| abstract |
An expression plasmid is disclosed which comprises a DNA sequence coding for subunit B of a heat-labile enterotoxin, and a promoter selected from the group consisting of λP L promoter, λP R promoter, trp promoter, tac promoter and T7 promoter, the DNA sequence being located at a position downstream from the promoter. An Escherichia coli transformant bearing such a plasmid and the expression of subunit B of a heat-labile enterotoxin are also disclosed. |