Abstract
In the present study the role of Yersinia enterocolitica antigens in humoral immunity against secondary Y. enterocolitica infection has been investigated. For this purpose, BALB/c mice, 4 weeks after immunization by primary infection with a sublethal dose of various Y. enterocolitica strains and mutant strains, were challenged with a lethal dose of highly virulent Y. enterocolitica strains of serotype O:8. As evident from the survival rate and protection against bacterial growth in the spleens of mice, only immunization with wild-type or attenuated strains harbouring an intact virulence plasmid mediated protection against a lethal challenge. Protection by immunization with plasmid-harbouring strains correlated with persistence of the bacteria in spleens for at least 7 days after immunization and high serum titres of Yersinia-specific antibodies directed against both chromosomal and plasmid-encoded determinants. Furthermore, the adoptive transfer of the purified IgG fraction of a rabbit serum specific for the adhesin YadA encoded by virulence plasmid pO8 from Y. enterocolitica O:8 mediated protection against a lethal challenge with the serotype O:8 strain harbouring the virulence plasmid pO8 but did not mediate protection when this strain harboured the virulence plasmid pO9 from serotype O:9. In summary, the results demonstrate that in our experimental mouse infection model: (i) the presence of the intact virulence plasmid in an immunizing Y. enterocolitica strain is essential for induction of protection against a lethal challenge with highly virulent Y. enterocolitica and (ii) that antibodies against plasmid-encoded determinants of Y. enterocolitica, especially YadA, are of major importance for achievement of protective immunity in mice.
- 50,
- active,
- animals,
- antibodies,
- antibody
- antigens,
- bacterial,
- c,
- dose
- enterocolitica,
- female,
- formation,
- g,
- immunity,
- immunization,
- immunoglobulin
- inbred
- infections
- lethal
- mice,
- passive,
- specificity,
- spleen,
- virulence,
- yersinia
- {balb}
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