Table 1.
Overview of the ETEC vaccine development landscape.
| Type of Vaccine | Candidate | Description of ETEC Candidate | Developmental stage | Developer |
|---|---|---|---|---|
| Inactivated whole cell vaccine | ETEC cells with LT components ETVAX | Recombinant E. coli (one E. coli K12 and three O78 positive E. coli) strains that over-express CFA/I, CS3, CS5 and CS6 antigens combined with hybrid LT/CTB, adjuvanted with dmLT | Phase 2b | Scandinavian Biopharma |
| Live attenuated Shigella-vectored | ShigETEC toxin hybrid | ShigETEC LPS-free cell expressing conserved ETEC and Shigella antigens | Phase 1 | EveliQure |
| Shigella hybrid (1208S-122) | Attenuated Shigella vaccine strains engineered to express ETEC CF and LT | Phase 1 | University of Maryland’s Center for Vaccine Development (CVD) | |
| Subunit | Fimbrial tip adhesin (FTA) | Class 5 fimbriae combined with other CF/CS, designed to block adhesion of ETEC to the intestinal epithelium by inducing antibodies to the tips of fimbriae | Phase 1/2b | US Naval Medical Research Center (NMRC) |
| Multi-Epitope Fusion Antigen (MEFA) (MecVax) | On CFA/I backbone express CS1-CS6, consensus peptide fused to 3xST-dmLTA-1LTB dmLT-ST toxoid | Preclinical | University of Illinois; Johns Hopkins University | |
| Potential Subunits | Alternative or complementary to known virulence factors | YghJ, a protein secreted by the same pathway as ETEC LT; EatA, a serine protease that degrades mucin and promotes ETEC access to mucosal surfaces, EtpA, a secondary adhesin factor | Preclinical | Washington University, St Louis; CVD; University of Bergen; GlyProVac |
| ST | Multiple constructs designed to improve immunogenicity with no toxicity or autoreactivity | Preclinical | University of Bergen; Tulane University |
Definitions: CF/CS, colonization factor antigens; ETEC, enterotoxigenic Escherichia coli; LT, heat-labile toxin; ST, heat-stable toxin; dmLT, double-mutant heat-labile toxin (LTR192G/L211A).