Generation and characterization of a live attenuated enterotoxigenic Escherichia coli combination vaccine expressing six colonization factors and heat-labile toxin subunit B

Live attenuated oral enterotoxigenic Escherichia coli (ETEC) vaccines have been demonstrated to be safe and immunogenic in human volunteers and to provide a viable approach to provide protection against this important pathogen. This report describes the construction of new ETEC vaccine candidate strains from recent clinical isolates and their characterization. All known genes for ETEC toxins were removed, and attenuating deletion mutations were made in the aroC, ompC, and ompF chromosomal genes. An isolate expressing coli surface antigen 2 (CS2), CS3, heat-labile toxin (LT), heat-stable toxin (ST), and enteroaggregative Escherichia coli heat-stable toxin 1 (EAST1) was attenuated to generate ACAM2007. The subsequent insertion of the operon encoding CS1 created ACAM2017, and this was further modified by the addition of an expression cassette containing the eltB gene, encoding a pentamer of B subunits of LT (LTB), to generate ACAM2027. Another isolate expressing CS5, CS6, LT, ST, and EAST1 was attenuated to generate ACAM2006, from which a lysogenic prophage was deleted to create ACAM2012 and an LTB gene was introduced to form ACAM2022. Finally, a previously described vaccine strain, ACAM2010, had the eltB gene incorporated to generate ACAM2025. All recombinant genes were incorporated into the chromosomal sites of the attenuating mutations to ensure maximal genetic stability. The expression of the recombinant antigens and the changes in plasmids accompanying the deletion of toxin genes are described. Strains ACAM2025, ACAM2022, and ACAM2027 have been combined to create the ETEC vaccine formulation ACE527, which has recently successfully completed a randomized, double-blind, placebo-controlled phase I trial and is currently undergoing a randomized, double-blind placebo-controlled phase II challenge trial, both in healthy adult volunteers.

Medienart:

E-Artikel

Erscheinungsjahr:

2011

Erschienen:

2011

Enthalten in:

Zur Gesamtaufnahme - volume:18

Enthalten in:

Clinical and vaccine immunology : CVI - 18(2011), 12 vom: 15. Dez., Seite 2128-35

Sprache:

Englisch

Beteiligte Personen:

Turner, Arthur K [VerfasserIn]
Stephens, Jonathan C [VerfasserIn]
Beavis, Juliet C [VerfasserIn]
Greenwood, Judith [VerfasserIn]
Gewert, Cornelia [VerfasserIn]
Randall, Roger [VerfasserIn]
Freeman, Donna [VerfasserIn]
Darsley, Michael J [VerfasserIn]

Links:

Volltext

Themen:

Bacterial Toxins
Escherichia coli Vaccines
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Vaccines, Attenuated
Vaccines, Combined
Vaccines, Synthetic
Virulence Factors

Anmerkungen:

Date Completed 14.03.2012

Date Revised 20.10.2021

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1128/CVI.05345-11

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM212181734