On a small sample volume containing few cells and heterogeneous cell populations, flow cytometry allows to analyze with high sensitivity the cell size, its contents and the intensity of these stained cells.
Although in current practice of immunophenotyping flow cytometers are mainly used to differentiate positive and negative staining of cells, BioCytex uses these same instruments to quantitate molecules bound on cells, receptors, ligands or drugs as well as intracellular targets.
Quantitative flow cytometry is achieved by comparing fluorescence intensity and a calibration standard.
BioCytex uses a calibrator made of a mix of bead populations . These calibration beads are coated with known and increasing numbers of immunoglobulins (IgG) bound to their surface thus mimicking the binding of specific monoclonal antibodies to the biological sample cells.
Then, this calibrator and the target stained cells are incubated with polyclonal antibodies labeled with FITC fluorochrome.
The beads bear specific number of sites and will allow to draw a calibration curve relating mean fluorescence intensity into a number of receptors per cell. The mean fluorescence intensity (MFI) of the tested sample is reported on the calibration curve to determine the number of molecules expressed per cell. Non specific staining is evaluated using an irrelevant antibody (negative isotypic control).
These requirements has led BioCytex to the development of kits including all necessary reagents, not only calibrators but also antibodies, buffers, agonists and a written procedure for in vitro diagnostic use of these applications.
The Biocytex product line can be categorized as follows:
Numerous biological molecules present an interest in the measurement of their expression level. Indeed any modulation of receptor expression level associated to physiological differentiation, pathological state or therapeutic treatment brings valuable information to the biologists and the physicians.
Such measurements in Clinical Biology require full reliability in term of day to day, inter instrument and lab-to-lab reproducibility.
As an example, an ambulatory patient treated with a new generation of antiplatelet drugs will be easily monitored wherever he travels.