Abstract: To overcome the difficulty in achieving a quantitative assessment of CTL function in clinical settings, the inventors aimed at developing a new method inspired by their knowledge of the CTL/tumor target biology and based on flow cytometry. In particular, to directly detect the earliest steps of tumor cell resistance to CTL attack at the lytic synapse the inventors developed a method to monitor CTL/tumor cells interaction in the presence of FM1-43, a fluorescent lipophilic dye that rapidly intercalates into lipid bilayer during the membrane turnover that accompanies plasma membrane reparation. This assay allows the inventors to measure reparative membrane turnover of tumor cells under CTL attack by FACS analysis at the whole tumor cell population level. They initially applied this approach to compare the response of melanoma cell (D10 cells) to CTL attack as compared to conventional target cells that are sensitive to CTL mediated cytotoxicity (EB V-transformed B cells, JY cells).

Abstract: The present invention relates to methods and kits for detecting basophil cells activation. The inventors showed that fluorescent avidin binds to basophil cell surface upon degranulation and that this probe can be used to monitor basophil degranulation More specifically the present invention relates to methods for monitoring of basophil degranulation using avidin-based probes. The method of the invention described here allows to measure direct basophil degranulation following Fc?RI crosslinking with allergen. This method provides a direct measurement of degranulation by staining exteriorized granules and unambiguously detects activated basophils degranulated. The extent of the degranulation can be directly deduced from the intensity of fluorescence of fluorochrome-labelled avidin measured on basophils. When applied to allergic patient samples the avidin-based method detected efficiently specific basophil responses.