Breakthrough in Combating Epstein-Barr Virus
Scientists have made a significant breakthrough in the fight against Epstein-Barr virus (EBV), a common and often persistent virus that affects nearly every American. Researchers from the Fred Hutchinson Cancer Center and the University of Washington in the United States have developed antibodies that can effectively disarm this incurable virus.
These antibodies are designed to bind to EBV particles, preventing them from attaching to crucial immune cells. In experiments with mice that have human-like immune systems, one of these antibodies was able to protect the animals from EBV infection. It is estimated that 95 percent of American adults are infected with EBV at some point in their lives.
Understanding Epstein-Barr Virus
EBV belongs to the herpes family of viruses and is most commonly known for causing infectious mononucleosis, also referred to as ‘mono’ or the ‘kissing disease.’ Most people contract EBV during childhood, often without experiencing any symptoms or with only mild ones. Once infected, the virus remains in the body for life, typically in a dormant state. However, it can sometimes reactivate, especially under conditions of stress or a weakened immune system.
Reactivation of EBV can lead to symptoms such as fatigue or swollen glands. In rare cases, chronic or severe reactivation has been linked to certain autoimmune diseases like multiple sclerosis or lupus, as well as specific cancers such as Hodgkin’s lymphoma or nasopharyngeal cancer, particularly in individuals with compromised immune systems.
Notably, EBV was the first virus discovered to cause cancer in humans. It is associated with approximately 358,000 new cancer cases and 209,000 deaths annually worldwide.
Advancements in Antibody Development
Andrew McGuire, a biochemist and co-researcher on the project, emphasized the importance of this discovery: “After many years of searching for a viable way to protect against Epstein-Barr virus, this is a significant stride for the scientific community and the people at the highest risk of complications from this virus.”
The research team aimed to develop fully human antibodies capable of preventing EBV infection, particularly in high-risk organ transplant patients who may develop deadly blood cancers if infected. They used genetically engineered mice that produced human antibodies instead of mouse antibodies. These mice were immunized with two EBV surface proteins, and then the cells that produced antibodies were collected and fused with cancer cells to create hybridomas—immortal cell lines that produce a single type of antibody.
Screening and Results
The researchers screened these antibodies to identify those that could block EBV from infecting B cells in laboratory settings. After immunizing the mice with two EBV proteins, gp350 and gp42, they identified two antibodies against gp350 and eight against gp42. These antibodies are fully human, making them potentially safer for patients compared to those derived from mice.
McGuire explained, “Finding human antibodies that block Epstein-Barr virus from infecting our immune cells has been particularly challenging because, unlike other viruses, EBV finds a way to bind to nearly every one of our B cells.”
The gp350 antibodies prevent the virus by blocking its attachment to a docking site on immune cells. The gp42 antibodies block a different docking site called HLA class II. Both mechanisms prevent the virus from entering cells.
Promising Outcomes
In the study, the gp42 antibody provided full protection to all the mice, with no signs of virus in their spleens. In contrast, the gp350 antibody offered only partial protection, with some mice still showing signs of infection. This makes the gp42 antibody a promising candidate for protecting high-risk patients, such as organ transplant recipients who are vulnerable to EBV-related cancers.
Currently, there are no approved vaccines or specific treatments for EBV. This discovery offers strong candidates for advancing human trials, potentially filling this gap for the first time.
Potential Impact on High-Risk Populations
Organ transplant recipients and individuals with weakened immune systems are particularly vulnerable to EBV-related cancers. The findings, published in Cell Reports Medicine, suggest a potential preventive treatment. Administering the gp42 antibody before illness could block EBV infection and prevent these cancers from developing.
The idea is that these antibodies could be given to the hundreds of thousands of people who undergo organ or bone marrow transplants each year. Because transplant patients require drugs that weaken their immune system, they become especially prone to EBV infection. If antibodies can block or reduce EBV infection early, it might lower the risk of developing conditions linked to EBV later in life.
