Related Experiment Video
Updated: Jun 13, 2026
Investigating the Effects of Probiotics on Pneumococcal Colonization Using an In Vitro Adherence Assay
Published on: April 28, 2014
Evaluation of adhesion capacity, cell surface traits and immunomodulatory activity of presumptive probiotic
Charalambos Kotzamanidis1, Andreas Kourelis, Evanthia Litopoulou-Tzanetaki
1Department of Genetics, Development & Molecular Biology, Biology School, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece.
Insights
Certain Lactobacillus strains from infants and Feta cheese show potent immunostimulatory activity. These probiotics modulate gut immunity via Toll-like receptors, enhancing beneficial cytokine production without inflammation.
Area of Science:
- Microbiology
- Immunology
- Gastroenterology
Background:
- Lactobacilli are key gut microbes with potential probiotic properties.
- Characterizing their immunomodulatory effects is crucial for understanding gut health.
- Previous studies suggest cell surface traits correlate with probiotic activity.
Purpose of the Study:
- To genotype Lactobacillus strains using PFGE.
- To assess the immunostimulatory and immunomodulatory potential of selected Lactobacillus strains.
- To elucidate the molecular mechanisms underlying their interaction with the host immune system.
Main Methods:
- Pulse field gel electrophoresis (PFGE) for strain genotyping.
- In vitro assessment of cell surface traits (hydrophobicity, autoaggregation, adhesion).
- Mouse air pouch model to evaluate in vivo immune responses, including cytokine production and cell migration.
Main Results:
- Distinct PFGE patterns were observed, with two strains showing identical profiles.
- Strains DC421, DC429, and 2035 demonstrated significant immunostimulatory activity in the mouse air pouch model.
- These strains modulated gut-associated lymphoid tissue, inducing IgA and specific cytokine profiles (IFN-gamma, IL-5, IL-6, IL-10) via Toll-like receptor (TLR) signaling.
- Cell surface traits alone did not fully predict immunostimulatory capacity.
Conclusions:
- The mouse air pouch model effectively identifies potent probiotic Lactobacillus strains.
- Lactobacillus strains can exert immunomodulatory effects in the gut through TLR-mediated pathways.
- A complex interplay of factors, beyond surface traits, governs Lactobacillus-host immune interactions.
Abstract:
Twelve lactobacilli previously isolated from newborn infants' gastrointestinal tract and Feta cheese were further characterized by pulse field gel eletrophoresis (PFGE). All strains exhibited distinct PFGE genotypic patterns with the exception of DC421 and DC423 strains possessing identical patterns. The strains DC421, 2035 and 2012 were found to posses certain cell surface traits such as hydrophobicity, autoaggregation and/or high adhesive capacity suggesting potential immunomodulatory activity. However, application of the dorsal mouse air pouch system revealed that only the DC421, DC429 and 2035 strains exhibited strong immunostimulatory activity such as increased chemotaxis of polymorphonuclear (PMN) cells in association with increased phagocytosis and cytokine production. The same strains also induced immunomodulatory activity in the gut associated lymphoid tissue in mice in the absence of any inflammatory response. All strains induced IgA production while reduced TNFalpha production by small intestine cells. The strains DC421 and DC429 exerted their effect on the intestine through Toll-like receptor TLR2/TLR4/TLR9 mediated signalling events leading to secretion of a certain profile of cytokines in which gamma interferon (IFN-gamma), interleukin (IL)-5, IL-6 and IL-10 are included. The strain 2035 induced similar cytokine profile through the synergy of TLR2/TLR4. This study further supports the eligibility of the air pouch model to discriminate presumptive probiotic Lactobacillus strains exhibiting immunostimulatory activity in the gut. Furthermore, evidence is provided that the cell surface traits examined may not be the only criteria but an alternative and important component of a complex mechanism that enables a microorganism to interact with the host gut to exert its immunoregulatory activity.
