The human body is equipped with a sophisticated immune system that protects us from external threats. However, there are areas, such as the eye, that require additional protection due to their vulnerability. Recent research has shown that immune cells in the eye, previously thought to be dendritic cells, are actually T cells. This discovery sheds light on the immune response in the eye and opens up new possibilities for clinical applications.
Misclassification of immune cells
Traditionally, immune cells in the eye have been classified as dendritic cells based on static imaging. Dendritic cells are responsible for transferring antigens to other immune cells known as T cells, which trigger an immune response against foreign invaders. However, scientists have now realized that these cells in the eye are actually T cells themselves.
According to Scott Muller, an immunologist at the Peter Doherty Institute for Infection and Immunity in Melbourne, Australia, “By combining our recently developed imaging technique with other advanced analytical approaches, we were able to discover that a significant number of cells on the surface of a healthy cornea are actually T cells.”
The role of T cells in the cornea
The cornea is the transparent membrane of the eye and plays a crucial role in vision. It is responsible for two-thirds of the optical power of the eye. Immune responses in the cornea, such as inflammation, must be tightly controlled to maintain clear vision. Previous animal studies have shown that T cells play a protective role against eye infections in mice, and the researchers set out to find out if this was the case in humans.
Using an in vivo functional confocal microscopy technique that allows them to visualize living tissue at the cellular level, the researchers observed how T cells interact with dendritic cells and nerves in the corneal epithelium, its outer layer. They also found crawling macrophages and rare motile T cells patrolling the deeper layers of the cornea, known as the corneal stroma.
Understanding immune responses in the eye
The results of this study provide a deeper understanding of the immune cells present in the cornea and their role in defense against pathogens. In addition, the researchers studied the response of T cells to various stimuli, such as short-term contact lens wear and allergic eye diseases. They also studied how drugs can modulate the behavior of these immune cells.
Potential clinical applications
The non-invasive real-time imaging technique used in this study has the potential for direct application in clinics to assess immune responses and ocular health. Ocular immunologist Holly Chinnery of the University of Melbourne emphasizes the significance of this technique, stating that it “could be used in clinics directly to assess immune responses and eye health.”
However, further validation of the technique is required before it can be implemented into clinical practice. In the past, similar techniques have been used to monitor changes in the cornea after cataract surgery in people with diabetes who are prone to developing cataracts.
In conclusion, this pioneering study challenges previous ideas about immune cells in the eye and provides valuable insights into their role in defense against pathogens. The detection of T cells in the cornea opens new avenues for clinical application and evaluation of immune responses and ocular health.
