Researchers Develop Vaccine Candidates to Prevent Epstein-Barr Virus

A National Institutes of Health research team has determined how several antibodies induced by Epstein-Barr virus (EBV) block infection of cells grown in the laboratory. They then used the information to develop novel vaccine candidates that, in animals, elicited potent anti-EBV antibody responses that blocked infection of cell types involved in EBV-associated cancers. One of the vaccine candidates is designed to elicit antibodies to gH/gL on epithelial cells, and the other is designed to elicit antibodies to gH/gL and another viral protein, gp42. When tested on mice and monkeys, each experimental vaccine induced antibodies that potently inhibited epithelial cell fusion. However, the vaccine containing gp42 induced stronger B cell fusion inhibitor antibodies.

Currently, there is no licensed vaccine for EBV, a virus associated with certain cancers (nasopharyngeal and gastric) of epithelial cells, which form the lining of the body’s surfaces, as well as Birkitt and Hodgkin lymphomas, which are cancers of the immune system’s B cells. Worldwide, approximately 200,000 cases of EBV-associated cancers occur annually, resulting in 140,000 deaths.

Previous research to develop a vaccine focused on a viral surface protein, gp350, that the virus uses to enter B cells. However, EBV infects both B cells and epithelial cells that line the mouth and upper throat, the latter of which are usually infected after contact with saliva from an EBV-infected individual. The new vaccine candidates could prevent EBV from fusing with both epithelial cells and B cells, thus providing protection independent of cell type. The team is planning to further develop one of the vaccine constructs that can be tested in humans.