Complex formation between
NK-92 cells and Raji cells investigated
by confocal microscopy. Raji cells and NK-92 cells were coincubated
for 1 h, fixed, permeabilized, and stained for perforin (red) to identify
cytotoxic granules. Cell nuclei were labeled with DAPI (blue). Scale
bar: 10 μm. (A) Representative images of cell–cell complex
formation. (B) Perforin (red) fluorescence quantification. P = 0.0071. Mean with SD are presented for n = 3. Statistical significance was assessed using Student’s t test. In all figures, ns, P > 0.05;
*, P < 0.05; **, P < 0.01;
***, P < 0.001.