When a receptor on the surface of a T cell – a sentry of the human immune system – senses a single particle from a harmful intruder, it immediately kicks the cell into action, launching a larger immune response. But exactly how the signal from a single receptor, among thousands on each T cell, can be amplified to affect a whole cell has puzzled immunologists for decades.
Now, Salk scientists have discovered the key to the amplification of an “invader” signal. The T cell receptor that detects the intruder turns into a mini-machine, activating and releasing copy after copy of a protein called ZAP70.
In the image here, single molecule tracks of Zap70 overlaid with T cell receptor microclusters shows signal transfer at early moments of T cell activation.
The finding, published in Nature Immunology, could help scientists design better immune-mediated treatments for cancer or autoimmune diseases.