title: The production of terminal deoxynucleotidyl transferase (TdT) positive cells in cultures of human pluripotent hemopoietic progenitor cells.
abstract: A transient increase in terminal deoxynucleotidyl transferase positive (TdT+) cells was observed during the early phase of (less than or equal to day 5) cultures supporting the growth of pluripotent myeloid progenitor cells (CFU-mix). T-cell growth-promoting medium and erythropoietin were not required. The rapidity with which TdT+ cells appeared in cultures and the results of cultures where TdT+ cells were high initially (greater than 800 cells/culture) were not consistent with their having been produced by proliferation of pre-existing TdT+ cells from the bone marrow inoculum. The results suggest production of TdT+ cells from a TdT-negative precursor either by altered enzyme expression or by production of TdT+ progeny.
mesh_terms: D002455:Cell Division; D002478:Cells, Cultured; D004253:DNA Nucleotidylexotransferase / Q000378:metabolism*; D004254:DNA Nucleotidyltransferases / Q000378:metabolism*; D004921:Erythropoietin / Q000494:pharmacology; D006412:Hematopoietic Stem Cells / Q000201:enzymology*; D006801:Humans; D010835:Phytohemagglutinins / Q000494:pharmacology
chemical_list: D010835:Phytohemagglutinins; D004921:Erythropoietin; D004254:DNA Nucleotidyltransferases; D004253:DNA Nucleotidylexotransferase