Clone 12D11 has been reported to be a mouse monoclonal antibody specific to the human gene, MAPK3, or Mitogen-activated protein kinase 3. Other suppliers describe clone 12D11 to be a mouse monoclonal antibody against human C4A, or complement C4A (Rodgers blood group). Indicated applications for antibody clone 12D11 include Western blot, immunohistochemistry, immunofluorescence, and ELISA.