6533b7ddfe1ef96bd1273de6
RESEARCH PRODUCT
Antiidiotypic DNA vaccination induces serum bactericidal activity and protection against group B meningococci
Concetta BeninatiMauro BorettiWalter MaglianiSalvatore PapasergiMilena ArigòStefania ContiGiuseppe MancusoGiuseppe TetiElisabetta GeraceCarmelo BiondoMaria Elsa GambuzzaLuciano PolonelliAngelina Midirisubject
Blood Bactericidal ActivityImmunologyImmunoglobulin Variable Regionchemical and pharmacologic phenomenaBlood Bactericidal ActivityNeisseria meningitidis Serogroup BEpitopeArticleMicrobiologyDNA vaccinationMiceAntigenserogroup B Neisseria meningitidis; single chain variable fragment; DNA vaccinationChlorocebus aethiopsVaccines DNAImmunology and AllergyAnimalsRats WistarMice Inbred BALB CbiologyImmunogenicityArticlesVirologyAntibodies BacterialRatsBacterial vaccineMeningococcal InfectionsImmunizationAnimals NewbornBacterial VaccinesCOS Cellsbiology.proteinAntibodydescription
No vaccine is available for preventing infections by serogroup B Neisseria meningitidis (MenB), which accounts for a major portion of meningococcal cases in developed countries, because of the poor immunogenicity of the capsular polysaccharide (CP) even after protein conjugation. We have previously induced anticapsular antibodies by immunization with a single chain variable fragment (scFv), which mimics a protective CP epitope. This surrogate antigen, however, was ineffective at inducing serum bactericidal activity, an accepted marker of protection in humans. Serum bactericidal activity was consistently achieved by immunizing mice with the scFv-encoding gene. Immunization with vectors without a secretory signal sequence before the scFv resulted in markedly higher bactericidal activity relative to those with such a sequence. The induced antibodies were capsule specific, as shown by complete inhibition of bactericidal activity by purified MenB CP and by resistance to killing of MenA or MenC. Moreover, these antibodies were predominantly of the IgG2a isotype, reflecting a T helper type 1 response. Administration of sera from scFv gene–vaccinated animals protected infant rats against MenB bacteremia. These data illustrate the potential of vaccination with genes encoding capsular mimics in providing protection against MenB and other encapsulated bacteria.
year | journal | country | edition | language |
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2006-01-05 |