Functional characterization of pro-biotic pharmaceuticals by quantitative analysis of gene expression

Functional characterization and quality control of complex biological pharmaceuticals are currently difficult to achieve. Classical analytical methods are not suitable due to the heterogeneity of such substances. Conventional biological assays based on the detection of proteins and functional physiologic responses are highly variable in sensitivity and therefore, difficult to standardize. The quantification of expressed genes in contrast, does not require the accumulation of measurable protein and hence is a more sensitive and dynamic method for the functional characterization of complex biological substances. This report describes a standardized system based on real-time polymerase chain reaction (PCR), which allows a reliable stability monitoring and quality control of such preparations, as exemplified by three pro-biotic pharmaceuticals that contain living bacteria of Enterococcus faecalis (Symbioflor-1), Escherichia coli (Symbioflor-2) and a preparation of sterile autolysate of both species (Pro-Symbioflor). This system might be universally applicable to characterize complex biological pharmaceuticals by selecting appropriate sets of target cells and regulated genes.