Immunocytochemical localization of growth factors and their receptors in human pre-embryos and Fallopian tubes

We utilized indirect immunocytochemistry to demonstrate thepresence of growth factors and their receptors in human pre-embryosand Fallopian tubes. In pre-embryos, only transforming growthfactor- (TGF-) and the intracellu-lar domain of epidermal growthfactor receptor (EGFR) were found at the 4-cell stage. In 8-to 14-cell pre-embryos, TGF-, the intracellular and extracellulardomains of EGFR, and insulin-like growth factor-I and its receptorwere found. Antibodies against TGF- stained all Fallopian tubespecimens, while the extracellular domain of EGFR was only foundin specimens from patients with either blood type A or AB. Theseresults suggest a cross-reactivity between the extracellulardomain of the EGFR and blood group antigens. Our novel demonstrationof growth factor receptor staining in human pre-embryos showsthat growth factor receptor localization is dependent on thedevelopmental stage of human pre-embryos. We have also establisheda potentially important link between the Fallopian tube whichsecretes growth factors and the localization of growth factorreceptors in pre-embryos. These findings are compatible withthe hypothesis that tubal secretions are embryotrophic for theearly development of the pre-embryo.