Immunogen sequence: TISQRPYRDR VIHLLALKAY KKPELLARLQ KDGVNQKDKN SLGAILQQVA NLNSKDLSYT LKDYVFKELQ RDWPGYSEID RRSLESVLSR KLN. SHP-1 (PTPN6) is a non-receptor protein tyrosine phosphatase that is expressed primarily in hematopoietic cells. The enzyme is com