Measurement of human interleukin 11

This unit describes an ELISA and a cell proliferation assay that can be used, respectively, to measure the protein level or biologic activity of human and murine interleukin 11 (IL-11). The bioassay is based on the ability of IL-11 to support growth of the B9-11 cell line, a subline of B9 that has traditionally been used to measure levels of IL-6. B9-11 is substantially more responsive to IL-11 than the T10 line used in older protocols. This new bioassay therefore provides improved sensitivity, with a detection limit of 20 pg/ml. An alternate procedure is provided that employs neutralizing antibodies in the cell proliferation bioassay to use to ensure that the activity of the desired molecule (IL-11) is being measured in samples containing multiple cytokines. A describes maintenance of B9-11 cells.