Non-radioactive cytotoxicity assays

A method for assessing cytotoxicity of an agent comprising:

• i) providing a target cell that has been engineered to express intracellularly a reporter;
• ii) exposing the target cell to an agent capable of modulating cytotoxicity;
• iii) assaying the activity of the reporter to obtain the reporter activity,
• wherein the reporter is not expressed endogenously by the target cell or is expressed endogenously by the target cell at a level lower than what is achieved by engineered expression;
• and
• wherein a change in the reporter activity relative to a reference value is indicative of the agent being able to modulate cytotoxicity of the target cell.