Intracellular cytokine staining for TGF-beta.

TGF-beta 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-beta in different cell types and situations. Most methods of measuring TGF-beta 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-beta in a mixture of cells. It is especially important to know the source and dynamics of TGF-beta secretion in cell culture studies since most cell types are known to be capable of producing TGF-beta. We describe here a technique of qualitative and quantitative measurement of TGF-beta production using flow cytometry. Previous work by others has led to the production of polyclonal and monoclonal antibodies to human and other mammalian TGF-beta. We have developed an intracellular cytokine staining for human TGF-beta using a monoclonal antibody, TB21.