Ten-eleven translocation 2 (TET2) is an enzyme that plays a crucial role in the epigenetic regulation of gene expression within cytotoxic T lymphocytes (CD8+ T cells). Specifically, it functions as a dioxygenase that catalyzes the conversion of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC). This is a key step in DNA demethylation, a process essential for altering gene expression patterns. For example, during an infection, TET2 helps CD8+ T cells remodel their DNA methylation landscape, enabling them to express genes needed for effector functions like cytokine production and cytolytic activity.
The proper functioning of this enzymatic activity is paramount for effective anti-tumor and anti-viral immunity. Studies have shown that loss or dysfunction of this epigenetic regulator in CD8+ T cells can lead to impaired effector responses, reduced control of infections, and diminished anti-tumor activity. Furthermore, its activity has been linked to the differentiation and maintenance of memory CD8+ T cells, ensuring long-term protection against previously encountered pathogens or cancer cells. Historically, its role in hematopoiesis was first recognized, but subsequent research has highlighted its significance in the adaptive immune system.
