Intracellular cytokine staining for TGF-β

TGF-β is a well-described immunoregulatory molecule that is produced by most cell types. Many studies have been aimed at investigating the role played by TGF-β in different cell types and situations. Most methods of measuring TGF-β have previously relied on enzyme-linked immunosorbent assay (ELISA) or assays of its anti-proliferative effects on various cell lines. Both assays, though useful, cannot be used to effectively identify the cells that are producing TGF-β in a mixture of cells. It is especially important to know the source and dynamics of TGF-β secretion in cell culture studies since most cell types are known to be capable of producing TGF-β. We describe here a technique of qualitative and quantitative measurement of TGF-β production using flow cytometry. Previous work by others has led to the production of polyclonal and monoclonal antibodies to human and other mammalian TGF-β. We have developed an intracellular cytokine staining for human TGF-β using a monoclonal antibody, TB21.