Abstract

A vaccine candidate against the enteric pathogen Vibrio cholerae was developed based on a proteoliposome (PL) formulation using a wild type strain C7258, V. Cholerae O1, El Tor Ogawa as part of strategy to develop a combined formulation against enteric diseases preventable by the stimulation of the mucosal immune system. A detergent extraction method was applied to obtain the PL. Scanning electron microscopy and molecular exclusion chromatography showed the presence of two PL populations. Photon correlation spectroscopy studies were then carried out to evaluate the size (169.27 +/- 3.85 nm), polydispersity (0.410) and zeta potential (-23.28 +/- 1.21 mV) of the PL. SDS-PAGE and Western blot analysis revealed the presence of lipopolysaccharide (LPS), mannose-sensitive haemagglutinin (MSHA) and a range of outer membrane proteins, including OmpU. BALB/c mice were immunized intranasally with two doses of PL containing 25 mu g of LPS each 28 days apart. The mice showed high anti-LPS IgG titres (3.36 +/- 0.235) and vibriocidal antibodies (3.70 +/- 0.23) after two weeks from last dose. These results show for the first time that PL can be obtained from V. cholerae O1 and when administer by intranasal route has the potential to protect against this pathogen. (C) 2008 Published by Elsevier Ltd.