Respiratory syncytial virus (RSV) is the most serious cause of lower respiratory tract infections in infants, young children and immunocompromised individuals. It is increasingly being recognised as a serious respiratory pathogen in the elderly. A hallmark of RSV is the lack of an adequate long lasting immune response to the virus, resulting in multiple infections throughout life. There are no vaccines or efficacious therapeutics for RSV.
RSV encodes two small proteins which suppress antiviral responses of the host cell, including interferon induction and signalling. These proteins are termed non-structural proteins (NS1 and NS2) because they appear not to be packaged with budding virions. One of these proteins, NS1, appears to be the major culprit in terms of host cell response suppression, which it achieves through post-translational mechanisms. For instance it is proposed that NS1 acts as an E3 ligase. NS1 would appear to be a potential target for development of therapeutics for RSV. Accordingly, we have adopted a proteomic approach in conjunction with reverse viral genetics for identification of molecular targets for NS1 and to define its mechanism of action. Of interest is that NS1 appears to sustain the survival of proteins within the infected cell in order to suppress apoptosis on one hand whilst suppressing interferon responses on the other hand. These findings suggest that in part NS1 does not function to subject its targets to degradation. Processes used to achieve this novel marriage of reverse viral genetics and high-performance proteomic technologies will be presented in addition to the data supporting the observations cited above. In particular, a method for identification of protein regulation at a specific proteoform level will be presented.