Used in research and diagnostic applications to detect the spike protein's receptor-binding domain (RBD) of SARS-CoV-2. Helps in studying virus neutralization mechanisms and evaluating immune responses in infected or vaccinated individuals. Employed in immunoassays such as ELISA, Western blot, and immunofluorescence to quantify antibody binding and assess therapeutic efficacy. Supports development of diagnostic kits and potential therapeutics targeting viral entry into host cells.