Fig 5. Targets for SALSA in human placenta.

To determine further binding sites for SALSA in the placenta, SALSA containing AF was added as an overlay to frozen placental sections prior to detection of SALSA by fluorescence immunohistochemistry. The addition of the SALSA containing overlay (A) revealed a strong binding of SALSA to numerous additional structures in the placenta which were not observed without the overlay (B). SALSA binds to the endothelium of most capillaries (Ca) and larger vessels (Ve) as well as to most of the syncytiotrophoblast layer (A). Without overlay SALSA staining is much more sporadic or lacking in these structures (B). The strong binding after ex vivo addition of SALSA suggests that the focal staining observed in the absence of overlay (Fig 2) is a result of limited availability of SALSA rather than the lack of interacting tissue components. 400× magnifications.