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Prime-boost vaccine regimen confers protective immunity to human-derived enterotoxigenic Escherichia coli.
Lasaro, M O; Luiz, W B; Sbrogio-Almeida, M E; Ferreira, L C S.
Afiliação
  • Lasaro MO; Microbiology Department, Biomedical Science Institute, University of São Paulo, Av Prof. Lineu Prestes 1374, São Paulo 05508-000, Brazil.
Vaccine ; 23(19): 2430-8, 2005 Mar 31.
Article em En | MEDLINE | ID: mdl-15752829
Development of effective vaccines against diarrhea caused by enterotoxigenic Escherichia coli (ETEC) strains is still a priority for those living at or traveling to endemic regions. In this work, we evaluated the protective role of an anti-ETEC vaccine regimen based on parenteral priming with a DNA vaccine, pRECFA, followed by oral boosting with a recombinant attenuated Salmonella Typhimurium vaccine strain, HG3, both encoding the same antigen, the structural subunit (CfaB) of the ETEC CFA/I fimbriae. The DNA-priming Salmonella-boosting protocol enhanced both murine anti-CfaB serum IgG and fecal IgA antibody responses and increased the ability of serum antibodies to inhibit the adhesive properties of the CFA/I fimbriae expressed by live bacteria, as compared to mice immunized with only one vaccine type. Addition of a mucosal adjuvant (LTR192G) to the Salmonella vaccine strain further enhanced the synergic effects of the vaccine regimen on the induced CfaB-specific antibody responses. DBA/2 dams submitted to the prime-boost regimen transferred complete passive protection to suckling neonates challenged with a virulent ETEC strain. Detection of milk anti-CfaB IgA antibodies and protection conferred by vaccinated dams to neonates born from non-vaccinated dams indicated that secretion of antigen-specific IgA is the immune response induced by the protective vaccine regimen. These results demonstrate that priming with a DNA vaccine and boosting with a Salmonella strain enhances both quantitatively and qualitatively the antibody responses to the CfaB antigen and represents an alternative for either active or passive immunization approach to ETEC-associated diarrhea.
Assuntos
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Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Imunização Secundária / Vacinas de DNA / Vacinas contra Escherichia coli / Disenteria / Infecções por Escherichia coli Tipo de estudo: Prognostic_studies Limite: Animals / Female / Humans Idioma: En Revista: Vaccine Ano de publicação: 2005 Tipo de documento: Article País de afiliação: Brasil
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Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Imunização Secundária / Vacinas de DNA / Vacinas contra Escherichia coli / Disenteria / Infecções por Escherichia coli Tipo de estudo: Prognostic_studies Limite: Animals / Female / Humans Idioma: En Revista: Vaccine Ano de publicação: 2005 Tipo de documento: Article País de afiliação: Brasil