CD2 accumulates at both activating and inhibitory synapses.

<p>IL-2 activated polyclonal human NK cells were mixed with target cells at 37°C for 10 minutes, fixed, permeabilized, and stained with the cyt42/43 antiserum and a mAb to CD2 followed by the relevant secondary antibodies. Confocal microscope <i>z</i>-series were obtained. (A) Mixed with .221-Cw15 as indicated. A single confocal section is shown. The cell labeled #1, which displays KIR expression and clustering, represents an inhibitory synapse while cell #2, which lacks KIR2DL1 expression, displays an activating synapse. (B) Mixed with S2–LFA-3/Cw4 target cells, as indicated. A single confocal section is shown. (C) The fluorescence intensity was scanned around the perimeter of conjugated NK cells. Profiles labeled 1, 2, and 3 are from the corresponding cells in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0003278#pone-0003278-g002" target="_blank">Figures 2A and 2B</a>. The green and red lines represent the cyt42/43 and anti–CD2 fluorescence, respectively. Vertical red and blue lines mark the boundaries of cell contact as determined in DIC images. (D) Confocal <i>z</i>-stacks were used to create an <i>en face</i> view of the zone of cell contact in 2 inhibitory synapses.