Maintenance of tolerance to self-antigens is essential for the prevention of autoimmunity. This process is known to involve specific regulatory T cells (Treg) and the expression of the forkhead family transcription factor, FOXP3.

FOXP3 is a “sufficient” regulator of the development and function of peripheral Treg cells, but the molecular mechanisms of FOXP3-mediated immunological regulation are still poorly understood.

Mutations in the forkhead domain of FOXP3 are found in the fatal recessive disorder, “X-linked autoimmunity and allergic dysregulation syndrome” (XLAAD) or “Immunodysregulation, polyendocrinopathy and enteropathy, X-linked syndrome” (IPEX). These individuals fail to develop CD4+CD25+ T cells and experience varied symptoms from insulin-dependent diabetes to anemia, as well as massive T cell infiltration of the skin and gastrointestinal tract.

The present invention features methods of identifying immune response modulators by measuring various aspects of FOXP3 function. 

• An approach to identify novel inhibitors for diseases that regulatory T cells are involved.
• Specific to FOXP3 functions that are relevant to the binding to HDAC and HAT.