FIG 4.
Illustration of the construction and detection of LT mutants e2m to e11m and LT with LTA1 epitope e2, e3, e4, e5, e6, e7, e8, e9, e10, or e11 substituted by the MBP epitope KDAQTNSSS. (A) LT mutant genetic structure and chimeric gene construction. Primers pBR/LT-F and pBR/LT-R were specific for the substitution of each LTA1 epitope with the MBP epitope. (B) Western blot with anti-LT antiserum to detect LTB subunit, mutated LTA subunit, and AB5 holotoxin-structured LT mutants. Lanes: (+), LT from recombinant LT strain 8460; (−), proteins from host strain E. coli DH5α. M, molecular marker, in kilodaltons.