The present disclosure relates to methods for transiently activating temperature-sensitive agents in one or more cells, for example by contacting one or more cells with a temperature-sensitive agent and transiently incubating the cells at a permissive temperature for inducing an activity of the temperature-sensitive agent in the cells. Additionally, the present disclosure relates to methods of contacting one or more cells in a subject with a temperature-sensitive agent and then lowering the subject's core body temperature to a permissive temperature for inducing an activity of the temperature-sensitive agent in the cells. The disclosure also relates to methods of contacting one or more cells in a subject with a temperature-sensitive agent, maintaining the subject's surface body temperature at a permissive temperature for inducing an activity of the temperature-sensitive agent in the cells. Further disclosed are methods of treating a subject with a temperature-sensitive therapeutic agent.