Human cytomegalovirus (HCMV) is a paradigm for viral immune evasion strategies yet, paradoxically, primary infection of immunocompetent individuals rarely causes serious disease and such primary infections are normally quickly resolved. In contrast, infection of individuals whose immune systems are compromised (such as HIV/AIDS patients and transplant patients) or immature (such as the foetus in utero) often leads to wide spread viral replication and dissemination and this can often be life threatening. Although the immune evasion mechanisms employed by HCMV in vitro are well documented, the effectiveness of these during primary infection in vivo is not absolutely clear but probably allow the pathogen to initially overcome primary immune responses and thus create a window of opportunity for the virus to replicate and disseminate to cell types efficiently enough for latency to be established. Such a strategy could be conceived to be optimal for a life-long persistent pathogen as unchecked viral replication, leading to host mortality, would clearly be a dead end strategy for any virus. However, the establishment of quiescence would also, in itself, be a biological dead end for the virus, unless it was able to reactivate and re-establish lytic infection in order to infect naïve individuals. Similarly, a fitting time for a comprehensive set of immunevasion functions to be employed by the virus would be during reactivation from latency; these would again create a window of opportunity for the virus to re-establish the production of new virions in the face of an existing and primed anti-viral immune response.
Our programme of research seeks to addressed a number of important questions concerning the immunobiology of HCMV both in lytic and during latent infection. With a particular focus on the generation, maintanance and funtion of memory CD4+ and CD8+ T cells and the immune evasion mechanism employed by the virus to modulate Natural Killer cell function.
Gavin M Mason, Sarah Jackson, Georgina Okecha, Emma Poole, J.G. Patrick Sissons, John Sinclair and Mark R Wills. 2013. Human cytomegalovirus latency-associated proteins elicit immune-suppressive IL-10 producing CD4+ T cells. PlosPathogens 2013;9(10):e1003635
Mason, G. M., E. Poole, J. G. Sissons, J. H. Sinclair, and M. R. Wills. 2012. Human cytomegalovirus latency alters the cellular secretome, inducing cluster of differentiation (CD)4+ T-cell migration and suppression of effector function. Proceedings of the National Academy of Sciences of the United States of America 4;109(36):14538-43.
Bennett NJ, Ashiru O, Morgan FJ, Pang Y, Okecha G, Eagle RA, Trowsdale J, Sissons JG, Wills MR(2010) Intracellular sequestration of the NKG2D ligand ULBP3 by human cytomegalovirus J ImmunolJul 15; 185(2): 1093-102