Cytotoxicity of NK cells in scrub typhus patients.

<p>Panel A and B: NK cytotoxicity. Freshly isolated PBMCs (panel A) or purified NK cells (panel B) from 30 HCs and 20 patients with scrub typhus were cocultured with K562 cells for 4 hours, and then stained with FITC-conjugated anti-CD45 mAb and PI. Cytotoxicity was determined as the percentage of apoptotic K562 cells by flow cytometry. Panel C: CD107a expression in NK cells. PBMCs obtained from 15 HCs and 15 patients with scrub typhus patients were stained with FITC-conjugated anti-CD107a or isotype control mAbs and then incubated with K562 cells. After 1 hour, monensin was added and the cells were incubated for an additional 4 hours. The cells were then stained with PerCP-conjugated anti-CD3 and PE-conjugated anti-CD56 mAbs, and then CD107a expression in NK cells was analyzed by flow cytometry. Symbols represent individual subjects and horizontal lines indicate median values. ns = not significant by the ANCOVA test. Panel D: NK cell cytotoxicity of purified CD69- and CD69+ NK cell subsets in scrub typhus patients. Results are representative of 3 independent experiments.