RESUMO
Licensed as well as candidate cholera vaccines available at the present requires the dose preparation (included buffer) at the moment of application. The aim of this work was to evaluate the presentation in oral tablets of an inactivated cholera vaccine to avoid that inconveniences during application. We have therefore compared inactivated cultures of Vibrio cholerae with tablets formulation vaccine. We obtained that antigenic activity (ELISA) and immunogenicity in animal model (ELISA and vibriocidal tests) of V. cholerae inactivated cell remained unaltered in the final tablet formulation. The results suggest that the oral tablet formulation could be a useful pharmaceutical form in order to produce a new and affordable cholera vaccine.
Assuntos
Vacinas contra Cólera/administração & dosagem , Cólera/prevenção & controle , Administração Oral , Animais , Anticorpos Antibacterianos/sangue , Vacinas contra Cólera/imunologia , Contagem de Colônia Microbiana , Ensaio de Imunoadsorção Enzimática , Modelos Animais , Coelhos , Comprimidos , Vacinas de Produtos Inativados/administração & dosagem , Vacinas de Produtos Inativados/imunologia , Vibrio cholerae/imunologiaRESUMO
Genetically modified Vibrio cholerae strain 638 (biotype El Tor, serotype Ogawa) has previously been shown to be immunogenic in animal models and in human trials. Our objective in the work reported herein was to describe the process development methods for the production of the 638 attenuated cholera vaccine. Cell seed bank, culture of biomass, lyophilization and final formulation were processes were developed. The results show kinetics of culture that fulfils a logistical model. The microbiological properties, colonizing capability, immunogenicity and non-toxigenicity of the final product were indistinguishable from the properties of the working seed lot. We conclude that the non-reactogenic, immunogenic and protective strain 638 is robust and can withstand the fermentation processes required for large-scale production of a vaccine.
Assuntos
Vacinas contra Cólera , Tecnologia Farmacêutica , Vibrio cholerae/imunologia , Animais , Cólera/prevenção & controle , Toxina da Cólera/análise , Vacinas contra Cólera/efeitos adversos , Vacinas contra Cólera/imunologia , Indústria Farmacêutica , Fermentação , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Modelos Animais , Vacinas Atenuadas/efeitos adversos , Vacinas Atenuadas/imunologia , Vibrio cholerae/genética , Vibrio cholerae/patogenicidade , Vibrio cholerae/fisiologiaRESUMO
In recent clinical assays, our cholera vaccine candidate strain, Vibrio cholerae 638 El Tor Ogawa, was well tolerated and immunogenic in Cuban volunteers. In this work we describe the construction of 638T, a thymidine auxotrophic version of improved environmental biosafety. In so doing, the thyA gene from V. cholerae was cloned, sequenced, mutated in vitro, and used to replace the wild-type allele. Except for its dependence on thymidine for growth in minimal medium, 638T is essentially indistinguishable from 638 in the rate of growth and morphology in complete medium. The two strains showed equivalent phenotypes with regard to motility, expression of the celA marker, colonization capacity in the infant mouse cholera model, and immunogenicity in the adult rabbit cholera model. However, the ability of this new strain to survive environmental starvation was limited with respect to that of 638. Taken together, these results suggest that this live, attenuated, but nonproliferative strain is a new, promising cholera vaccine candidate.
Assuntos
Vacinas contra Cólera/imunologia , Timidilato Sintase/genética , Vibrio cholerae/imunologia , Sequência de Aminoácidos , Animais , Sequência de Bases , Clonagem Molecular , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Coelhos , Vacinas Atenuadas/imunologia , Vibrio cholerae/crescimento & desenvolvimentoRESUMO
Vibrio cholerae 638 (El Tor, Ogawa), a new CTXPhi-negative hemagglutinin/protease-defective strain that is a cholera vaccine candidate, was examined for safety and immunogenicity in healthy adult volunteers. In a double-blind placebo-controlled study, no significant adverse reactions were observed in volunteers ingesting strain 638. Four volunteers of 42 who ingested strain 638 and 1 of 14 who received placebo experienced loose stools. The strain strongly colonized the human small bowel, as evidenced by its isolation from the stools of 37 of 42 volunteers. V. cholerae 638, at doses ranging from 4 x 10(7) to 2 x 10(9) vibrios, elicited significant serum vibriocidal antibody and anti-Ogawa immunoglobulin A antibody secreting cell responses.