Measurement of tumor necrosis factor alpha and beta

Tumor necrosis factor (TNF) a and b are multifunctional cytokines elaborated primarily by monocytes and macrophages (TNF-a) or T cells (TNF-b). Some cells that bind TNF-a or -b on their surface receptors lyse as a consequence of the binding reaction. This unit presents a protocol that employs TNF-sensitive, actinomycin D-treated murine L929 fibroblasts to quantify TNF activity in supernatants derived from cell cultures, serum samples, or cerebral spinal fluid. While the assay can measure picogram concentrations of human, rat, and murine TNF-ab, it cannot distinguish between the a and b forms of any species. A describes propagation and preparation of L929 fibroblasts.