The virus that 95% of people carry all their lives and is sometimes associated with serious diseases. The first human antibody capable of blocking the virus, developed by US researchers

An extremely widespread virus, which most people contract without knowing, remains in the body for life. Although most of the time it does not cause problems, in certain situations it is associated with serious diseases. According to estimates, the Epstein-Barr virus infects the majority of the population worldwide and is associated with multiple sclerosis or several types of cancer. US researchers have now identified human antibodies that prevent this virus from entering immune cells.

A new strategy based on monoclonal antibodies stopped Epstein-Barr virus (EBV) infection in preclinical models, reports News.ro. More precisely, American researchers have developed a human monoclonal antibody that managed to block the viral infection in an experimental model, opening the prospect of preventive therapies for high-risk patients.

A team from the Fred Hutch Oncology Center in Seattle, United States, announced that it had obtained human monoclonal antibodies capable of preventing the virus from entering the cells of the immune system. EBV is estimated to infect approximately 95% of the world's population and is associated with several types of cancer, neurodegenerative diseases and other chronic conditions.

To obtain these antibodies, the researchers used a genetically modified mouse model that carries human genes for the antibodies. The objective was to identify fully human monoclonal antibodies, in order to avoid immune reactions against the administered antibodies, frequent reactions when antibodies from other species are used.

The team targeted two viral antigens on the surface of EBV: gp350, involved in binding the virus to cell receptors, and gp42, which allows the virus to enter human cells through a process called fusion. The researchers identified two monoclonal antibodies against gp350 and eight against gp42.

In the final stage of the study, one of the monoclonal antibodies directed against gp42 prevented EBV infection in mice with a humanized immune system, experimentally exposed to the virus. Another antibody, directed against gp350, provided partial protection. Further analysis identified vulnerable regions of the virus that could be useful for future vaccine development.

EBV and post-transplant complications

Epstein-Barr virus is a major problem for patients undergoing immunosuppressive treatments after transplantation. In the US, more than 128,000 people undergo organ or bone marrow transplants each year. Currently, there are no specific therapies to prevent EBV infection or reactivation in these patients.

A severe complication is represented by post-transplant lymphoproliferative disorders (TLPT), an aggressive type of lymphoma that occurs after immunosuppression and is, in most cases, associated with EBV infection that evolves uncontrollably. The prevention of EBV viremia – the presence of the virus in the blood – could reduce the incidence of TLPT and limit the need to decrease immunosuppression, contributing to maintaining graft function and improving patient outcomes.

The risk is increased both in patients who receive organs from donors previously exposed to EBV, and in those who have already had the infection, because immunosuppression can allow the latent virus to reactivate.

Children undergoing transplantation could particularly benefit from such therapy, as a greater proportion of them have not been previously exposed to the virus.

The researchers believe that in the future, administration of these monoclonal antibodies by infusion could prevent PTLD by blocking EBV infection and reactivation in high-risk patients.

The Fred Hutch Cancer Center in the USA has applied for intellectual property protection on the identified antibodies and is collaborating with academic research institutions and industry to develop a possible therapy for immunocompromised patients. Such a therapy would initially be evaluated for safety in healthy adult volunteers, and later in clinical trials in targeted patients.

The link between EBV and multiple sclerosis

Over 95% of adults worldwide are infected with the Epstein-Barr virus. The infection generally has few symptoms and persists in the body for life, but for a small part of people EBV is associated with serious diseases. For over 50 years, EBV has been recognized as the first virus proven to contribute to the occurrence of certain types of cancer, which is why it is classified as a group 1 carcinogen.

In recent years, strong evidence suggests that EBV plays an important role in the development of multiple sclerosis (MS), a disease in which the immune system attacks the brain and spinal cord. MS affects millions of people worldwide and is frequently diagnosed in young adulthood. The evolution is unpredictable, and the symptoms vary over time.

EBV infection is very common, but not all infected people develop multiple sclerosis. The risk is also influenced by genetic factors, sex, smoking, obesity and low levels of vitamin D. EBV appears to play an important role in the onset of the disease, but alone is not sufficient to trigger it. For multiple sclerosis to develop, other factors are involved, such as genetic predisposition and certain environmental factors.

Symptoms of EBV infection may include fatigue, fever, sore throat, enlarged lymph nodes in the neck, enlarged spleen, enlarged liver, and skin rash.

The question is whether preventing EBV infection could reduce the risk of multiple sclerosis. Developing a vaccine has proven difficult, in part because the virus hides inside cells and persists over the long term. There are currently no approved vaccines against EBV, and the impact of preventing infection on the risk of MS remains unclear.

The link between EBV and multiple sclerosis is one of the most active areas of research today. New strategies target either the cells infected with the virus or the development of vaccines or immunological therapies that interrupt the associated biological processes.

If these directions prove to be effective, the treatment of multiple sclerosis would no longer be limited to the reduction of symptoms, but could include interventions applied earlier in the evolution of the disease or even strategies to prevent its occurrence.