An insect cell-derived extracellular vesicle-based gB vaccine elicits robust adaptive immune responses against Epstein-Barr virus.

Epstein-Barr virus (EBV), the first identified human tumor virus, is implicated in various human malignancies, infectious mononucleosis, and more recently, multiple sclerosis. Prophylactic vaccines have the potential to effectively prevent EBV infection. Glycoprotein B (gB) serves as the fusogen and plays a pivotal role in the virus entry process, making it a critical target for EBV vaccine development. Surface membrane proteins of enveloped viruses serve as native conformational antigens, making them susceptible to immune recognition. Utilizing lipid membrane-bound viral antigens is a promising strategy for effective vaccine presentation in this context. In this study, we employed a truncated design for gB proteins, observing that these truncated gB proteins prompted a substantial release of extracellular vesicles (EVs) in insect cells. We verified that EVs exhibited abundant gB proteins, displaying the typical virus particle morphology and extracellular vesicle characteristics. gB EVs demonstrated a more efficient humoral and cellular immune response compared with the gB ectodomain trimer vaccine in mice. Moreover, the antisera induced by the gB EVs vaccine exhibited robust antibody-dependent cytotoxicity. Consequently, gB EVs-based vaccines hold significant potential for preventing EBV infection and offer valuable insights for vaccine design.