This application is in response to Grand Opportunity (GO) RFA-OD-09-004 for Exploratory Research in the Development of Vaccines for AIDS-associated Malignancies. We will focus explore using the Epstein-Barr virus as a persistent vaccine vector for inducing life- long immune responses against HIV infection. Strategies for inducing life long, protective immunity against HIV infection remain elusive. Herpesviruses establish persistent, life-long infection in humans and are divided into three different classes based on their genetics and biology. Alpha (HSV), beta (CMV), and gamma-2 (RRV) herpesviruses are being studied as potential persistent vaccine vectors for inducing life-long immunity. Epstein-Barr virus is a gamma-1 herpesvirus that persists for life in an antigen presenting cell, i.e. B cell, and stimulates potent life long cellular and humoral immune responses. EBV infection upregulates many cell genes associated with antigen presentation and EBV carries very few immune evasion genes relative to other herpesviruses. EBV immortalized lymphoblastoid cell lines are commonly used in vitro for their immunostimulatory ability. EBV biology is different from other human herpesviruses, and EBV may provide unique advantages as a vaccine vector for inducing life-long immunity. All New and Old World non-human primates are naturally infected with herpesviruses closely related to EBV and in the same gamma-1, or lymphocryptovirus (LCV), genus. The LCV naturally infecting rhesus macaques (rhLCV) has been fully sequenced and has an identical repertoire of viral genes as EBV. Experimental rhLCV infection of rhesus macaques accurately reproduces EBV infection in humans, and we have recently developed a Bacterial Artificial Chromosome system for creating recombinant rhLCV. We will use this EBV animal model to evaluate the ability of recombinant rhLCV expressing SIV or HIV antigens to induce humoral and cellular immune responses to the gamma-herpesvirus vaccines. These pilot studies will explore a novel approach for inducing life-long persistent vaccine responses and will also provide important new insights for EBV biology. The data from these studies will provide the foundations for designing and testing the protective effect of a gamma-1 herpesvirus vaccine against SIV/SHIV challenge in the rhesus macaque animal model for EBV and HIV.
Strategies for inducing life long, protective immunity against HIV infection remains a major challenge. Herpesviruses establish persistent infection in humans and induce vigorous life-long cellular and humoral immune responses. These studies will determine whether the unique biology of persistent gamma-1 herpesvirsues, like Epstein-Barr virus and the EBV-related lymphocryptovirus that naturally infects rhesus macaques (rhLCV), will provide unique advantages as a persistent viral vaccine vector for inducing durable humoral and cellular immune responses to HIV and SIV.
