Immunogen was recombinant human Angiotensin-converting Enzyme 2 (ACE2) with C-terminal His-tag, derived from the transfected human HEK293 cells. This antibody was produced from a hybridoma resulting from the fusion of a mouse myeloma with B cells obtained from a mouse immunized with the immunogen. The IgG fraction of tissue culture supernatant was purified by Protein G/A affinity chromatography.