Study: NCT01739231

Intervention type: BIOLOGICAL
Group type: EXPERIMENTAL
Intervention: ACE527
Description: 3x10\^9 cfu ACE527 vaccine strain. Comprised of three genetically attenuated and engineered strains of E. coli, with antigen profiles covering a wide range of ETEC surface colonization factor antigens (CFA/I, CFA/II \[CS1, CS2, CS3\] and CFA/IV \[CS5, CS6\]) and also expressing LTB, the inactive subunit of LT (ETEC heat labile toxin). The constituent strains of ACE527 were:~* ACAM2025: a live, attenuated, CFA/I, LTB positive strain~* ACAM2022: a live, attenuated, CS5, CS6, LTB positive strain, and~* ACAM2027: a live, attenuated, CS1, CS2, CS3, LTB positive strain.

Intervention type: BIOLOGICAL
Group type: EXPERIMENTAL
Intervention: ACE527
Description: 3x10\^9 cfu ACE527 vaccine strain. Comprised of three genetically attenuated and engineered strains of E. coli, with antigen profiles covering a wide range of ETEC surface colonization factor antigens (CFA/I, CFA/II \[CS1, CS2, CS3\] and CFA/IV \[CS5, CS6\]) and also expressing LTB, the inactive subunit of LT (ETEC heat labile toxin). The constituent strains of ACE527 were:~* ACAM2025: a live, attenuated, CFA/I, LTB positive strain~* ACAM2022: a live, attenuated, CS5, CS6, LTB positive strain, and~* ACAM2027: a live, attenuated, CS1, CS2, CS3, LTB positive strain.

Intervention type: BIOLOGICAL
Group type: EXPERIMENTAL
Intervention: dmLT
Description: A derivative of wild-type enterotoxigenic Escherichia coli heat-labile enterotoxin that has been genetically modified by replacing the arginine at amino acid position 192 with glycine and the leucine at amino acid position 211 with alanine (13). These two amino acid substitutions take place in proteolytic cleavage sites which are critical for activation of the secreted toxin molecules.

Intervention type: BIOLOGICAL
Group type: ACTIVE_COMPARATOR
Intervention: CeraVacx placebo
Description: CeraVacx® is used to neutralize gastric acidity upon ingestion of vaccine. It was also used as the placebo in this study. CeraVacx® was prepared from the commercial product (Cera Products, Inc.); 9.5 grams were added to sterile water for each dose and mixed. Each dose contained 7 grams of rice syrup, 2 grams of sodium bicarbonate, and 0.5 grams of trisodium citrate.

Intervention type: BIOLOGICAL
Group type: EXPERIMENTAL
Intervention: H10407 challenge strain
Description: Approximately 2 x 10\^7 cfu of the fully virulent ETEC strain. Previously administered to 91 volunteers at this challenge dose by the CIR clinical team over the previous 4 years in conjunction with other Phase 1/2b trials.

Intervention type: BIOLOGICAL
Group type: EXPERIMENTAL
Intervention: H10407 challenge strain
Description: Approximately 2 x 10\^7 cfu of the fully virulent ETEC strain. Previously administered to 91 volunteers at this challenge dose by the CIR clinical team over the previous 4 years in conjunction with other Phase 1/2b trials.

Intervention type: BIOLOGICAL
Group type: ACTIVE_COMPARATOR
Intervention: H10407 challenge strain
Description: Approximately 2 x 10\^7 cfu of the fully virulent ETEC strain. Previously administered to 91 volunteers at this challenge dose by the CIR clinical team over the previous 4 years in conjunction with other Phase 1/2b trials.

Intervention type: BIOLOGICAL
Group type: ACTIVE_COMPARATOR
Intervention: H10407 challenge strain
Description: Approximately 2 x 10\^7 cfu of the fully virulent ETEC strain. Previously administered to 91 volunteers at this challenge dose by the CIR clinical team over the previous 4 years in conjunction with other Phase 1/2b trials.