SUMMARY The long-term goals and objectives of this proposal is to investigate host and virological factors associated with oral transmission of Kaposi’s sarcoma-associated herpesvirus (KSHV) utilizing the closely related rhesus macaque rhadinovirus (RRV) infection of rhesus macaques (RM) model that parallels KSHV infection and pathogenicity in humans. Like KSHV, RRV is a gamma-2 herpesvirus that is closely related to KSHV at the genomic level, possessing essentially collinear genome organization. Pathologically, RRV closely resembles KSHV, as we have shown that intravenous (iv) inoculation of RRV can induce KSHV-like disease manifestations in RM co-infected with simian immunodeficiency virus (SIV). Similarly, RM are infected with RRV early in life, within the first 2 years, implying RRV infection mimics KSHV infection in children living in sub-Saharan Africa, where KSHV is acquired early in life. Here, we will determine whether RRV can cross the oral mucosa to establish infection, and identify the in vivo conditions necessary. These first of kind studies for RRV will be performed in parallel with in vitro studies to interrogate viral glycoprotein receptor(s) density and cell types expressing the receptor(s) in different regions of the oral cavity, as a means to define the mechanism for transmission. Lastly, as we have created an infectious and pathogenic bacterial artificial chromosome (BAC) clone of wild type RRV (WT-RRVBAC) that provides a molecular genetic system to interrogate viral factors that are necessary for infection, we will undertake a molecular approach to interrogate viral encoded factors that facilitate KSHV infection across the oral mucosa. Specifically, we hypothesize that RRV envelope glycoproteins gB, gH, gL, gM and potentially gR8.1 are necessary for binding to receptors on susceptible cells and that KSHV glycoproteins gB, gH, gL, gM and gK8.1 can functionally substitute for RRV glycoprotein homologues. Hence, establishing this chimeric virus system will enable researchers and vaccinologists, the ability to target the viral glycoproteins for vaccine approaches in a nonhuman primate (NHP) model.

PROJECT NARRATIVE/RELEVANCE Individuals with an underlying HIV-infection have an increased risk of developing AIDS-related malignancies. Kaposi sarcoma-associated herpesvirus (KSHV) is the necessary causal agent for Kaposi's sarcoma and is a cofactor in B cell lymphoproliferative disorders observed in AIDS patients. Understanding how KSHV is transmitted amongst the population is a necessary first step in creating a vaccine to prevent the spread of KSHV worldwide. The results from the proposed studies utilizing the nonhuman primate model should help elucidate and define the mechanisms involved in KSHV transmission.