Cyclosporine is commonly used topically to treat certain eye conditions. Which of the following is a known mechanism of action for cyclosporine?

Cyclosporine is primarily known for its ability to modulate immune responses, and its mechanism of action involves the inhibition of T-cell activation. By binding to the cytoplasmic protein cyclophilin within T-cells, cyclosporine forms a complex that inhibits calcineurin, a phosphatase that is crucial for the activation of T-cells and the subsequent production of interleukin-2 (IL-2) and other cytokines. This reduction in cytokine production leads to decreased T-cell proliferation and activation, which is beneficial in conditions where excessive immune response is a factor, such as in certain inflammatory eye conditions.

In the context of eye conditions, this mechanism helps reduce inflammation and is widely leveraged to treat conditions like dry eye, particularly in the formulation of Restasis, which is used to manage chronic dry eye associated with ocular inflammation. By focusing on T-cell activation, cyclosporine effectively addresses the underlying immune response that contributes to these eye conditions, thus making it an invaluable therapeutic agent in ophthalmology.