Health

As links to MS deepen, researchers speed up efforts to develop Epstein-Barr . vaccine


You’ve probably never heard of the Epstein-Barr virus. But it knows all about you.

Chances are, it’s living inside of you right now. About 95% of American adults infected at some point in their lives. And once infected, the virus stays with you.

Most viruses, such as the flu, just come and go. A healthy immune system will attack them, destroy them and prevent them from making you sick again. Epstein-Barr and its cousins, including the viruses that cause chickenpox and herpes, can hibernate inside your cells for decades.

Blossom Damania, a virologist at the University of North Carolina-Chapel Hill, said the family of viruses had “evolved with us for millions of years”. “They know all your body’s secrets.”

Although childhood Epstein-Barr infection is usually mild, exposure in adolescents and young adults can lead to transmission. mononucleara week-long illness 125,000 Americans a year, causing sore throats, swollen glands, and extreme fatigue. And while Epstein-Barr spends most of its time sleeping, it can awaken during times of stress or when the immune system is down. Those reactivations are linked to a long list of serious health conditions, including certain types of cancer and autoimmune disease.

Scientists have spent years trying to develop a vaccine against Epstein-Barr, or EBV. But recently, several leaps and bounds in medical research have provided more urgency to the quest – and more hope of success. In the past year alone, two vaccine testing efforts have entered human clinical trials.

What’s changed?

First, the Epstein-Barr virus has been shown to pose a greater threat. New research strongly links it to multiple sclerosisor MS, a potentially disabling chronic illness more than 900,000 Americans and 2.8 million people worldwide.

The January issue of Science magazine published results from a 20 year research milestone out of 10 million military supplies Strongest proof that Epstein-Barr can trigger MS. New research shows that people infected with Epstein-Barr are 32 times more likely to develop MS than those who are not infected.

And to shed light on the mechanisms that might explain that correlation, a separate team of scientists has published a study. in nature describes how the virus can induce an autoimmune response that leads to MS. This disease usually occurs between 20 and 40 years old, which disrupts communication between the brain and other parts of the body and is often marked by recurrent episodes of extreme fatigue, blurred vision, muscle weakness, and difficulty with balance and coordination. At its worst, MS can lead to impaired speech and paralysis.

Amplify that newfound urgency, some new research suggest that Epstein-Barr reactivation the virus is also implicated in some cases long covida poorly understood condition in which patients experience persistent symptoms that often resemble mononucleosis.

Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine. Hotez co-created a cheap, patent-free covid vaccine called Corbevax.

Some researchers question the need for a vaccine that targets a disease like MS that, while debilitating, remains relatively rare.

Dr Ralph Horwitz, a professor at Temple University Lewis Katz School of Medicine, said removing Epstein-Barr would require vaccination of all healthy children despite their risk of developing cancer or multiple sclerosis. is small.

Before exposing children to the potential risks of a new vaccine, he said, scientists need to answer basic question about MS. For example, why would a virus that affects nearly everyone make a small percentage sick? And what role do stress and other environmental conditions play in that equation?

Immunologist Bruce Bebo, executive vice president of research at the National MS Society, says the answer is that Epstein-Barr is “necessary but not sufficient” to cause disease. “

Hotez said researchers can continue to probe the mysteries surrounding Epstein-Barr and MS even as vaccine efforts go on. More research is needed to understand which populations could benefit most from the vaccine, and once more is known, Hotez said, such a vaccine could be used for those diseases. most at-risk individuals, such as organ transplant recipients, instead of being universally used by all young people.

“Now that we know that Epstein-Barr has a very strong link to MS, we could save a lot of lives if we developed a vaccine now,” Damania said, “instead,” Damania said. for waiting 10 years” until all questions were answered.

Moderna and National Institute of Allergy and Infectious Diseases launched separate clinical trials of the Epstein-Barr vaccine in the past year. The Epstein-Barr vaccine is also in the early stages of testing in Opko Health, a biotech company based in Miami; Seattle’s Fred Hutchinson Cancer Center; and of California Hope City National Medical Center.

Scientists have been trying to develop a vaccine against Epstein-Barr for decades only to be stymied by the complexity of the virus. Dr. Jessica Durkee-Shock, clinical immunologist and principal investigator for the NIAID trial, said Epstein-Barr “was a master of immune system evasion.

Both MS and Epstein-Barr-associated cancers develop years after people are infected. So a trial designed to find out if a vaccine could prevent these diseases would take decades and cost a lot of money.

Moderna researchers are initially focusing on a more measurable goal: preventing mononucleosis, double the risk of multiple sclerosis. Mono only develops a month or so after people are infected with Epstein-Barr, so scientists won’t have to wait long for results.

Mono itself can be incredibly disruptive, keeping students out of class and rookies untrained for weeks. In about 10% of cases, paralysis fatigue lasts for six months or more. In 1% of cases, patients develop complications, including hepatitis and neurological problems.

Currently, clinical trials of the Epstein-Barr vaccine enroll only adults. “In the future, the perfect vaccine will be given to a small child,” says Durkee-Shock. “And it will protect them for life, and prevent them from getting mono or any other complications from the Epstein-Barr virus.”

NIAID vaccine, Tested for safety in 40 volunteers, built around ferritin, an iron storage protein that can be manipulated to display a viral protein important to the immune system. Like a Transformer cartoon, the ferritin nanoparticle self-assembles into what looks like a “small iron soccer ball,” says Durkee-Shock. “This method, in which multiple copies of the EBV protein is visualized on a single bead, has proven successful for other vaccines, including HPV and hepatitis B vaccines.

Moderna’s experimental vaccine, yes tested in about 270 people, which works like corporate covid footage. Both deliver fragments of the virus’ genetic information in molecules called mRNAs inside a lipid nanoparticle, or small fat bubble. Sumana Chandramouli, senior director and head of the infectious diseases research program at Moderna, said Moderna, which has dozens of mRNA vaccines in development, hopes to learn from each. and apply those lessons to Epstein-Barr.

“What the covid vaccine has shown us is that the mRNA technology is well tolerated, very safe and highly effective,” says Chandramouli.

But mRNA vaccines have limitations.

Although they have saved millions of lives during the covid pandemic, the levels of antibodies produced in response to the mRNA vaccine gradually decline after several months. It is possible that the rapid loss of antibodies is particularly relevant to the coronavirus and its rapidly evolving new strains, Hotez said. But if the reduced immunity inherent in mRNA technology, that could severely limit future vaccines.

The design of a vaccine against Epstein-Barr is also more complicated than that of covid. The Epstein-Barr virus and other herpesviruses are relatively large, four to five times larger than SARS-CoV-2, the coronavirus that causes genital warts. And while the coronavirus uses only one protein to infect human cells, the Epstein-Barr virus uses many, four of which are found in the Moderna vaccine.

Earlier experimental Epstein-Barr vaccines that target a viral protein have reduced rates of infectious mononucleosis but failure to prevent viral infection. According to Damania, a UNC virologist, targeting more viral proteins may be more effective at preventing infection.

“If you close one door, the other door stays open,” says Damania. “You have to stop infection in all cell types to have a successful vaccine against future infections.”

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