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Updated: Jun 17, 2026
Murine Model of Epicutaneously-Induced Immunomodulation
Published on: June 24, 2025
Immunomodulating effects of OM-89, a bacterial extract from Escherichia coli, in murine and human leukocytes
Wolfgang G Bessler1, Karola Puce, Ulrich vor dem Esche
1Institut für Molekulare Medizin und Zellforschung, Freiburg University Hospital, Freiburg, Germany. wolfgang.bessler@mol-med.uni-freiburg.de
Abstract:
OM-89 (Uro-Vaxom) is a bacterial extract prepared from 18 uropathogenic Escherichia coli strains used for the prevention and treatment of recurrent infections of the urinary tract. The immunomodulating effects of the bacterial extract were investigated in a mouse model. After a single oral administration of OM-89, leukocyte activation was demonstrated ex vivo in blood and liver cells using a chemiluminescence assay. An increase of the production of tumor necrosis factor-alpha (TNF-alpha) in supernatants of peritoneal cells was also observed. After repeated oral administration of OM-89, increased serum immunoglobulin G responses against several E. coli strains were found. Also, adjuvant properties of the extract using ovalbumin as an antigen could be demonstrated. In line with these findings in the mouse system, preliminary in vitro data obtained in the human system showed an increase in TNF-alpha and interleukin-6 production after stimulation of monocyte derived dendritic cells with OM-89. The activation of immune cells is likely to be mediated via Toll like receptors (TLRs); thus, the binding of components of the extract to TLR-4 and marginally to TLR-2 could be shown.
Insights
OM-89 (Uro-Vaxom), a bacterial extract, activates immune cells and enhances antibody responses, aiding in preventing recurrent urinary tract infections. It stimulates cytokine production and shows adjuvant properties, suggesting a role in immune modulation.
Area of Science:
- Immunology
- Microbiology
- Pharmacology
Background:
- Recurrent urinary tract infections (UTIs) are often managed with antibiotics.
- OM-89 is a bacterial extract derived from uropathogenic Escherichia coli strains.
- Its immunomodulating effects warrant investigation for UTI prevention and treatment.
Purpose of the Study:
- To investigate the immunomodulating effects of OM-89 in a preclinical mouse model.
- To explore the mechanisms underlying OM-89's immune activation, including cytokine production and antibody responses.
- To assess the potential of OM-89 as an immunomodulatory agent for UTIs.
Main Methods:
- Oral administration of OM-89 to mice.
- Ex vivo chemiluminescence assay to assess leukocyte activation.
- Measurement of tumor necrosis factor-alpha (TNF-alpha) production.
- Quantification of serum immunoglobulin G (IgG) responses.
- In vitro stimulation of human monocyte-derived dendritic cells.
- Analysis of Toll-like receptor (TLR) binding.
Main Results:
- Single oral OM-89 administration induced leukocyte activation in blood and liver cells.
- Increased TNF-alpha production by peritoneal cells was observed.
- Repeated administration led to enhanced serum IgG responses against E. coli strains.
- OM-89 demonstrated adjuvant properties with ovalbumin.
- In vitro human cell studies showed increased TNF-alpha and interleukin-6 production.
- Evidence of OM-89 binding to TLR-4 and TLR-2 was found.
Conclusions:
- OM-89 effectively modulates the immune system, enhancing both innate and adaptive responses.
- The bacterial extract activates immune cells, likely via Toll-like receptors (TLRs), particularly TLR-4.
- These findings support OM-89's potential as an immunotherapeutic agent for recurrent urinary tract infections.
