MELBOURNE — Whether it’s a stray eyelash or dust causing irritation, the eyes are sensitive organs. However, the body does a good job at clearing away viral infections that target the eye, and a recent study finally explains how.
Researchers from The Peter Doherty Institute for Infection and Immunity show that the cornea — the transparent outer layer of your eye — uses T cells to monitor and eliminate viruses without harming a person’s vision.
The immune response in the cornea debunks a theory that T cells are not found in healthy corneas. The reason behind it is that the eyes create a weak immune response to avoid inflammation that would block sight.
To study the cornea, researchers used a multiphoton microscope to get an up-close view of cornea cells taken from the tissue of mice infected with the Herpes Simplex virus. The findings show that the eye produced long-living memory T cells and had them reside in the cornea. When exposed to infection, T cells travel across the eye to destroy the virus. Afterward, the T cells return to the cornea to prevent any future reinfection.
Moving images captured in the microscope reveal evidence of T cells patrolling the cornea. The discovery of immune cells in the cornea opens up doors to studying how eyes protect themselves from danger.
“Current understanding that T cells are not found in healthy corneas needs to be reconsidered, as our discovery shows tissue-resident memory T cells entering the cornea and remaining there for long periods,” explains lead author Scott Mueller, laboratory head at the Doherty Institute, in a statement.
He adds: “Our findings will improve the understanding of how to protect our eyes from infections that cause permanent blindness, such as Herpes Simplex Virus. This also has implications for understanding chronic conditions such as dry eye disease and common eye allergies where unwanted T cells might also cause disease.”
The study is published in the open access journal Cell Reports.