Penn Study Identifies How Ebola Virus Avoids the Immune SystemJanuary 28, 2009Researchers at the University of Pennsylvania School of Medicine have likely found one reason why the Ebola virus is such a powerful, deadly, and effective virus. Using a cell culture model for Ebola virus infection, they have discovered that the virus disables a cellular protein called tetherin that normally can block the spread of virus from cell to cell. "Tetherin represents a new class of cellular factors that possess a very different means of inhibiting viral replication," says study author Paul Bates, PhD, Associate Professor of Microbiology at the University of Pennsylvania School of Medicine. "Tetherin is the first example of a protein that affects the virus replication cycle after the virus is fully made and prevents the virus from being able to go off and infect the next cell." These findings appear online this week in the Proceedings of the National Academy of Sciences. When a cell is infected with a virus like Ebola, which is deadly to 90 percent of people infected, the cell is pirated by the virus and turned into a production factory that makes massive quantities on new virions. These virions are then released from that cell to infect other cells and promote the spreading infection. Tetherin is one of the immune system's responses to a viral infection. If working properly, tetherin stops the infected cell from releasing the newly made virus, thus shutting down spread to other cells. However, this study shows that the Ebola virus has developed a way to disable tetherin, thus blocking the body's response and allowing the virus to spread. "This information gives us a new way to study how tetherin works," says Bates. "Binding of a protein produced by Ebola to tetherin apparently inactivates this cellular factor. Understanding how the Ebola protein blocks the activity of tetherin may facilitate the design of therapeutics to inhibit this interaction, allowing the cell's natural defense systems to slow down viral replication and give the animal or person a chance to mount an effective antiviral response and recover." Previous research had found that tetherin plays a role in the immune system's response to HIV-1, a retrovirus, and that tetherin is also disabled by HIV. These new studies reveal that human cells also use this defense against other types of viruses, such as Ebola, that are not closely related to HIV-1. "Because we see such broad classes of viruses that are affected by tetherin, it's possible that all enveloped viruses are targets of this antiviral system," says Bates. "If so, then understanding how tetherin works and how viruses escape from the effect of tetherin will be very important." Rachel L. Kaletsky, Joseph R. Francica and Caroline Agrawal-Gamse of the University of Pennsylvania School of Medicine are co-authors of this study. This work was funded by the Public Health Service Grants and the Philip Morris External Research Foundation. The University of Pennsylvania Health System |
|||||||||||||||||||||
| Related Ebola Virus Current Events and Ebola Virus News Articles Scientists block Ebola infection in cell-culture experiments Researchers at the University of Texas Medical Branch at Galveston have discovered two biochemical pathways that the Ebola virus relies on to infect cells. Iowa State University researchers discover structure of key Ebola protein Research led by Iowa State University scientists has them a step closer to finding a way to counter the Ebola virus. Scientists discover new species of Ebola virus Scientists report the discovery of a new species of Ebola virus, provisionally named Bundibugyo ebolavirus, November 21 in the open-access journal PLoS Pathogens. Scientists uncover Ebola cell-invasion strategy University of Texas Medical Branch at Galveston researchers have discovered a key biochemical link in the process by which the Ebola Zaire virus infects cells - a critical step to finding a way to treat the deadly disease produced by the virus. Wildlife Conservation Society discovers 'Planet of the Apes' The world's population of critically endangered western lowland gorillas received a huge boost today when the Wildlife Conservation Society released a census showing massive numbers of these secretive great apes alive and well in the Republic of Congo. Scripps research scientists reveal key structure from ebola virus Described in the July 10, 2008 issue of the journal Nature, the research reveals the shape of the Ebola virus spike protein, which is necessary for viral entry into human cells, bound to an immune system antibody acting to neutralize the virus. Vaccine for Ebola virus One of the world's deadliest diseases, caused by the Ebola virus, may finally be preventable thanks to US and Canadian researchers, who have successfully tested several Ebola vaccines in primates and are now looking to adapt them for human use. Penn scientists find a protein that inhibits Ebola from reaching out to infect neighboring cells Scientists at the University of Pennsylvania School of Veterinary Medicine have identified a protein, ISG15, that inhibits the Ebola virus from budding, the process by which viruses escape from cells and spread to infect neighboring cells. Emerging infectious diseases on the rise: Next target 'hotspot' predicted It's not just your imagination. Providing the first-ever definitive proof, a team of scientists has shown that emerging infectious diseases such as HIV, Severe Acute Respiratory Syndrome (SARS), West Nile virus and Ebola are indeed on the rise. Study garners unique mating photos of wild gorillas Scientists from the Wildlife Conservation Society and Max Planck Institute for Evolutionary Anthropology have released the first known photographs of gorillas performing face-to-face copulation in the wild. This is the first time that western gorillas have been observed and photographed mating in such a manner. More Ebola Virus Current Events and Ebola Virus News Articles |
|||||||||||||||||||||
|
|||||||||||||||||||||
|
|||||||||||||||||||||