Clone KT3 has been reported to be a monoclonal antibody specific to the human gene, COL18A1, or Collagen type XVIII alpha 1 chain. Other suppliers describe clone KT3 to be a monoclonal antibody against mouse CD3E, or CD3 antigen, epsilon polypeptide. This antibody clone has been reported to also recognize the mouse ortholog of the target gene. Indicated applications for antibody clone KT3 include immunohistochemistry, flow cytometry, immunofluorescence, and ELISA.