Immunogen sequence: AIDAPKTCSP KQFACRDQIT CISKGWRCDG ERDCPDGSDE APEICPQSKA QRCQPNEHNC LGTELCVPMS RLCNGVQDCM DGSDEGPHCR ELQGNCSRLG CQHHCVPTLD GPTCYCNSSF QLQADGKTCK DFDECSVYGT CSQLCTNTD. CD91 is a 600 kDa type I transmembrane protein composed of an alpha a