Screening assays and methods of using same for screening to identify modulator agents or compounds that affect Th17 cell specification are described herein. Pharmaceutical compositions comprising agents or compounds that modulate Th17 cell specification are also encompassed. Methods for modulating Th17 cell specification using agents identified using assays described herein in pharmaceutical compositions are also envisioned. Such pharmaceutical compositions are useful for treating inflammatory conditions and autoimmune diseases associated with Th17 cell mediated pathology.