A New Antibody Strategy Against Epstein–Barr Virus

Edited and Approved by Stephen C. Rose, PhD, MS

Epstein–Barr virus is familiar even to people who do not recognize its name. It is the leading cause of infectious mononucleosis, often called mono, and about nine in ten adults have antibodies indicating current or previous infection. Many infections, especially in childhood, cause few recognizable symptoms. Once acquired, the virus can remain inactive in the body and sometimes reactivate. That persistence helps explain the interest in preventing infection before it becomes established. [1]

A new study in Cell Reports Medicine offers an early step toward that goal. Researchers developed human antibody candidates and tested whether they could protect mice carrying human immune cells against an experimental Epstein–Barr virus challenge. One candidate targeting a viral protein called gp42 protected these animals; an antibody targeting another protein, gp350, provided partial protection. This is preliminary laboratory and animal evidence, with human benefit still unproven. [2]

What the researchers actually tested

The scientists used genetically modified mice to generate antibodies with human antibody sequences. They isolated two candidates against gp350 and eight against gp42. A separate type of mouse, called a humanized mouse because it carries human immune cells, was used for protection experiments. These are two different roles for mice: discovering antibodies and testing their effects. [2]

In the challenge experiments, antibodies were administered 24 hours before virus was injected into the bloodstream. Researchers assessed infection using measures including viral DNA in the spleen. The timing is crucial: the experiment tested protection before exposure, not removal of an infection already established in a person. [2]

An encouraging result in an animal model earns a candidate further investigation. It does not supply a dose for people, establish long-term safety, or show how well protection holds up during ordinary exposure. Human immune cells make the model useful, but they do not turn the entire animal into a human immune system. The appropriate next question is which additional experiments would make a clinical trial both informative and justified.

Blocking a step the virus needs

B cells are immune cells that help produce antibodies. EBV, the abbreviation for Epstein–Barr virus, can infect them. One entry step depends on gp42 interacting with HLA class II, a protein complex on the cell surface. A 2024 study identified gp42 antibodies that interfered with receptor binding or the fusion process needed for entry. Their different effects showed why the precise place an antibody attaches matters. [3]

A monoclonal antibody is a preparation of copies of one selected antibody. Selecting a useful candidate requires more than showing that it sticks to a virus. It must interfere with something important. In the earlier experiments, an antibody that blocked fusion without blocking receptor binding was less effective at neutralizing infection than another candidate. Laboratory binding, fusion inhibition, and prevention of infection therefore answer related but distinct questions. [3]

This is also why a laboratory result needs careful wording. A measurement of viral entry is not automatically a measurement of symptoms, cancer prevention, or survival. Each outcome adds a separate question. A strong development program should connect the proposed mechanism to outcomes that patients would actually notice, while checking whether the intervention introduces problems of its own.

Why transplant medicine is part of the discussion

One possible setting for future prevention studies is organ transplantation. American Society of Transplantation guidance identifies recipients without prior EBV infection as an important risk group for early EBV-associated post-transplant lymphoproliferative disorders, or PTLD. These disorders involve abnormal growth of immune cells and can include lymphoma. New infection, sometimes transmitted through the donor organ, contributes to this risk. Some PTLD is EBV-negative, so EBV prevention could not be assumed to prevent every case. [4]

Existing care already includes strategies for detecting and managing these problems. The guidance discusses blood monitoring for EBV DNA in selected high-risk recipients, adjustment of immune-suppressing treatment, and therapies such as rituximab for appropriate diagnosed disease. A tissue biopsy remains central to diagnosing PTLD. A proposed preventive antibody would have to be evaluated alongside established care, with specialist decisions about each patient’s risks. [4]

For a future trial, the choice of participants would matter as much as the choice of antibody. Preventing first infection in someone who has never encountered EBV is a different objective from preventing complications in someone already infected. Combining those situations without a clear plan could make a result difficult to interpret. Researchers would also need to separate fewer positive viral tests from fewer serious illnesses.

How this differs from vaccination

Giving an antibody supplies a prepared immune protein, an approach called passive immunization. Vaccination asks the recipient’s immune system to produce its own response. These approaches raise different practical questions: how quickly protection begins, how long it lasts, whether repeat doses are needed, and how well someone with a weakened immune system responds. The most useful option could depend on the clinical setting rather than one approach being best for everyone.

A randomized vaccine trial published in 2007 illustrates why outcomes must be distinguished. It enrolled 181 healthy young adults without evidence of previous EBV infection. A gp350-based vaccine reduced infectious mononucleosis but did not prevent asymptomatic EBV infection. The estimated efficacy against mono was 78%, with a wide confidence interval, indicating substantial uncertainty about the precise size of the benefit. This was a vaccine study in people, separate from the new antibody experiments. [5]

That distinction is useful when reading headlines. Preventing illness while allowing infection could still be worthwhile, but it does not establish prevention of lifelong viral persistence. Conversely, reducing a laboratory marker needs follow-up to determine whether patients feel better or avoid serious disease. The phrase “works against EBV” is incomplete unless the report explains what was measured, in whom, and for how long.

The multiple sclerosis connection needs its own evidence

Interest in EBV also reflects its relationship with multiple sclerosis, or MS, a disease affecting the brain and spinal cord. A large observational study of US military personnel found that MS risk rose markedly after EBV infection. The sequence of infection followed by evidence of nerve injury supported a causal role for the virus. However, this study did not test an EBV antibody or vaccine. It cannot tell us whether either intervention prevents MS or treats existing disease. [6]

A convincing explanation for a disease can point toward prevention without settling the treatment question. The intervention might need to be given at a particular time, protect for a particular duration, or affect a process beyond viral entry. These are questions to investigate, not details that can be filled in by an exciting mechanism. People with MS should not interpret the mouse findings as evidence that an antibody treatment is ready for them.

What this means for readers today

A positive EBV antibody test does not by itself show that the virus is causing current fatigue or other symptoms. CDC guidance explains that certain antibodies persist for life and that elevated levels can remain for years without indicating recent infection. Clinicians interpret the pattern of results together with the illness being investigated. Past exposure alone is not a reason to pursue experimental treatment. [7]

For everyday prevention, CDC advises reducing saliva exposure, including avoiding shared drinks and utensils with someone who is infected. Its guidance reports no vaccine available to protect against EBV infection. [1] The new antibody research deserves attention because it provides a concrete candidate for further testing. Its eventual value will depend on demonstrating safe, durable protection and meaningful benefit in the people most likely to need it.

References

[1] Centers for Disease Control and Prevention. About Epstein-Barr Virus (EBV). Updated May 9, 2024. Accessed September 13, 2026.

[2] Chhan CB, Lang K, Davis AR, et al. Transgenic mouse-derived human monoclonal antibodies targeting EBV gp350 and gp42 provide basis for therapeutic development. Cell Reports Medicine. 2026;7(2):102618. doi:10.1016/j.xcrm.2026.102618.

[3] Bu W, Kumar A, Board NL, et al. Epstein-Barr virus gp42 antibodies reveal sites of vulnerability for receptor binding and fusion to B cells. Immunity. 2024;57(3):559–573.e6. doi:10.1016/j.immuni.2024.02.008.

[4] Allen UD, Preiksaitis JK; AST Infectious Diseases Community of Practice. Post-transplant lymphoproliferative disorders, Epstein-Barr virus infection, and disease in solid organ transplantation: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice. Clinical Transplantation. 2019;33(9):e13652. doi:10.1111/ctr.13652.

[5] Sokal EM, Hoppenbrouwers K, Vandermeulen C, et al. Recombinant gp350 vaccine for infectious mononucleosis: a phase 2, randomized, double-blind, placebo-controlled trial to evaluate the safety, immunogenicity, and efficacy of an Epstein-Barr virus vaccine in healthy young adults. Journal of Infectious Diseases. 2007;196(12):1749–1753. doi:10.1086/523813.

[6] Bjornevik K, Cortese M, Healy BC, et al. Longitudinal analysis reveals high prevalence of Epstein-Barr virus associated with multiple sclerosis. Science. 2022;375(6578):296–301. doi:10.1126/science.abj8222.

[7] Centers for Disease Control and Prevention. Laboratory Testing for Epstein-Barr Virus (EBV). Updated April 10, 2024. Accessed September 13, 2026.