Daniel Shin, MD, PhD

T cells are an important component of the immune system that recognize and fight infections. However, studies have found that many of these T cells can also be reactive to our own body, and if they are triggered unnecessarily or excessively, these “self-reactive” T cells can attack our healthy tissues in the form of autoimmune diseases. Importantly, the lungs appear to be prone to attack by these self-reactive T cells. Thus, better understanding of how the body prevents lung autoimmunity remains a critical goal to human health. Recently, we found that when the lung is acutely injured, a specialized subset of T cells, called regulatory T cells, accumulate in the lung to limit the ongoing immune activity. Moreover, we detected a strong expansion in the number of regulatory T cells reactive to proteins specifically expressed on the damaged lung tissue. By examining whether these self-reactive regulatory T cells persist in the lungs to limit future injury, we hope to gain new insights into how the immune system protects against the development of autoimmune diseases.

Update: We previously found that after lung injury, a specialized subset of T cells, called regulatory T cells (Tregs), accumulate in the lung to help calm the immune response. These Tregs appear to recognize the body’s own lung proteins. This suggests that the immune system, by employing a group of Tregs that are self-reactive, can determine when its activity is damaging healthy tissue and prevent further injury. In the past year, we have tracked the formation and presence of these self-reactive Tregs following acute lung injury. Our findings indicate that T cells that are reactive to proteins in the lung appear to be heavily skewed towards Tregs for months after the initial injury to the lungs. Moreover, there is a notable population of these Tregs that remain in the lungs after prior injury. We are currently investigating the characteristics of these long-lived lung-reactive Tregs and the implications of their increased presence, particularly with regard to their protection against future injury to the lungs.