title: The ultrastructural immunocytochemical demonstration of erythropoietin receptors on developing erythrocytic cells of fetal mouse liver.
abstract: In spite of the severe restrictions imposed by the lack of high purity erythropoietin (Ep) and Ep specific antiserum wer have attempted to demonstrate presumptive Ep binding sites on the surface of developmental forms of erythrocytic cells of the mouse fetal liver using ultrastructural immunocytochemical methodology. Cells were exposed to exogenous Ep of differing potencies and concentrations and subsequently incubated in an Ep antiserum. The Ep-Ep-antiserum complex was then visualized with a gold-labeled IgG reagent. Limited surface labeling was noted on the developing erythrocytic cells and the evaluation of the mean surface labeling densities of the erythrocytic cell series indicated that the extent of labeling was related to the stage of maturation. Early polychromatophilic erythroblasts proved to be the most heavily labeled of the erythrocytic cells followed by the basophilic erythroblast, proerythroblast and late polychromatophilic erythroblasts respectively; normoblasts, reticulocytes and erythrocytes exhibited, at most, only minimal labeling. In addition, we have been able to demonstrate several primitive cells in the fetal liver which exhibited extensive surface labeling when compared with the developing erythrocytic cells. These cells may represent the erythroid precursors of the fetal liver.
mesh_terms: D000818:Animals; D004912:Erythrocytes / Q000378:metabolism*; D004921:Erythropoietin / Q000378:metabolism*; D005260:Female; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D006651:Histocytochemistry; D007158:Immunologic Techniques; D008099:Liver / Q000196:embryology* / Q000378:metabolism; D051379:Mice; D011247:Pregnancy; D011956:Receptors, Cell Surface / Q000378:metabolism*
chemical_list: D011956:Receptors, Cell Surface; D004921:Erythropoietin