Search

A highly sensitive test system, based on the immuno-PCR method, was developed for the detection of two staphylococcal toxins: enterotoxin A (SEA) and toxic shock syndrome toxin (TSST). A key element of the developed systems was to obtain supramolecular complexes of bisbiotinylated oligodeoxynucleotides and streptavidin, which were to be used as DNA-tags. Specificity studies showed no cross-reactivity when determining SEA and TSST. The sensitivity of detection of these toxins in the culture supernatants S. aureus was not lower than 10 pg/mL.

We propose a method of quantitative functional activity assessment in cells isolated via sorting on a flow cytometer. We show that cell populations vary in the mRNA expression of cytokine genes immediately after isolation and sorting, while the maintenance of homogenous populations in culture without stimulation results in an increase in these gene mRNA expression. Using the original system, it is now possible to detect mRNA cytokine genes with high sensitivity, starting from 90 cells per specimen. This approach permits genetic and immunogenetic analysis of gene expression with the goal of determining their functions in the in vitro studies.

The virus particles of live mumps virus vaccine widely used for vaccination in Russia have been detected and visualized by the atomic force microscopy. For quantitative estimation of the number of observed virus particles the special method has been developed. The presence of the vaccine virus protein component was tested by ELISA and dot-blot analysis. Using a quantitative real-time PCR assay the number of copies of viral RNA was estimated. The results of the quantitative estimation obtained by real-time PCR corresponded to the atomic force microscopy data.

The accuracy of a real-time polymerase-chain-reaction assay for genetically modified sources in food products was determined using two official test systems (kits) of primers and samples. These kits were recommended by the Federal Center of State Sanitary and Epidemiological Surveillance (Russian Ministry of Health) and the European Commission. We used the following three models of thermocyclers: iCycler iQ (Bio-Rad, United States), Rotor-Gene 3000 (Corbett Research, Australia), and DT-322 (DNA-Technology, Russia). Studies of samples that contained 1% genetically modified sources showed that the error of a quantitative assay for genetically modified sources in food products corresponds to 20–30% and does not depend on the kit type and the thermocycler model used.