Fig. 4

Antibody-mediated blocking experiments showing natural killer (NK) cell activating and inhibiting receptors mediating DPMSC lysis. NK cells were preincubated with antibodies specific to the indicated NK cell activating and inhibiting receptors; NK cells were then cocultured with DPMSCs at a 10:1 NK:DPMSC ratio in a cytolytic assay. DPMSC lysis by NK cells was evaluated using microscopic examination within 24 h. Representative phase-contrast microscopic images show complete lysis of DPMSCs (no sign of intact adherent DPMSCs, cells were ruptured, and cellular debris was obvious in suspension (arrowheads) by untreated NK cells (NK cells were initially activated with 100 U/ml IL-2 for 72 h), by NKp46, by DNAM, and moderate lysis by CD69, and inhibition of lysis by NKp30, NKG2D, and NKp44 (arrows point to adherent DPMSCs). Blocking CD94 receptor did not increase cytolytic activity of NK cells. Experiments were carried out in triplicate and repeated 10 times using NK cells and DPMSCs prepared from the peripheral blood of 10 different healthy donors and 10 different fetal membranes, respectively. Scale bars = 50 μm My answer to AQ3: the lysis was 100% and the correct arrows should be arrowheads point at cell suspenstion as corrected in the text. Modified figure is attached