Used in vaccine development and diagnostic assays to detect neutralizing antibodies against the Omicron BA.2.75 variant of SARS-CoV-2. The His-tagged spike RBD protein serves as a key antigen in immunoassays, enabling measurement of immune response in infected or vaccinated individuals. It is also employed in therapeutic research, including monoclonal antibody screening and characterization, to evaluate binding affinity and inhibition efficacy. Its high purity and proper conformation support structural studies and epitope mapping for next-generation vaccine design.