Used in immunological research to quantify FOXP3 protein levels in biological samples, this ELISA kit helps study regulatory T cells (Tregs) involved in immune tolerance and suppression of excessive immune responses. It is widely applied in research on autoimmune diseases, cancer immunology, and transplant rejection, where understanding Treg activity is critical. The assay enables researchers to assess FOXP3 expression as a marker for Treg presence and function in cell cultures, tissue lysates, and serum samples. It supports drug development and mechanistic studies in immunotherapy by providing a reliable and sensitive method to monitor immune modulation.