THE ULTRASTRUCTURAL, IMMUNO-CYTOCHEMICAL DEMONSTRATION OF ERYTHROPOIETIN RECEPTORS ON DEVELOPING ERYTHROCYTIC CELLS OF FETAL MOUSE-LIVER

  • 1 January 1980
    • journal article
    • research article
    • Vol. 8  (8) , 1063-1074
Abstract
In spite of the severe restrictions imposed by the lack of high purity erythropoietin (Ep) and Ep specific antiserum, an attempt was made 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 an Au-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. Several primitive cells which exhibited extensive surface labeling when compared with the developing erythrocytic cells were also demonstrated in the fetal liver. These cells may represent the erythroid precursors of the fetal liver.