Accelerated ⁸⁶Rb⁺ (K⁺) release from the cytotoxic T lymphocyte is a physiologic event associated with delivery of the lethal hit

Cloned CTL have been loaded with the K⁺ analogue ⁸⁶Rb⁺. When mixed with unlabeled target cells, accelerated ⁸⁶Rb⁺ release occurs from the CTL. The magnitude of accelerated ⁸⁶Rb⁺ release is proportional to the efficacy of the target in standard ⁵¹Cr release assays. The signal responsible for accelerated ⁸⁶Rb⁺ release has been localized to a postbinding event and has the physiologic requirements of delivery of the lethal hit. Thus, accelerated ⁸⁶Rb⁺ release from the CTL represents the first direct observation of a physiologic event within the CTL related to a functional CTL-target interaction.