Abstract

Cytotoxic T-lymphocytes (CTLs) are white blood cells in the human immune system that eliminate virally infected and tumourigenic cells. CTLs kill by delivering a cocktail of toxic substances that rapidly triggers a self-destruction programme (apoptosis) in the target cell. The release of these pro-apoptotic factors must be tightly controlled and only occurs once a well-sealed interface known as the ‘Immune Synapse’ is established between T-cell and its target. The study of several immunodeficiency conditions identified key parts of the protein machinery that is essential for CTL killing. It is furthermore known that calcium signalling is crucial to trigger and sustain a successful CTL attack and it has been suggested that global and local calcium fluxes in the T-cell drive multiple steps in this attack. However, it remains unclear what the exact timescales and magnitudes of calcium fluxes are and whether these might be changed when killing is impaired through genetic mutations or pharmacological inhibition. Using high speed live-cell imaging I followed the CTL attack on target cells in 4D to monitor and compare global calcium signals in healthy and mutant CTL .