Analysis and sorting of live cells according to secreted molecules, relocated to a cell-surface affinity matrix

We have developed a technology for analysis and sorting of live cells according to secreted molecules. An artificial affinity matrix, specific for the secreted product of interest, is created on the cell surface, and the cells are allowed to secrete for a defined time period. The secreted molecules bind to the affinity matrix on the secreting cell and are subsequently labeled with specific fluorescent or magnetic staining reagents for cytometric analysis and cell sorting. Crossfeeding of the secreted products to other cells is prevented by decreasing the permeability of the incubation medium. This approach will have a wide range of applications in biotechnology and biomedical research. Here, we describe analysis and sorting of hybridoma cells, according to secreted antibodies, and of activated T lymphocytes, according to secreted cytokines.