Exopolysaccharide from Lactobacillus rhamnosus KL37 Inhibits T Cell-dependent Immune Response in Mice

Area of Science:

• Immunology and Microbiology
• Bacterial Exopolysaccharides
• Inflammatory Disease Models

Background:

• Bacterial exopolysaccharides (EPSs) possess strain-specific immunomodulatory properties.
• Previous studies showed crude EPS from Lactobacillus rhamnosus KL37 ameliorated collagen-induced arthritis (CIA).

Purpose of the Study:

• To verify the anti-inflammatory properties of highly purified EPS from L. rhamnosus KL37 (EPS-37).
• To assess EPS-37's ability to suppress T cell-dependent humoral responses in a CIA model.

Main Methods:

• Active collagen-induced arthritis (CIA) model in mice immunized with type II collagen (CII) and lipopolysaccharide (LPS).
• Treatment with purified EPS-37 via intravenous and subcutaneous routes.
• Ex vivo and in vitro assessment of T-cell proliferation and cytokine production (Interferon-gamma [IFN-γ]).

Main Results:

• Intravenous EPS-37 markedly ameliorated arthritis and reduced CII-specific antibody production.
• Subcutaneous EPS-37 reduced clinical arthritis symptoms but not arthritogenic antibodies.
• EPS-37 inhibited T-cell proliferation and reduced IFN-γ production.

Conclusions:

• EPS-37 exhibits anti-inflammatory potential by inhibiting Th1-mediated inflammatory pathways.
• L. rhamnosus KL37 EPS may be useful for controlling T cell-dependent immune responses in inflammatory diseases.
• Optimal administration route for EPS-37 requires tailoring for specific disorders.