E. coli double mutant heat-labile toxin

The E. coli double mutant heat-labile toxin (dmLT), also known as LT(R192G/L211A), is a genetically modified form of the native Escherichia coli heat-labile enterotoxin (LT). It contains two point mutations (R192G and L211A) that significantly reduce its enterotoxicity while retaining strong mucosal adjuvant properties. The AB5 multimeric structure consists of one enzymatically active A subunit and five B subunits responsible for cell binding. The A subunit catalyzes ADP-ribosylation of Gs protein alpha-subunits, leading to increased cAMP in target cells; however, the introduced mutations greatly diminish this activity in dmLT compared to wild-type LT[1][2][3][5]. As a mucosal adjuvant, dmLT enhances immune responses—particularly IL-17A production by T cells—when co-administered with various antigens via oral or sublingual routes[1][2]. It has been evaluated preclinically and in early-phase clinical trials as an adjuvant for vaccines against pathogens such as Helicobacter pylori, Streptococcus pneumoniae, Mycobacterium tuberculosis (PPD antigen), and enterotoxigenic E. coli itself[1][2][6].

Other names

double mutant heat-labile enterotoxinEscherichia coli double mutant heat-labile toxinLTR192G/L211A