Nanocochleates containing N-Octylglicoside extracted Vibrio cholerae antigens elicited high vibriocidal antibodies titers after intragastric immunization in a mice model.

Biological detergents are used in research laboratories, to extract or solubilize proteins from cell membranes. In order to evaluate the ability to extract antigens from the bacterial cell surface of the wild Vibrio cholerae strain C7258 and study their immunogenic potential by forming proteoliposomes and cochleate and preserving their immunogenicity, the non-ionic detergent, n-Octylglucoside (n-OG), and the Zwitterionic detergent (3-cholamidopropyl dimethylammonio 1-propanesulfonate; CHAPS) were tested in concentrations between 5 and 15%. The anionic detergent sodium deoxycholate (DOC) was used as a reference. Electrophoretic, immunochemical and electron microscopy techniques have characterized the extracts and their chromatographic fractions. With CHAPS and n-OG detergents in concentrations between 5 and 15%, a higher yield was obtained in the extraction of proteins and lipopolysaccharides (LPS) and other components from the bacterial surface compared to 10% DOC. When using 10% DOC, 15% CHAPS and n-OG between 5 and 15%, stable proteoliposomes were formed, of average size between 82 and 93 nm in diameter, with known proportions of proteins, LPS and other components. In some of the concentrations, liposomes were formed with almost pure proteins. Some cholera outer membrane proteins like the 17 kDa protein, which corresponds to the mannose-sensitive hemagglutinin (MSHA), which mediates the adhesion to the brush border of the small intestine and the outer membrane protein U (OMPU) were identified with monoclonal antibodies (mAbs) and purified. The fundamental components of liposomes, proteins and LPS, retained their molecular weights, when compared with known standards and by processing programs of electrophoretic profiles and their antigenicity, without alterations due to the extraction procedure, as could be verified by immune identification techniques with monoclonal antibodies in the case of LPS, significant antigens in this pathogen. The main purpose of the present work was to show that a new anticholera vaccine formulation based on cochleates, containing selected protein and LPS fraction extracted by detergents, is able to elicit protective high titers of bactericidal antibodies after intragastric immunization in the mice model. The objective was achieved.

Enhancement of the immune response to poorly immunogenic gangliosides after incorporation into very small size proteoliposomes (VSSP).

Certain gangliosides are tumor-associated antigens that constitute potential targets for cancer immunotherapy. A major drawback in the design of ganglioside-based cancer vaccines, however, is the poor immunogenicity of these glycolipids. Here we report the immunological and physicochemical properties of very small size proteoliposomes (VSSP) obtained by using anionic detergents to incorporate gangliosides into the outer membrane protein complex (OMPC) of N. meningitidis. VSSP of three different gangliosides, GM3, NGcGM3 and GD3, were tested. These gangliosides differ in level of expression in normal tissues and in immunogenicity in different animal species. We show that the immunization with VSSP in an oil adjuvant consistently induced both IgM and IgG anti-ganglioside antibodies. In the mouse, the anti-ganglioside IgG fraction was not restricted to the typical T-independent isotype IgG3. Unexpectedly, significant levels of the T-dependent IgG1, IgG2a and particularly IgG2b were also found. VSSP-mediated enhancement of the immunogenicity was not restricted to the relatively immunogenic ganglioside GD3, satisfactory immune responses against highly tolerated GM3 and NGcGM3 were also obtained. Similar results were achieved in chickens and monkeys. No reactogenicity was observed even when self-gangliosides were used for immunization. VSSP overcame natural tolerance to gangliosides in an adjuvant dependent fashion.

Vaccine against group B Neisseria meningitidis: protection trial and mass vaccination results in Cuba.

The Cuban vaccine, first in the world with proven efficacy against group B-caused disease, is based on outer membrane proteins from B meningococci capable of inducing long-lasting and high-titered bactericidal antibodies in humans. This bactericidal activity has a wide spectrum against all pathogenic group B Neisseria meningitidis tested. A randomized, double-blind controlled trial of the vaccine efficacy was performed during 1987-1989 with 106,000 10-14 years old students from 197 boarding schools in seven provinces. The efficacy obtained was 83% (chi 2, p less than 0.002; Fischer exact, p less than 0.001). In a second field trial including 133,600 persons from 5 months to 24 years of age in Ciego de Avila province (30 cases/10(5) inhabitants, the highest incidence rate in Cuba) by comparing vaccinated and non-vaccinated population after 2.5 years of observation and careful follow-up, the efficacy and safety was confirmed. Because of these results and because of the very low reactogenicity of the vaccine, the Ministry of Public Health took the advice of the Scientific Council to vaccinate all children between 3 months and 6 years of age in the most affected provinces. No severe or long lasting reactions to the vaccine were observed after the millions of doses administered. The efficacy of vaccination varied in the provinces between 83% and 94%, among age groups ranging from 3 months and 20 years. After 3 years of massive application no severe reactions occurred and one of the most severe epidemics has been practically eradicated.