Scientists have uncovered the structure of 1918 flu virus
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《英国医生杂志》
London
Scientists at the Medical Research Council have discovered the crucial structural changes the avian influenza virus underwent that resulted in its killing 20 million people worldwide in 1918—more people than were killed in the first world war and making it the largest pandemic in history.
The study, published last week in the online version of Science (5 February; www.sciencemag.org/sciencexpress/recent.shtml), found that subtle alterations to the shape of a protein molecule, called haemaglutanin (HA), on the virus allowed transmission from birds to humans, among whom it spread rapidly to infect an estimated billion people—half the world's population at the time.
The haemaglutanin molecule protrudes from the surface of the virus as a series of spikes and enables it to lock on to receptors on the surface of cells in the body. It then gains entry into the cell to infect it.
Human and bird virus haemaglutanins interact with different receptors, which means that bird viruses are normally unable to be transmitted to humans. But in the 1918 virus the shape of the haemaglutanin changed subtly, giving it the capability to attach to receptors in human cells as well as bird cells. This structural change first allowed bird to human and then human to human transmission, resulting in the pandemic.
The team, from the council's National Institute for Medical Research, pieced together the haemaglutanin gene of the 1918 virus from samples from the body of an Inuit woman buried in the Alaskan tundra and from preserved samples from US soldiers who fought in the first world war. They then used x ray crystallography to determine the three dimensional structure of the haemaglutanin.
All the devastating flu pandemics of the last century were caused by viruses that came from birds, such as Spanish flu in 1918, Asian flu in 1957, and Hong Kong flu in 1968. Unfortunately this research will not have any immediate impact on the outbreak of chicken flu currently unfolding in east Asia. In this outbreak the virus has been transmitted from birds to humans but has not yet adapted for human to human transmission.
Nurses care for victims of the 1918 influenza epidemic in canvas tents in Lawrence, Massachusetts
Credit: HULTON GETTY
The study's lead researcher, John Skehel, said, "This paper is important because of the knowledge it brings about how these viruses, which originate in birds, can jump to humans. This allows us to track and monitor the changes in the virus for public health purposes."(Debashis Singh)
Scientists at the Medical Research Council have discovered the crucial structural changes the avian influenza virus underwent that resulted in its killing 20 million people worldwide in 1918—more people than were killed in the first world war and making it the largest pandemic in history.
The study, published last week in the online version of Science (5 February; www.sciencemag.org/sciencexpress/recent.shtml), found that subtle alterations to the shape of a protein molecule, called haemaglutanin (HA), on the virus allowed transmission from birds to humans, among whom it spread rapidly to infect an estimated billion people—half the world's population at the time.
The haemaglutanin molecule protrudes from the surface of the virus as a series of spikes and enables it to lock on to receptors on the surface of cells in the body. It then gains entry into the cell to infect it.
Human and bird virus haemaglutanins interact with different receptors, which means that bird viruses are normally unable to be transmitted to humans. But in the 1918 virus the shape of the haemaglutanin changed subtly, giving it the capability to attach to receptors in human cells as well as bird cells. This structural change first allowed bird to human and then human to human transmission, resulting in the pandemic.
The team, from the council's National Institute for Medical Research, pieced together the haemaglutanin gene of the 1918 virus from samples from the body of an Inuit woman buried in the Alaskan tundra and from preserved samples from US soldiers who fought in the first world war. They then used x ray crystallography to determine the three dimensional structure of the haemaglutanin.
All the devastating flu pandemics of the last century were caused by viruses that came from birds, such as Spanish flu in 1918, Asian flu in 1957, and Hong Kong flu in 1968. Unfortunately this research will not have any immediate impact on the outbreak of chicken flu currently unfolding in east Asia. In this outbreak the virus has been transmitted from birds to humans but has not yet adapted for human to human transmission.
Nurses care for victims of the 1918 influenza epidemic in canvas tents in Lawrence, Massachusetts
Credit: HULTON GETTY
The study's lead researcher, John Skehel, said, "This paper is important because of the knowledge it brings about how these viruses, which originate in birds, can jump to humans. This allows us to track and monitor the changes in the virus for public health purposes."(Debashis Singh)