Fig 2: Immunostaining of ß-catenin in the placental tissue sections from normal and severe preeclampsia groups. Figure 3 A1 and A3 show the immunostaining of the ß-catenin in normal control (N) group; A2 and A4 show the immunostaining of the ß-catenin in severe preeclampsia (sPE) group. The staining intensity of ß-catenin in the placental tissue of the severe PE group (A2 and A4) was weaker than the control group (A1 and A3). B1 and B2: serial sections of A3 and A4 stained with HLA-G. STB = syncytiotrophoblast, EVT = extravillous trophoblast. Original magnification: 400× for A1 and A2, 200× for A3, A4, B1, B2.

Fig 3: Comparison of IHC staining results of HLA-ABC, HLA-G, and HLA-E in whole UC cross-sections at term and between 12 and 19 weeks, focusing on the AE and SAWJ. (A) IHC staining results of UC cross-sections at term are shown in the first row, and IHC staining results of UC between 12 and 19 weeks are shown in the second row. Red arrows: examples of cells in the SAWJ showing positive staining for the corresponding HLA of interest. (B) Negative control of term UC IHC staining results using an anti-mIgG1 antibody. (C) Negative control of 12–19-week UC IHC staining results using an anti-mIgG1 antibody. Scale bars = 50 µm.

Fig 4: Comparison of IHC staining results of HLA-ABC, HLA-G, and HLA-E in whole UC cross-sections at term and between 12 and 19 weeks, focusing on one of the umbilical vessels. (A) IHC staining results of term UC are shown in the first row, and IHC staining results of UC between 12 and 19 weeks are shown in the second row. (B) Negative control of term UC IHC staining results using an anti-mIgG1 antibody. (C) Negative control of 12–19-week UC IHC staining results using an ant-mIgG1 antibody. Scale bars = 50 µm.

Fig 5: Summary of the immunohistochemstry (IHC) staining results of HLA-ABC, HLA-G, and HLA-E in placental tissue sections at the decidua using the optimized primary antibody working concentrations. (A) Placental tissue sections at term and between 12 and 19 weeks stained with HLA-ABC (0.25 µg/mL), HLA-G (2.0µg/mL), and HLA-E (5.0 µg/mL). (B) Negative control of term placental IHC staining results using an anti-mouse IgG1 (mIgG1) antibody. (C) Negative control of 12–19 week placental IHC staining results using an anti-mIgG1 antibody. Scale bars = 100 µm.