Characterization of first trimester decidual tissue, primary HDSC and THESC using immunofluorescence and quantitative real-time PCR. Preparation of tissue sections, isolation of primary HDSC, cultivation of THESC and quantitative real-time PCR were performed as described in Materials and Methods. A) Immunofluorescence of decidual cells and tissue. First trimester decidual tissue isolated at 10th weeks of pregnancy, primary human decidual stromal cells at passage 3, and THESC are depicted. Double immunofluorescence staining with antibodies recognizing vimentin (red) and cytokeratin 7 (green) to detect stromal or epithelial cells, respectively, are shown. The respective counterstainings of tissues and cultures with DAPI are depicted on the right hand side. Representative pictures were taken at a 100-fold (decidual tissue) and 200-fold (cultivated cells) magnification, respectively. B) Quantitative real-time PCR measuring basal PRL and IGFBP1 mRNA expression in HDSC in a passage-dependent manner. For normalization values at passage 1 were arbitrarily set at 1. Bars represent mean values ± S.D. of four different experiments performed in duplicates. * indicates p < 0.05 compared to passage 1.