Epstein-Barr: Researchers step up efforts for vaccine against virus linked to mono, MS

Epstein-Barr: Researchers step up efforts for vaccine against virus linked to mono, MS

Maybe you haven’t heard of the Epstein-Barr virus. But it knows all about you.

Chances are, it’s living inside of you right now. related to 95% of American adults Sometimes in their lives are infected. And once infected, the virus stays with you.

Most viruses, like influenza, just come and go. A healthy immune system attacks them, kills them and prevents 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.

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

Although childhood Epstein-Barr infection is usually mild, exposure in adolescents and young adults can be contagious MononucleosisA week-long illness that causes illness 125,000 Americans A year, causing a sore throat, swollen glands and extreme fatigue. And while Epstein-Barr spends most of its time asleep, it can reawaken during times of stress or when the immune system is off its game. These reactivations are associated with a long list of serious health conditions Different types of cancer And Autoimmune disease.

Scientists have spent years developing a vaccine against Epstein-Barr, or EBV. But several recent leaps in medical research have given the search more urgency — and more hope for success. In just the past year, two experimental vaccine efforts have made it into human clinical trials.

What has changed?

First, the Epstein-Barr virus has been shown to pose a greater threat. New research strongly links it Multiple sclerosisor MS, a potentially disabling chronic disease that afflicts More than 900,000 Americans And 2.8 million people worldwide.

In January, the journal Science published results from a Landmark 20 years of research 10 million military personnel that offer Still stronger evidence That can trigger Epstein-Barr MS. New study shows people infected with Epstein-Barr are 32 times more likely to develop MS.

And shedding new light on the mechanisms that might explain that correlation, a separate group of scientists published a study in nature Describes how viruses can trigger an autoimmune response that leads to MS. Diseases, which usually strike in Age 20 and 40, disrupts communication between the brain and other parts of the body and is often characterized by recurring 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.

It is necessary to find new ones, to widen several things New research to recommend Reactivation of Epstein-Barr virus Also involved in some cases Long covidA little-understood condition in which patients experience chronic symptoms that often resemble mononucleosis.

And just as important for speed: Advances in vaccine science spurred by the pandemic, including the mRNA technology used in some Covid vaccines, could accelerate the development of other vaccines, including a vaccine against Epstein-Barr, said Dr. Peter Hotez, Ph.D. National School of Tropical Medicine at Baylor College of Medicine. Hotez co-developed a low-cost, patent-free Covid vaccine called Corbevax.

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

Lewis Katz School of Medicine Professor at Temple University. Eradicating Epstein-Barr would require vaccinating all healthy children, even if they are at low risk of developing cancer or multiple sclerosis, says Ralph Horvitz.

Before revealing the potential risks of a new vaccine to children, he said, scientists need answers Basic question Regarding MS, for example, why does a virus that affects almost everyone cause the disease in a small fraction? 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, said Epstein-Barr appears to be “necessary but not sufficient” to cause the disease, adding that the virus “could be the first in a string of dominoes.” ”

Hotez said researchers can continue to explore the mysteries surrounding Epstein-Barr and MS, and even pursue vaccine efforts. More studies are needed to understand which populations might benefit most from a vaccine, and once more is known, Hotez said, such a vaccine could potentially be used in patients at highest risk, such as organ transplant recipients, rather than administered universally. To all young people.

“Now that we know that Epstein-Barr is very strongly linked to MS, if we develop a vaccine now we can save a lot of lives,” Damania said, adding that “rather than waiting 10 years” until each question is answered.

modern And National Institute of Allergy and Infectious Diseases Over the past year, Epstein-Barr has launched separate clinical trials of the vaccine. Epstein-Barr vaccines are also in the early stages of testing Opco Health, a Miami-based biotech company; of Seattle Fred Hutchinson Cancer Center; and California City of Hope National Medical Center.

Scientists have sought to develop a vaccine against Epstein-Barr for decades only because of the complexity of the virus. Epstein-Barr is “a master of evading the immune system,” said Dr. Jessica Durkee-Schock, a clinical immunologist and principal investigator of the NIAID trial.

Both MS and cancers associated with Epstein-Barr develop many years after people become infected. So a trial designed to see if a vaccine can prevent these diseases would take decades and a lot of money.

Modern researchers are focusing primarily on a more easily measured goal: prevention of mononucleosis, which Doubles the risk of multiple sclerosis. People develop psychosis only a month or so after contracting Epstein-Barr, so scientists don’t have to wait long for results.

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

For now, clinical trials of Epstein-Barr vaccination are enrolling only adults. “In the future, a small child will be given the perfect vaccine,” Durkee-Schock said. “And that will protect them for life, and prevent them from getting mono or any other complications from the Epstein-Barr virus.”

NIAID vaccine, 40 volunteers are being screened for safety, built around ferritin, an iron-storage protein that can be used to display a key viral protein to the immune system. Like the cartoon Transformers, ferritin nanoparticles self-assemble to look like a “little iron soccer ball,” Durkee-Schock said. “This approach, in which many copies of the EBV protein are displayed on a single particle, has proven successful for other vaccines, including the HPV and hepatitis B vaccines.”

Modern experimental vaccines Tested in about 270 people, works like the company’s Covid shot. Both deliver snippets of the virus’s genetic information, or tiny bubbles of fat, in molecules called mRNA inside a lipid nanoparticle. Moderna, which has dozens of mRNA vaccines in development, hopes to learn from each and apply those lessons to Epstein-Barr, said Sumana Chandramouli, senior director and leader of Moderna’s infectious disease research program.

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

But mRNA vaccines have limitations.

Although they have saved millions of lives during the Covid pandemic, the levels of antibodies produced in response to mRNA vaccines decline after a few months. It’s possible that this rapid loss of antibodies is particularly related to the coronavirus and its rapidly evolving new strains, Hotez said. But if waning immunity is inherent to mRNA technology, it could seriously limit future vaccines.

Designing a vaccine against Epstein-Barr is more complicated than for Covid. Epstein-Barr virus and other herpes viruses are relatively large, four to five times larger than SARS-CoV-2, the coronavirus that causes Covid. And while the coronavirus uses only one protein to infect human cells, the Epstein-Barr virus uses many, including four in modern vaccines.

Earlier experimental Epstein-Barr vaccines targeting a viral protein reduced rates of infectious mononucleosis but Fails to prevent viral infections. Targeting multiple viral proteins may be more effective in preventing infection, said Damania, the UNC virologist.

“If you close one door, the other door is still open,” Damania said. “You have to block infection in all cells to have a successful vaccine that prevents future infections.”

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