The eyes may be the windows to the soul, but they are also vulnerable access points for environmental pathogens. What’s more, under normal conditions, some of the most sensitive parts of the eye’s anatomy, such as the lens and retina, lack immune cells altogether. Until now, the mechanisms that control healing and resist infection in these eye tissues have remained a gray zone. However, a recent study has introduced a novel mechanism through which immune cells protect the eye.
Researcher Sue Menko and a team of scientists from Thomas Jefferson University have published new data that topples the decades-old dogma that the lens is devoid of immune cells. Instead, they demonstrated that in the event of corneal inflammation, an army of T-cells and other immune cells rush to the scene to help resolve tissue damage.
Menko and colleagues discovered these interactions in an animal model of uveitis, an inflammatory eye condition typically triggered by infection or injury. “In our previous study in which the cornea was wounded, we saw a small number of immune cells on the surface of the lens, acting almost like sentinels,” said Menko.
“In this case, it was like a battering ram. There were dozens of immune cells, and different types of them, including T-cells and macrophages. It’s clearly a robust immune response and could reflect in part that inflammation in uveitis is so severe.”
Fascinatingly, using high-powered fluorescence microscopy, the team observed that immune cells could infiltrate the thick lens capsule to initiate healing. After about a month, most immune cells had retreated from the lens tissue, but a few of them remained. Although their purpose is unclear, the researchers theorize that they may offer continued surveillance for future flare-ups.
These new findings form the basis for a myriad of follow-up studies involving other pathologies affecting the lens, such as glaucoma.