Immunogen sequence: RCSDAPPRAS ALPAPPTGSA LPDPQTASAL PDPPAASALP AALAVISFLL GLGLGVACVL ARTQIKKLCS WRDKNSAACV VYEDMSHSRC NTLSSPNQYQ. CD7, also known as gp40 or Leu9, is a 40 kDa receptor and member of the immunoglobulin gene superfamily. It features an N-t