Abstract
The therapeutic agent OM-89 (Uro-Vaxom®) contains lyophilized immunostimulating fractions
from 18 Escherichia coli strains. It has been shown to provide protection against recurrent urinary tract
infections in humans and against bacterial infections in mice. Here the immuno-stimulatory
properties of OM-89 were investigated by in vitro and in vivo assays. in vitro the activation of murine spleen cells by the AlamarBlueTM assay was determined. OM-89
was effective in stimulating the metabolism of spleen cells within a concentration
range of 0.625 -2.5 mg/ml. The activation of murine bone marrow-derived macrophages
by OM-89 was shown by the induction of NO production; OM-89 was a most effective stimulant
at concentrations around 6 mg/ml. In the human system, the effect of OM-89 was tested
in vitro: the metabolic activity of peripheral blood lymphocytes (PBL) was stimulated starting
at concentrations of approx. 250 μg/ml, and the spontaneous apoptosis of polymorphonuclear
neutrophils (PMN) was reduced starting at OM-89 concentrations of approx. 100 μg/ml.
Finally, in a mouse model, the in vivo protection of mice against infection with Salmonella typhimurium after the oral administration of OM-89 was tested (100 mg in a volume of 0.5 ml once
a day for 10 consecutive days). The extract proved to be effective: 90 % of the OM-89-treated
animals survived compared to 58 % of the untreated control group.
Key words
Bacterial extract - Immunostimulation - OM-89 - Urinary tract infections - Uro-Vaxom®
- Vaccination