Used in research and diagnostic applications to detect and neutralize the spike protein's receptor-binding domain (RBD) of SARS-CoV-2. Helps in studying virus entry mechanisms and evaluating immune responses in infected or vaccinated individuals. Employed in immunoassays such as ELISA, Western blot, and immunofluorescence to quantify RBD expression and assess antibody efficacy. Also utilized in therapeutic development to identify potential neutralizing agents against COVID-19 variants.