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Immunological properties of the cell envelope components of Vibrio cholerae
Abstract:
Several immunobiological properties of cell envelope components of Vibrio cholerae such as mitogenicity, antigenicity, adjuvanticity and toxicity were tested in mice. Killed whole bacteria, spheroplasts, lipopolysaccharide and outer membrane proteins possessed mitogenic activity as determined by [3H]thymidine uptake in spleen cell cultures. All these components predominantly stimulated murine bone-marrow derived (B) lymphocytes. The mitogenicity induced by V. cholerae lipopolysaccharide was similar in magnitude to that observed with Salmonella typhimurium lipopolysaccharide. Vibrio cholerae lipopolysaccharide was mitogenic for gut-associated lymphocytes such as those obtained from Peyer's patches and small intestine. Antibody formation at the cellular level was detected by the haemolytic plaque assay. Plaque-forming cells to V. cholerae lipopolysaccharide were only detected when mice were immunized intraperitoneally with intact cells or with spheroplasts. Among the various cell envelope components, lipopolysaccharide alone possessed adjuvant properties as it increased the number of plaque-forming cells to sheep erythrocytes fourfold in mouse spleens. Also, lipopolysaccharide was the only component found to be toxic for the mouse (LD50 0 . 5 mg). Neither spheroplasts nor outer membrane of V. cholerae showed adjuvanticity or toxicity in mice.
Insights
The cell envelope components of Vibrio cholerae, particularly lipopolysaccharide, exhibit significant mitogenic and adjuvant properties in mice. Lipopolysaccharide is also the sole toxic component, highlighting its crucial role in cholera
Area of Science:
- Immunology
- Microbiology
Background:
- Cell envelope components of Vibrio cholerae possess various immunobiological properties.
- Understanding these properties is crucial for developing effective cholera vaccines and therapies.
Purpose of the Study:
- To investigate the immunobiological properties, including mitogenicity, antigenicity, adjuvanticity, and toxicity, of Vibrio cholerae cell envelope components in mice.
- To determine the specific roles of lipopolysaccharide, outer membrane proteins, and other components in immune stimulation.
Main Methods:
- Testing immunobiological properties in mice using spleen cell cultures and [3H]thymidine uptake assays.
- Assessing antibody formation via hemolytic plaque assay.
- Evaluating toxicity using LD50 determination.
Main Results:
- Killed whole bacteria, spheroplasts, lipopolysaccharide, and outer membrane proteins demonstrated mitogenic activity, primarily stimulating murine B lymphocytes.
- Vibrio cholerae lipopolysaccharide showed mitogenicity comparable to Salmonella typhimurium lipopolysaccharide and also stimulated gut-associated lymphocytes.
- Lipopolysaccharide was the only component exhibiting adjuvant properties, increasing antibody formation to sheep erythrocytes fourfold.
- Lipopolysaccharide was the sole toxic component, with an LD50 of 0.5 mg, while spheroplasts and outer membrane lacked adjuvanticity and toxicity.
Conclusions:
- Vibrio cholerae lipopolysaccharide is a potent mitogen and adjuvant, and the only toxic component among the tested cell envelope fractions.
- These findings underscore the critical immunomodulatory roles of Vibrio cholerae lipopolysaccharide in the host immune response.