Preparation and preclinical evaluation of a freeze-dried formulation of a novel combined multivalent whole-cell/B-subunit oral vaccine against enterotoxigenic Escherichia coli diarrhea
Journal article, 2016

A promising liquid killed multivalent whole-cell plus enterotoxin B-subunit oral vaccine against enterotoxigenic Escherichia coli (ETEC), the primary cause of diarrhea among children in low-income countries and travelers to these areas, has recently been developed and tested in preclinical and phase-I and phase-II clinical studies. The vaccine contains killed E. coli bacteria over-expressing the main ETEC colonization factors (CFs) CFA/I, CS3, CS and C6, and a recombinant enterotoxin B subunit protein (LCTBA) given together with a recently developed enterotoxin-derived adjuvant, dmLT. A dry-powder vaccine formulation should be advantageous especially for use in low-income countries. Here we describe a method to produce a dry-powder formulation by freeze-drying of the vaccine using inulin as stabilizer. Although not completely preventing aggregation of bacteria during freeze-drying, the stabilizer provided both improved overall bacterial morphology and almost complete recovery of the CF and B subunit antigens. Most importantly, oral-intragastric immunization of mice with the freeze-dried vaccine together with dmLT adjuvant elicited strong intestinal mucosal and serum antibody responses against all vaccine antigens, which were comparable to those achieved with the liquid vaccine. Our results indicate the feasibility to use freeze-drying with inulin as stabilizer for preparing a dry-powder formulation of the novel ETEC vaccine with retained oral-mucosal immunogenicity compared to the liquid formulation. (C) 2016 Elsevier B.V. All rights reserved.

Vaccine

Stabilizer

Inulin

Immunogenicity

ETEC

Freeze-dried

Author

Annika Borde

University of Gothenburg

Annelie Ekman

University of Gothenburg

Anette Larsson

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

Nils I A Carlin

Scandinavian Biopharma

Jan Holmgren

University of Gothenburg

Joshua Tobias

University of Gothenburg

European Journal of Pharmaceutics and Biopharmaceutics

0939-6411 (ISSN) 18733441 (eISSN)

Vol. 108 18-24

Driving Forces

Sustainable development

Subject Categories

Immunology in the medical area

Areas of Advance

Life Science Engineering (2010-2018)

DOI

10.1016/j.ejpb.2016.07.011

More information

Latest update

11/22/2019