Anti-CD73 antibodies detect the protein encoded by the human gene, NT5E, also known as 5'-nucleotidase ecto. The full-length protein is 63,368 daltons in mass with 2 identified isoforms and is reported to contain sites of glycosylation. The CD73 antigen is a documented mesenchymal stem cell marker. Anti-CD73 antibodies detect the protein encoded by the human gene, NT5E, also known as 5'-nucleotidase ecto. The full-length protein is 63,368 daltons in mass with 2 identified isoforms and is reported to contain sites of glycosylation. The CD73 antigen is a documented mesenchymal stem cell marker.