Related Experiment Video
Updated: Jul 19, 2026

Purification and Visualization of Lipopolysaccharide from Gram-negative Bacteria by Hot Aqueous-phenol Extraction
Published on: May 28, 2012
The love-hate relationship between bacterial polysaccharides and the host immune system
Sarkis K Mazmanian1, Dennis L Kasper
1Division of Biology, California Institute of Technology, Mail code 156-29, 1200 East California Boulevard, Pasadena, California 91125, USA.
Gut bacteria significantly influence the mammalian immune system. Commensal bacteria produce molecules that promote CD4(+) T-cell expansion, enhancing host health and potentially explaining the hygiene hypothesis for allergies.
Area of Science:
- Immunology
- Microbiology
- Gastroenterology
Background:
- The human gut hosts a vast ecosystem of 10^13-10^14 bacteria.
- The interplay between gut microbiota and the host immune system is crucial for health.
Purpose of the Study:
- To explore the relationship between the mammalian immune system and gut bacteria.
- To review evidence on how commensal bacteria modulate immune responses.
Main Methods:
- Review of existing scientific literature.
- Analysis of immunomodulatory molecules produced by gut commensals.
Main Results:
- Commensal bacteria produce molecules that beneficially influence immune responses.
- These molecules elicit the clonal expansion of CD4(+) T-cell populations.
- This process contributes to host health and disease protection.
Conclusions:
- Gut bacteria play a vital role in immune system development and regulation.
- Bacterial modulation of CD4(+) T-cells offers protection against diseases.
- Findings support the 'hygiene hypothesis' regarding allergic disorders at a molecular level.
More Related Videos
08:24Injections of Lipopolysaccharide into Mice to Mimic Entrance of Microbial-derived Products After Intestinal Barrier Breach
Published on: May 2, 2018
13:47Opsono-Adherence Assay to Evaluate Functional Antibodies in Vaccine Development Against Bacillus anthracis and Other Encapsulated Pathogens
Published on: May 19, 2020
Related Concept Videos
Defense Against Bacterial Pathogens
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...
Formation of Lipopolysaccharides
Colonisation of Pathogens
Glycocalyx and its Functions
Components of...
Antigens Involved in Adaptive Immunity
Complete Antigens
Complete antigens possess both immunogenicity and reactivity.
Determinants of Bacterial Pathogenicity and Virulence