Notes: Researchers used the pGEM®-T Vector System to clone the entire 1.4kb Shiga toxin type 2 gene (Stx2) from E. coli O157-H7 C600 (933W). The resultant construct, named pGEMTStx2, was used as a template in PCR to amplify each region of the gene corresponding to Shiga toxin type 2 subunits A and B. Each PCR product was digested with BamHI and EcoRI before ligation into pCDNA 3.1+ (Invitrogen) to create pStx2ΔA and pStx2B. Mice were then immunized with either one or both of these constructs and another construct expressing murine granulocyte-macrophage colony-stimulating factor. Expression of each subunit in mouse tissue was verified by RT-PCR with specific primers and the AccessQuick™ RT-PCR System. (2701)