Figure 4

Immunohistochemical localization of Cripto in endometrium across the menstrual cycle. (A) Late secretory human endometrial tissue (lanes 2 and 3) was analysed by SDS-PAGE and Western blot using a Cripto-specific antibody. A 28 kDa band was detected in the absence (lane 2) but not the presence (lane 3) of a blocking protein. Recombinant Cripto (lane 1) was included as a positive control. The Cripto monoclonal antibody was used to localize Cripto in early proliferative (B), mid proliferative (C), early secretory (D), mid secretory (E & G) and menstrual phase (F) endometrium. Immunostaining for GRP78 in mid secretory endometrium (H) indicated that its expression coincided with that of its binding partner, Cripto. Negative controls for immunostaining by replacement of antisera with goat IgG at a matching concentration are shown in insets. Arrowhead (G) indicates specific Cripto staining in endothelial cells during the mid secretory phase. Bar, 50 μm. Scale bar on (B) relates to panels (B-F), whereas scale bar on (G) relates to panel (G & H). Tissue sections were also scored according to Cripto staining intensity within endometrial stroma (I) and epithelial glands (J). Intensity of staining is shown as individual (filled circles) and mean scores (H & I).