Used in research and diagnostic applications to study autoimmune diseases such as pemphigus vulgaris, where DSG3 (Desmoglein 3) is a primary autoantigen. The His tag allows for easy purification and detection, making it suitable for immunoassays, antibody binding studies, and development of diagnostic kits. It is also employed in epitope mapping and therapeutic antibody screening to evaluate specificity and affinity of anti-DSG3 antibodies.