For cytofluorimetric analysis (FACSCalibur, Becton Dickinson

& Co, Mountain View, CA, USA), cells were stained with the appropriate unlabeled mAbs followed selleck kinase inhibitor by PE-conjugated isotype-specific goat anti-mouse secondary Ab (Invitrogen-Life Technologies, Carlsbad, CA, USA; Southern Biotechnology Associated, Birmingham, AL). For the evaluation of apoptotic/dead cells, the AV/PI staining kit (Bender Systems, Wien, Austria) was used following the manufacturer instructions. The gating strategies to assess AV/PI staining or to evaluate NK-receptor expression are shown in Supporting Information Fig. 3. For CD107 mobilization, 2 × 105 NK cells cultured in IL-2 either under hypoxic or normoxic conditions were cocultured with 2 × 105 target cells (FO-1 or P815 cells) in 96 V-bottom well

plates. PE-conjugated Selleck Selumetinib anti-CD107a mAb was added in each well at the onset of the coculture. NK cells and target cells were coincubated for 4 h at 37°C in 5% CO2; after the first hour of coincubation, Golgi Stop (Becton Dickinson) was added. Cells were then washed in PBS with 2 mM EDTA and stained with the appropriate fluorochrome-conjugated mAbs. Analysis of CD107a surface expression in NK cells mixed with FO-1 cell line was done on cells double-stained with FITC-conjugated anti-CD45 and allophycocyanin-conjugated anti-CD56 mAbs. To detect spontaneous degranulation, a control sample without target cells was included. NK-cell incubation with the FcγR+ P815 murine cell line was done either in the absence or in the presence of IgG1 mAbs P-type ATPase specific for the receptors indicated in the text. Analysis of CD107a surface expression in NK cells mixed with P815 cell line was

done on cells stained with APC-conjugated anti-CD56 mAb. NK-cell populations were tested for cytolytic activity in a 4-h 51Cr-release assay against either two human melanoma cell lines (i.e. FO-1 and MeCoP), the B-EBV cell line 721.221 (i.e. 221), or the FcγR+ P815 murine cell line. The concentration of the various mAbs added in the redirected killing and in the ADCC experiments was 1 μg/mL. The E:T ratios are indicated in the figures. Statistical analyses were performed using the Prism software package (release 5.00; GraphPad Software). Statistical significance was evaluated by two-tailed paired Student’s t-test. A p value of less than 0.05 (*), less than 0.01 (**), or less than 0.001 (***) was considered statistically significant. This work was supported by grants awarded by Associazione Italiana per la Ricerca sul Cancro (A.I.R.C.): IG project numbers 5282 (M.V.), 10565 (L.V.), 10225 (L.M.), MFAG project number 6384 (G.P.), and “Special Program Molecular Clinical Oncology 5×1000” project number 9962 (L.M.); Ministero dell’Istruzione, Università e Ricerca (MIUR): MIUR-FIRB 2003 project RBLA039LSF-001 (L.M.