SATURDAY, 14 APRIL 2012
Their study, published in Nature, shows that individuals carrying a certain variant of the gene ifitm3 are more likely to be hospitalised when infected with flu. The most common variants of ifitm3 offer protection against the virus, but having a rare version of the gene increases susceptibility to infection.
The protein encoded by ifitm3 plays a crucial role in the immune response to viruses such as H1N1 (‘swine flu’) by preventing viruses from spreading throughout the lungs. If the IFITM3 protein is absent or incorrectly folded, viruses are able to spread freely. IFITM3 is clearly vital in protecting against disease but as first author of the study, Aaron Everitt, explains, “little is known about how it works in the lungs.”
To investigate the protective role of IFITM3, researchers removed the ifitm3 gene from mice before exposing the animals to flu virus. Not only did the knockout mice contract flu, they also displayed far more severe symptoms than mice with ifitm3. Based on this finding, the ifitm3 genes of 53 patients who had been admitted to hospital with flu were then sequenced; consistent with the mouse study, a significant number of the genes were found to be mutated.
This research gives a useful insight into IFITM3’s role in defending cells against viral infection. The research suggests that populations with reduced IFITM3 protein activity could be more susceptible to serious infection during a pandemic, such as with avian influenza virus or dengue virus.
Written by Mrinalini Dey