IMMUNOFLUORESCENT IDENTIFICATION OF HUMAN MEGAKARYOCYTE COLONIES USING AN ANTI-PLATELET GLYCOPROTEIN ANTISERUM

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  • 1 January 1981
    • journal article
    • research article
    • Vol. 57  (2) , 277-286
Abstract
The development of a satisfactory in vitro assay system for human megakaryocyte colony forming progenitor cells was delayed by the lack of a suitable marker for cells of human megakaryocyte lineage. For this purpose an antiserum directed against a purified human platelet glycoprotein preparation was raised. In conjunction with indirect immunofluorescent staining of human bone marrow, this antiserum labeled only platelets, megakaryocytes and an infrequent population of small mononuclear cells. These small mononuclear cells, not otherwise identifiable as members of the megakaryocyte series, constituted 22.9% of the total fluorescein positive nucleated bone marrow cells. This antiserum was also used to label colonies cultured from human peripheral blood mononuclear cells using a modified plasma clot technique. A mean of 13 fluorescein-labeled colonies were cloned/106 mononuclear cells cultured. Granulocyte-macrophage and erythroid burst colonies did not label using this method. No augmentation of colony numbers was found with varying concentrations of erythropoietin, human embryonic kidney cell conditioned media (a source of thrombopoietin), or media conditioned by a human T lymphoblast cell line (a source of both colony stimulating and burst promoting activities). Immunofluorescent labeling for platelet glycoproteins is a convenient phenotypic marker for human megakaryocyte lineage cells useful in the study of in vitro human megakaryocytopoiesis.