Eye microbiome trains

Eye microbiome trains immune cells to fend off pathogens

Microbe living on the surface of the eye protects cornea from infections.

Bugs in your eyes may be a good thing. Resident microbes living on the eye are essential for immune responses that protect the eye from infection, new research shows. The study, which appears in the journal Immunity, demonstrates the existence of a resident ocular microbiome that trains the developing immune system to fend off pathogens. The research was conducted at the National Eye Institute (NEI), part of the National Institutes of Health.

“This is the first evidence that a bacterium lives on the ocular surface long-term,” explained Rachel Caspi, Ph.D., senior investigator in NEI’s Laboratory of Immunology. “This work addresses a longstanding question about whether there is a resident ocular microbiome.”

For years, the ocular surface was thought to be sterile because of the presence of an enzyme called lysozyme that destroys bacteria, antimicrobial peptides, and other factors that rid the eye of microbes that may land from the air (or from our fingers) onto the surface of the eye.

Anthony St. Leger, Ph.D., research fellow in Caspi’s laboratory, was able to culture bacteria from the mouse conjunctiva, the membrane that lines the eyelids. He found several species of Staphylococci, which are commonly found on the skin, and Corynebacterium mastitidis (C. mast). But it wasn’t clear whether those microbes had just arrived on the eye and were en route to being destroyed, or whether they lived on the eye for extended periods of time.

The researchers found that C. mast, when cultured with immune cells from the conjunctiva, induced the production of interleukin (IL)-17, a signaling protein critical for host defense…..

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Source: Medical News Today

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