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[Lipopolysaccharide changes in smooth-type avirulent Shigella in comparison with initial virulent strains]
Zhurnal Mikrobiologii, Epidemiologii I Immunobiologii
|February 1, 1992
Summary
Researchers compared lipopolysaccharides (LPS) from virulent and avirulent Shigella sonnei strains. Avirulent strains showed longer O-chains, potentially reducing immunogenicity and complement fixation, impacting antibody production.
Area of Science:
- Microbiology
- Immunology
- Molecular Biology
Background:
- Shigella sonnei lipopolysaccharides (LPS) are key virulence factors.
- Understanding structural differences between virulent and avirulent LPS is crucial for vaccine development.
Purpose of the Study:
- To comparatively analyze the lipopolysaccharides (LPS) of virulent and avirulent Shigella sonnei phase I strains.
- To investigate the structural basis for altered immunogenicity in avirulent S. sonnei variants.
Main Methods:
- Electrophoresis and densitometry of LPS preparations.
- Immunization of mice and assessment of antibody-producing cells using Jerne's test with sheep red blood cells (SRBC).
Main Results:
- Two of three avirulent S. sonnei LPS preparations exhibited increased long O-chains with repeating elements.
- Mice immunized with these LPS showed reduced antibody-producing cells compared to virulent LPS.
- A third avirulent strain, altered by transposon integration, displayed fine structural differences and a 3-4 fold decrease in immunogenicity.
Conclusions:
- Longer O-specific chains in LPS may inhibit complement fixation, potentially reducing immunogenicity.
- Structural variations in LPS, particularly O-chain length, significantly influence the immune response to S. sonnei.
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