Abstract: The invention provides an assay-ready frozen eukaryotic cell (stored frozen) in a composition that includes a cryopreservative and an inhibitor of xanthine oxidase, a kit containing a plurality of the assay-ready frozen eukaryotic cell, and a method of preparation thereof to minimize the variability in the performance of the cell, particularly in terms of undesirable intra- and inter-assay variability.

Abstract: The present invention provides a cell for use in a one-step cell-based assay for an extracellular ligand (e.g., IFN?) that initiates a ligand-specific signal at the nucleus of the cell and for neutralizing antibodies against the extracellular ligand. The cell-based one-step assay allows both the extracellular ligand concentration and the neutralizing antibody titer to be quantified in a single sample (e.g., serum) without the need for sample dilution and addition of exogenous extracellular ligand.

Abstract: The present invention relates to a commercializable cell and to a gene reporter assay method and a kit which use this cell to determine the presence and/or the level of a molecule that activates signal transduction activity of a cell surface protein. This cell is treated in such a manner that it will have a sufficiently long shelf life for its intended purpose, whereupon at the end of its useful shelf life or at the end of its use, i.e., in an assay, the cell undergoes cellular death.

Abstract: A method for conducting a neutralization assay for the determination of the titer of antibodies in a sample is provided which is an improvement over existing neutralization assays because the sensitivity of the reporter gene assay to determine neutralization is increased by the use of a “one time use” cell line transformed with a reporter gene construct. The titer is determined for antibodies specific for a predetermined target molecule that activates the signal transduction activity of a cell surface protein or a pattern recognition receptor or are specific for an antagonist for the predetermined target molecule.

Abstract: The present invention provides a cell for use in a one-step cell-based assay for an extracellular ligand (e.g., I FN?) that initiates a ligand-specific signal at the nucleus of the cell and for neutralizing antibodies against the extracellular ligand. The cell-based one-step assay allows both the extracellular ligand concentration and the neutralizing antibody titer to be quantified in a single sample (e.g., serum) without the need for sample dilution and addition of exogenous extracellular ligand.

Abstract: The present invention relates to a commercializable cell and to a gene reporter assay method and a kit which use this cell to determine the presence and/or the level of a molecule that activates signal transduction activity of a cell surface protein. This cell is treated in such a manner that it will have a sufficiently long shelf life for its intended purpose, whereupon at the end of its useful shelf life or at the end of its use, i.e., in an assay, the cell undergoes cellular death.

Abstract: A method for conducting a neutralization assay for the determination of the titer of antibodies in a sample is provided which is an improvement over existing neutralization assays because the sensitivity of the reporter gene assay to determine neutralization is increased by the use of a “one time use” cell line transformed with a reporter gene construct. The titer is determined for antibodies specific for a predetermined target molecule that activates the signal transduction activity of a cell surface protein or a pattern recognition receptor or are specific for an antagonist for the predetermined target molecule.

Abstract: The present invention relates to a commercializable cell and to a gene reporter assay method and a kit which use this cell to determine the presence and/or the level of a molecule that activates signal transduction activity of a cell surface protein. This cell is treated in such a manner that it will have a sufficiently long shelf life for its intended purpose, whereupon at the end of its useful shelf life or at the end of its use, i.e., in an assay, the cell undergoes cellular death.

Abstract: The present invention relates to a commercializable cell and to a gene reporter assay method and a kit which use this cell to determine the presence and/or the level of a molecule that activates signal transduction activity of a cell surface protein. This cell is treated in such a manner that it will have a sufficiently long shelf life for its intended purpose, whereupon at the end of its useful shelf life or at the end of its use, i.e., in an assay, the cell undergoes cellular death.