Bacteria living on the surface of the eyes have been discovered

Polit.<url> based on Gizmodo materials: Your Eyeballs May Be Covered in Disease-Fighting Bacteria

An international team of scientists led by Rachel Caspi from the US National Eye Institute has discovered that bacteria are able to live on the surface of the eyes. So far they have been found in experiments with laboratory mice, but scientists do not rule out that similar bacteria exist in humans and that they play a role in protecting the eye from pathogens.

Although bacteria live in many places of the human body, from the surface of the skin to the intestines, it was generally believed that the conjunctiva – the shell of the eye – is free of them. In the 1990s, reports began to arrive about the isolation of bacterial DNA from the surface of the eye, but the presence of DNA still does not serve as proof that bacteria live there permanently.

In the new experiment, the researchers tried to grow bacteria from material obtained from swabs from the cornea of mice. Usually the petri dishes remained empty. But one day scientists forgot one Petri dish with a nutrient medium for a week in an incubator, where a low oxygen content was maintained. When they remembered about it, it turned out that clusters of slow-growing bacteria were visible on the surface of the medium.

Scientists have determined that in front of them are Corynebacterium mastitidis bacteria, which are often found on human skin. But the shape of the bacteria was strange. Usually they look like sticks, but here they looked like long thin threads. The researchers suggest that this may be due to an unfavorable environment for the development of bacteria.

By studying mice with bacteria living on their conjunctiva, scientists found that these mice were less susceptible to eye infections. The tears of mice that had Corynebacterium mastitidis more effectively destroy pathogens: Candida albicans fungus and Pseudomonas bacterium.

In experiments on cell cultures, it was shown that Corynebacterium mastitidis bacteria induce the production of IL-17 molecule by mouse cells, which plays an important role in the immune response. Genetically modified mice that do not have this molecule are much more likely to suffer from conjunctivitis. When mice that did not have Corynebacterium mastitidis bacteria in their eyes received them, they began to produce more IL-17 and became resistant to eye infections.

Article by Leger et al. An Ocular Commensal Protects against Corneal Infection by Driving an Interleukin-17 Response from Mucosal γδ T Cells is published in the journal Immunity.

Portal "Eternal youth" http://vechnayamolodost.ru  13.07.2017