ACE2 and infection: We chose to create two different proteins: Dx-SARS2-noRBD for an immune response against SARS-CoV-2 as an indication of an infection and Dx-SARS2-RBD for the RBD on the spike protein, which is highly immunogenic, and antibodies that bind to this domain can be neutralized by blocking the interaction between the virus and its host cell entry receptor, ACE-2 [49,50].