal clues to the cause and progression of sepsis
4. Clones on task serve greater good, evolutionary study shows
5. New study warns limited carbon market puts 20 percent of tropical forest at risk
6. New study examines how rearing environment can alter navigation
7. Study links cat disease to flame retardants in furniture and to pet food
8. New continent and species discovered in Atlantic study
9. Study shows link between alcohol consumption and hiv disease progression
10. Feeling hot, hot, hot: New study suggests ways to control fever-induced seizures
11. Study finds environmental tests help predict hospital-acquired Legionnaires disease risk
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/27/2017)... 2017  Catholic Health Services (CHS) has been ... (HIMSS) Analytics for achieving Stage 6 on the ... In addition, CHS previously earned a place in ... electronic medical record (EMR). "HIMSS Analytics ... EMR usage in an outpatient setting.  This recognition ...
(Date:3/23/2017)... Research and Markets has announced the addition of the "Global ... 2025" report to their offering. ... The Global Vehicle Anti-Theft System Market is ... next decade to reach approximately $14.21 billion by 2025. ... all the given segments on global as well as regional levels ...
(Date:3/20/2017)... March 20, 2017 At this year,s CeBIT Chancellor ... biometrics manufacturer DERMALOG. The Chancellor came to the DERMALOG stand together with ... this year,s CeBIT partner country. At the largest German biometrics company the ... fingerprint, face and iris recognition as well as DERMALOGĀ“s multi-biometrics system.   ... ...
Breaking Biology News(10 mins):
(Date:5/24/2017)... , May 23, 2017 As Ebola resurfaces ... with four deaths and 20 suspected cases now reported, a ... the PubMed database, showed a correlation between the 2014 and ... Replikin counts rose sharply in 2012-13, which preceded the 2014 ... in the Ebola gene Replikin counts in 2014-15, which again ...
(Date:5/23/2017)... (PRWEB) , ... May 23, ... ... offer an unlimited source of human cardiovascular cells for research and the ... methods makes it possible to generate large numbers of cardiomyocytes (hPSC-CMs). Due ...
(Date:5/23/2017)... Washington, USA (PRWEB) , ... May 22, 2017 ... ... SPIE Optics and Photonics 2017 in San Diego, California, this August will ... reality, solar fuels, and autonomous vehicles. , SPIE Optics and Photonics, the largest ...
(Date:5/23/2017)... ... 23, 2017 , ... Kathy Goin is joining myClin ... brings years of expertise in establishing and leading clinical operations at Sponsors including ... occupational therapist, through a variety of leadership roles in Clinical Operations, to her ...
Breaking Biology Technology: