Thursday, May 5, 2022 (HealthDay News) — Two experimental vaccines show promise in protecting against infection with the “mono” virus, which also causes cancer and has been implicated as a potential trigger for multiple sclerosis, according to a new paper.
The vaccines, which have only been tested on animals to date, block two pathways by which Epstein-Barr virus (EBV) takes root inside the body, said lead researcher Dr. Gary Nabel, president and CEO of ModeX Therapeutics, a small biotech startup in Natick. collective.
Preventing Epstein-Barr is difficult because it takes place in two types of cells — immune B cells that produce antibodies, and epithelial cells that line the body’s interior and exterior surfaces, Nabel said.
These new vaccines are genetically designed to stimulate an immune response that would prevent infection from both types of cells, Nabel said.
“This gives us an opportunity to curb any foothold the virus can take to establish itself in the body,” Nabeul said. “That’s why we think this is a worthwhile approach, because we’ve essentially isolated two essential entry proteins for the virus, and we can block its ability to enter cells and cause infection.”
Currently, there is no approved vaccine to prevent the Epstein-Barr virus, which has infected more than 95% of adults worldwide, the researchers said in background notes.
Epstein-Barr is primarily known to be the cause of mononucleosis.
“It infects the body’s B cells, the antibody-producing cells, and causes these cells to multiply abnormally,” Nabel said. “You get a lot of infections, you get a lot of immune dysregulation. That’s why people feel so vulnerable. That’s why it takes months to get over. That’s why you get a severe infection with sore throat symptoms and upper respiratory symptoms, and these systemic symptoms that lead to mono infection.
But Nabeul said EBV was also the first human virus linked to cancers, particularly lymphomas and stomach cancer. The virus causes more than 200,000 cases of cancer each year.
Recently, researchers also learned that a person’s risk of developing multiple sclerosis (MS) is 32 times higher if they develop Epstein-Barr, according to a study published in Science in january.
EBV is thought to trigger MS in some people by tricking the immune system into attacking nerve cells in the body, according to another study published in January. temper nature.
The experimental vaccines work by genetically fusing two different attachment proteins — the switches that allow EBV to enter B cells and epithelial cells — into a common particle called ferritin, Nabel said.
Nabeul said ferritin’s usual job is to transport iron in the bloodstream, but genetic engineering gives it an additional purpose.
“It serves as a vector, where we can basically decorate the outside of the particle with viral proteins,” Nabel said. The immune system sees the viral infection proteins and mounts a response that theoretically protects against future infection with the real virus.
Vaccines led to robust antibody responses in mice, ferrets and monkeys, according to a new report published May 4. Translational Medicine Sciences.
The vaccines have also been shown to prevent the development of lymphomas in “humanized” mice – rodents grafted with human stem cells.
Nabeul said the researchers hope to begin human clinical trials of the vaccines within a year. However, it is important to note that results obtained from animal studies are not always replicated in humans.
Effective EBV vaccines will be key to ultimately establishing the link between the virus and multiple sclerosis, said Bruce Bebeau, executive vice president of research programs for the National Multiple Sclerosis Society.
“In order to establish causation, there is only one trial left. That trial is to get a vaccine and spread the vaccine, and then see if it can prevent multiple sclerosis over a period of time,” Bebeau said. “We have everything we need to know now to justify investing in this type of trial, once we have a safe and effective vaccine.”
This study was funded by Sanofi, one of the pharmaceutical companies that is developing the vaccine.
The US National Institutes of Health has more about the Epstein-Barr virus and multiple sclerosis.
SOURCES: Gary Nabel, MD, PhD, president and CEO, MODEX Therapeutics, Natick, Mass; Bruce Bebeau, Ph.D., Executive Vice President for Research Programs, National Multiple Sclerosis Society; Translational Medicine SciencesMay 4, 2022