Longitudinal epitope-level profiling of the antigenic determinants of the antibody response against EBV in recently infected children with and without HIV - Epstein-Barr virus (EBV) is a ubiquitous oncogenic virus of major concern to U.S. public health. EBV-associated acute infectious mononucleosis (AIM) is rising in incidence in the United States, and EBV drives cancers and autoimmune diseases that affect Americans across the lifespan. After initial infection, EBV enters latency to evade the host immune system, but suppression of immunity can result in viral reactivation and play a role in oncogenesis. Such events account for over 200,000 incidents of EBV-associated cancers, and ~200,000 deaths annually worldwide. A current key U.S. health challenge is HIV-1 co-infection, which increases the risk of EBVassociated malignancies such as lymphomas even among people living with HIV on antiretroviral therapy. Despite decades of U.S.-driven research toward an EBV vaccine, how the early immune system establishes EBV latency remains an understudied gap that directly limits vaccine design efforts intended to protect U.S. children and immunocompromised populations. Our overall objective is to define the humoral immune response during primary EBV infection using VirScan Phage Immunoprecipitation and Sequencing (PhIP-Seq) to map publicly targeted epitopes of the EBV proteome, generating data to directly inform U.S. vaccine development. Our central hypothesis is that the antibody response to primary EBV infection in children is sufficient to drive viral latency but is more heterogeneous than those seen in adults, and the response will refine over time toward immunodominant proteins; epitopes critical for early control may be lost in adults through immune escape, and HIV co-infection will sustain reduced antibody targeting due to immunosuppression, which is a mechanism directly relevant to the U.S. HIV infected population. Since EBV infection occurs early in life, the primary antibody response must be characterized longitudinally in a pediatric cohort also infected with HIV, which is a resource not available within the U.S. Our laboratory holds a unique, archived longitudinal serum collection from 287 Zambian children followed from birth to age 3, about half HIV-positive, and half seroconverting for EBV and 90 seroconverting for KSHV. Thus, this collection of samples provides an unmatched opportunity to address all our objectives with the necessary statistical power and sampling density to allow our findings to be translated to U.S. pediatric and HIV-positive populations. We will: (1) longitudinally define the antibody repertoire against EBV during primary infection and two subsequent timepoints over 6 months, with and without HIV co-infection, and (2) determine how KSHV infection affects the humoral response to EBV at 3 months before, at, and 3 and 6 months after KSHV seroconversion. Completion of this proposal will provide the first longitudinal, high-resolution mapping of the initial antibody response to EBV, a pathogen that infects over 95% of Americans and drives a growing US burden of malignancies, acute infectious disease, and autoimmune disease. By identifying protective epitopes, this work will directly guide the vaccines and antibody-based interventions needed to reduce that burden in the US.
