Epstein-Barr virus vaccine induces potent neutralising antibodies

Posted: 17 August 2015 | Victoria White

Researchers have developed an experimental, nanoparticle-based vaccine against Epstein-Barr virus that can induce potent neutralising antibodies in animals…

Researchers have developed an experimental, nanoparticle-based vaccine against Epstein-Barr virus that can induce potent neutralising antibodies in vaccinated mice and nonhuman primates.

Microscopic particles, known as nanoparticles, are being investigated as potential delivery vehicles for vaccines. The scientists’ findings suggest that using a structure-based vaccine design and self-assembling nanoparticles to deliver a viral protein that prompts an immune response could be a promising approach for developing an Epstein-Barr virus vaccine for humans.

First identified in 1964, Epstein-Barr virus is one of the most common human viruses in the world, infecting nine out of 10 people at some point in their lives. Most people experience no illness or only mild symptoms. Most commonly spread through saliva, it is best known as the major cause of infectious mononucleosis. Worldwide, Epstein-Barr virus is also associated with nearly 200,000 annual cases of cancer, including Burkitt and Hodgkin lymphoma, non-Hodgkin lymphoma, and stomach and nasopharyngeal cancers. Currently, there is no licensed vaccine to prevent Epstein-Barr virus infection.

Most efforts to develop a preventive Epstein-Barr virus vaccine have focused on glycoprotein 350, or gp350, a molecule on the surface of Epstein-Barr virus that helps the virus attach to certain immune system cells called B cells. Epstein-Barr virus gp350 is thought to be a key target for antibodies capable of preventing virus infection. Previously, scientists showed that vaccinating monkeys with gp350 protected the animals from developing lymphomas after exposure to a high dose of Epstein-Barr virus. However, in the only large human clinical trial of an experimental Epstein-Barr virus vaccine conducted to date, the Epstein-Barr virus gp350 vaccine did not prevent Epstein-Barr virus infection, but did reduce the rate of infectious mononucleosis by 78%.

New Epstein-Barr virus vaccine induced more neutralising antibodies than previous vaccine designs

To build on these findings, the team, which included researchers from the US National Institute of Allergy and Infectious Diseases (NIAID), designed a nanoparticle-based vaccine that expressed the cell-binding portion of gp350. In their testing, the experimental vaccine induced potent neutralising antibodies in both mice and nonhuman primates. Furthermore, the investigational vaccine induced up to 100-fold higher levels of neutralising antibodies in mice compared with previous vaccine designs by using structure-based design to precisely target the cell-binding site on gp350, the vulnerable part of the virus. The researchers believe the nanoparticle vaccine design could be used to create or redesign vaccines against other pathogens for which it has been difficult to induce effective immunity.

The research findings are published in Cell.