Figure 2

P69 are more susceptible to NK cells than M12. (a) Human NK cell cytotoxicity to P69, M12 and K562 (as a positive control) was assessed by calcein release assays in various E/T ratios as described in Materials and Methods section. Data are the mean±S.E.M. of three independent experiments. (b) The mixtures of NK cells and P69 or M12 at an E/T ratio of 1:2 were incubated at 37 °C for 2 h and then stained for CD107α and CD56. The gated on CD56-posivtive cells were analyzed and the numbers in boxes indicated percentage of CD107α-positive NK cells. The data are representative of three separate experiments (left graph). Data were the mean±S.E.M. of three independent experiments (right panel). (c) Polarization of perforin-containing granules in NK cells against P69 or M12 were expressed as percentage of NK cells showing polarized perforin. Data are the mean±S.E.M. from three independent experiments. (d) The conjugate formation of NK cells with P69 or M12 at indicated time points was identified by flow cytometry. The gated on CD56-posivtive cells were analyzed and the numbers in different quadrants indicated percentage of cells. One representative experiment out of three was shown (left graph). The fraction of two-colour NK cells was analyzed and data are the mean±S.E.M. of three independent experiments (right panel). (e) P69 (left panel) or M12 (right panel) was supplemented by the media harvested from 48-h cultural supernatants of P69 or M12 cultures and then calcein release assay was performed at an E/T ratio of 5–1. Data are the mean±S.E.M. of three independent experiments