Supplementary information

Supplementary information S1 (Figure) | Interactive version of a prototypical mature NK-cell lytic synapse

The mature natural killer (NK)-cell lytic synapse in FIG. 1 is provided in an interactive format, whereby placing the cursor over the cell and clicking the mouse button allows for the cell to be dragged in different directions for a full 360 degrees of interaction. The image shows a human NK cell (YTS cell line) expressing Cd2–GFP (green fluorescent protein) fusion protein conjugated to a target cell (an Epstein–Barr-virus-transformed B-cell line). NK cells were conjugated to the target cells, fixed, permeabilized and stained with a perforin-specific monoclonal antibody (red) to visualize the lytic granules. The serial images were obtained using confocal microscopy by serial acquisition of optical slices along the z-axis and followed by the three-dimensional reconstruction in silico. QuickTime virtual reality (QTvR) output and Improvision volocity visualization software were used to generate complete rotation of the images around the z-axis. The accumulated GFP fluorescence indicates the supramolecular activation cluster (SMAC) that forms at the synapse between the NK cell and the target cell. Notably, a region in the centre of the SMAC that is devoid of GFP is consistent with the presence of a central SMAC (cSMAC) and delineates a channel through which the secretion of lytic-granule contents is likely to occur. Although there is an accumulation of perforin inside the SMAC (consistent with the lytic granules surrounding the microtubule-organizing centre), perforin can be seen coming from this region to the cSMAC. This is consistent with the secretory domain of the lytic synapse.

Supplementary information S1 (Figure) | Interactive version of a prototypical mature NK-cell lytic synapse - Download Movie (60,174 KB)