(567v) Influenza A H1N1: The Role of Inhibitory Proteins

In 2004, the US Institute of Medicine asserted that the world is teetering on the verge of a massive influenza outbreak. Consistent with this proclamation, the world has suffered the evolution of two influenza viruses in the first decade of the 21st century: Bird Flu and Swine Flue.

Emergence of a novel influenza A H1N1 viral strain has caused the first pandemic of the 21st century. Influenza viruses replicate by manipulating the host cell machinery, and the host in turn expresses defensive anti-viral restriction factors in response to viral infection. Recently, an attempt to identify the host cell restriction factors has led to the discovery of interferon induced transmembrane family proteins (IFITMs). In human three forms have been identified IFITM1, IFITM2 and IFITM3. These proteins have powerful antiviral effect and can block the replication of H1N1 influenza A virus. The interferon antiviral response is the first line of defense against viral infection in animal host. It has been found that depletion of IFITM3 decreases antiviral action of the interferon drastically (Brass et al. (2009), Cell 139(7) 1243-1254). However, the mechanism by which IFITM proteins inhibit the viral replication, that is whether they bind the viral protein or block the receptor site, is not yet known. This presentation will discuss some of the work carried out in understanding how the IFITMs function on molecular level and the kinetics of their biomolecular interactions and associated activities.