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Cell wall structures which may be important for successful immunization with Salmonella-Shigella hybrid vaccines

C L Schultz1, B Kaufman, D Hamilton

  • 1Department of Biologics Research, Walter Reed Army Institute of Research, Washington, D.C. 20307-5100.

Vaccine
|April 1, 1990
PubMed

Insights

Efficacy of the S. typhi/S. sonnei hybrid (Ty/Shig) live oral vaccine strain 5076-1C varied between lots. Protected lots had observable flagella and pili, suggesting these surface structures are crucial for immune response.

Area of Science:

  • Microbiology
  • Vaccinology
  • Immunology

Background:

  • Shigellosis remains a significant global health concern, necessitating effective vaccines.
  • The development of live oral vaccines, such as the S. typhi/S. sonnei hybrid (Ty/Shig) strain 5076-1C, offers a promising approach to combatting Shigella infections.

Purpose of the Study:

  • To evaluate the efficacy of different lots of the Ty/Shig live oral vaccine strain 5076-1C in human volunteers.
  • To identify potential correlates of protection for the Ty/Shig vaccine.

Main Methods:

  • Human volunteers were challenged with virulent S. sonnei after vaccination with three separate lots of the Ty/Shig vaccine.
  • Vaccine lots were analyzed using immunological tests and electron microscopy to assess bacterial surface structures.

Main Results:

  • Two vaccine lots (2 and 5) demonstrated protective efficacy against S. sonnei challenge, while one lot (8) did not.
  • Protected vaccine lots (2 and 5) exhibited reactivity with anti-flagellar serum and possessed observable flagella and pili.
  • The non-protective lot (8) lacked observable pili and did not react with anti-flagellar serum.

Conclusions:

  • The presence of flagella and pili on the Ty/Shig hybrid vaccine strain appears critical for inducing a protective immune response.
  • Surface structures of the Ty/Shig vaccine are important factors influencing its efficacy.

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