Immunogen sequence: NKKKLFMIYG KWTECLWGID PVSYESFKKQ ERRGDHLRKA KLDEDSGKAD SDVADDVPVA QETVQVIPGS KLLWRINTRP PNSAQMYNFT SFTVSLNELE TGMEKTLPPT DCRLRPDIRG MENGNMDLAS QEKERLEEKQ REARRERAKE EAEWQTRWFY PGNNPYTGTP DWLYAGDYFE RNFSDCPDIY; Positive Samples: U-251M