PROJECT SUMMARY Epstein-Barr virus (EBV) is a herpesvirus that persists as a notable human pathogen with significant oncogenic potential that is related to its ability to establish lifelong latent infection within an immunocompetent host. Unlike for the vast majority of viruses, EBV-associated diseases are almost exclusively a consequence of latent infection instead of damage caused by virus replication. Latency poses significant problems, for example, in the development of effective anti-EBV therapeutics, since the majority of such compounds are designed to target viral polymerases and other proteins active only during virus replication; novel approaches are therefore needed to target latent EBV infection. Moreover, the ubiquitous nature of EBV (~95% infected by adulthood) and the highly evolved equilibrium that it has established within the human immune system, make development of an effective vaccine challenging. Both of these challenges could be greatly aided by a biologically accurate and tractable animal model of EBV infection, which currently does not exist. Surprisingly, several reports over the last decade have provided support for the laboratory rabbit as a model of EBV infection. In preliminary work, we have confirmed the most salient observations from these earlier studies, confirming that rabbits are indeed infectable, as indicated by persistence of the viral genome and expression of EBV genes associated with both the latent and productive stages of the virus lifecycle. However, several critical demonstrations are required to support authenticity of this model, and thus the extent to which it could be applied experimentally. In this application, we propose three specific aims to fill these gaps through complementary efforts by two senior investigators in the EBV field, and a third who has considerable expertise in the use of the rabbit as a model for virus infection and immune-related studies. Under Aim 1, Dr. Clare Sample will assess EBV infection in the epithelial cell component of the lifecycle, including the use of organotypic (raft) cultures of primary epithelium, a model she has developed and used to define EBV infection in human epithelium. Under Aim 2, Dr. Jeffery Sample will employ his expertise in the field of EBV latency to direct studies to elucidate whether establishment of a persistent infection in rabbit B cells is mechanistically comparable to the process that occurs in the human B-cell compartment. Finally, Dr. Neil Christensen, employing his expertise with the rabbit model will support work under Aims 1 and 2, and in Aim 3 will assess the humoral and cell-mediated immune responses to EBV infection in the rabbit, and whether they are comparable to key aspects of the adaptive immune response to EBV infection in the natural host. In summary, the proposed work will inform us whether the three basic host components that dictate EBV biology in its human host are equivalently functional in the rabbit: 1) Whether rabbit ep...