Figure 1: Differential expression of NCR isoforms by dNK and pNK cells results in differential activation on receptor cross-linking.

(a,b) mRNA was extracted from freshly isolated dNK and pNK cells from the same donor (ten matched donor samples). Quantitative reverse-transcription PCR was used to measure the relative expression of the three NKp30/NCR3 (a) and NKp44/NCR2 (b) splice variants. Data are representative of ten independent donors. Bar graphs show mean values±s.e.m. *P<0.05 and **P<0.01; NS, not significant; Student’s t-test. (c,d,e) Freshly isolated dNK and pNK cells cultured overnight with IL15 (10 ng ml⁻¹) were stimulated for 4 h with a single or combination of two specific monoclonal antibodies, used as ligands. (c) NK cell degranulation was assessed by quantification of CD107a cell surface expression using flow cytometry on CD3^negCD56^pos cells. (d) Percentage of freshly isolated dNK cells and (e) pNK cells showing CD107a surface expression. Results are presented as mean values±s.e.m. from four independent donors. *P<0.05, **P<0.01, ***P<0.001; NS, not significant; one-way analysis of variance with Bonferroni post test. (f,g) Representative experiment showing the kinetics of intracellular perforin expression monitored for 8 h in the presence of polyclonal stimulation with ionomycin/phorbol myristate acetate (PMA; n=4). The percentage of NK cells expressing perforin is given above each FACS histogram; MFI values are shown in brackets.