Used in immunological research to study antibody-dependent cellular cytotoxicity (ADCC) and phagocytosis. Binds to the Fc region of IgG antibodies, enabling analysis of immune cell activation and therapeutic antibody efficacy. Commonly employed in binding assays, protein-protein interaction studies, and screening of monoclonal antibodies for improved Fc receptor engagement. The His tag facilitates easy purification and detection in recombinant expression systems.