Project Summary/Abstract: Epstein-Barr virus (EBV) is a-herpesvirus that is ubiquitous in humans and infects epithelial cells and B cells. EBV typically causes mononucleosis in humans but is also oncogenic and is associated with a wide array of malignancies in humans including Burkitt lymphoma, Hodgkin Lymphoma, nasopharyngeal carcinoma (NPC), and gastric carcinoma. Recently we identified ephrin receptor tyrosine kinase A2 (EphA2), which binds the EBV encoded gH/gL, as the EBV epithelial entry receptor. EphA2 is a transmembrane receptor tyrosine kinase that functions in the regulation of cell growth, survival, angiogenesis, and migration. It is expressed in adult epithelial tissue such as gastric and oral epithelium. However, more recent studies and our data have shown that EphA2 may not be accessible in healthy epithelium for EBV infection. This indicates that EBV infection of the epithelium is a complicated process that has not been fully elucidated. In our proposed studies, we will investigate the mechanism of EBV infection of the epithelium using the Longnecker Laboratory's experience studying the mechanism of Herpes Simplex Virus (HSV) epithelial infection and studying EBV B cell and epithelial cell infection. For this proposal, in Aim 1, we intend to study the role of tight junctions in protecting normal epithelium from EBV infection. We also plan to study whether LPS derived from Helicobacter pylori (HP) plays a role in breaking tight junctions facilitating EBV infection since HP is considered a primary carcinogen in gastric cancer pathogenesis. In Aim 2, we will investigate whether polymorphisms in EphA2 have different affinities in binding to EBV gH/gL, signaling through EphA2 which may result in differences in the breakdown of TJs and altering EBV infection. In Aim 3, since inflammatory conditions such as gastritis and HP infection may increase the risk of for gastric cancer, we hypothesized that these conditions induce the expression of other receptor(s) or co-receptor(s) that aide in the entry of virus into healthy epithelium. When we compared gene expression in HP infected AGS cells and HP infected gastric tissue with that in control AGS cells or tissue without HP infection. We found 15 potential genes which are membranes proteins that were upregulated in HP infected cells. We plan to investigate if the encoded proteins regulate EBV infection positively or negatively. By investigating the mechanism how EBV entry into epithelial cells, we will better understand the viral-host interactions, cellular factors, and role of tissue damage, and inflammation in EBV infection of epithelial cells which will aide in development of novel treatments and prevention strategies EBV-related epithelial pathologies.