Used in immunological research to study T-cell activation and differentiation, particularly in the development of Th1 immune responses. Serves as a tool in assays evaluating cytokine signaling pathways and immune regulation. The Fc tag enables easy detection and purification, and facilitates prolonged half-life in vitro and in vivo, making it suitable for therapeutic development and preclinical studies in autoimmune diseases, cancer immunotherapy, and vaccine adjuvants.