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Finding a vaccine for ocular herpes

April 24, 2018 | UCI Health
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Ibachir BenMohamed and his research group are working on a treatment of a more insidious manifestation of the herpes simplex type 1 virus: ocular herpes, which attacks the eye and can cause severe damage.

Ibachir BenMohamed, PhD, is fighting an eye disease that few people realize exists.

“When I tell people about my work developing a vaccine against herpes, they immediately think genital herpes,” said BenMohamed, immunologist and vaccinology expert at the UCI Health Gavin Herbert Eye Institute and professor of immunology at the UC School of Medicine.

BenMohamed and his research group are working on a treatment of a more insidious manifestation of the herpes simplex type 1 virus: ocular herpes, which attacks the eye and can cause severe damage.

Cornea at risk for scarring

An estimated 500,000 people in the United States suffer from ocular herpes, according to the National Institutes of Health. For many people it remains dormant. But when a virus attack is caught early, the blisters and lesions can be treated with forms of antiviral drugs, such as acyclovir, the same medication people use to fight their cold sores.

Left untreated, ocular herpes can scar the cornea, requiring a corneal transplant.

BenMohamed’s aim, working with a $6-million grant from the National Eye Institute, is to keep ocular herpes from occurring in the first place.

Herpes: a dormant virus

The vaccine won’t eliminate the virus, which lurks dormant in infected people and then occasionally breaks out during exposure to stress or after overexposure to sun.

Instead, the idea is to keep the virus contained in its lurking zone, the trigeminal ganglia located under the brain.

A side benefit of BenMohamed’s research: A vaccine also could prevent future cold sores and perhaps some forms of genital herpes as well.

Next step: human clinical trials

His team’s research recently reached a milestone: Last summer, their article on clinical trials in mice, showing the vaccine to be nearly 100 percent effective, was published in the Journal of Immunology. He also presented the research at the 13th World Congress on Infection and Prevention last December. 

The next step will be to seek permission from the U.S. Food and Drug Administration for a phase 1 safety trial of the treatment on humans.

What they have found is that certain white blood cells appear to block the virus from causing breakouts, BenMohamed said. People who are afflicted by ocular herpes appear to have too few of these cells, or the cells are less active — or perhaps both.

Virus can evade immune system

The vaccine is expected to boost the number or function of those white blood cells in afflicted people, but it alone won’t be enough. Another obstacle confronting researchers is the virus’ uncanny ability to evade the immune system.

The virus can outsmart the human body and can even attack and weaken the white blood cells intended to fight it at certain “immune checkpoints.”

A second arm of the group’s research involves finding a way to block that cell-weakening gene within the virus with monoclonal antibodies.

“We are trying to find those immune checkpoints. Once that’s done, those blocking antibodies will be combined with the vaccine,” BenMohamed said.

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