Used in vaccine development and diagnostic assays to study immune response against the Omicron variant of SARS-CoV-2. Serves as a key antigen for generating neutralizing antibodies in research settings. Employed in binding studies to evaluate the effectiveness of therapeutic antibodies and small-molecule inhibitors targeting the spike protein. Facilitates receptor interaction studies, particularly with ACE2, to understand viral entry mechanisms and mutations' impact on infectivity. Commonly used in ELISA, Western blot, and surface plasmon resonance (SPR) due to the Flag and His tags for detection and purification. Supports surveillance and characterization of emerging variants by providing a standardized reagent for comparative analysis.