Kiss of death

CD8 cytotoxic T cells are serial killers that slay one infected or cancerous cell after another. During each fatal encounter, an intercellular junction called the immunological synapse forms between killer and victim, according to researchers from Oxford University (Oxford, UK). Their work suggests new functions for the immunological synapse and supports the hypothesis that the immune system governs the number of cytotoxic T cells by “retiring” veterans of multiple battles.

In earlier studies immunological synapses were spotted only when an antigen- presenting cell met and activated a CD4 T cell. Although a CD8 cytotoxic T cell may attach to its victim for as little as two minutes, Gillian Griffiths and colleagues observed that synapses also formed during these contacts. The synapses have the characteristic bull's eye structure of a ring...