Calcium response to erythropoietin in erythroleukemia cells.
Erythroleukemic mouse spleen cells were analyzed by flow cytometry at three fluorescence wavelengths, two emissions for the calcium indicator indo 1 and immunofluorescence with an antiserum directed against murine leukemia retrovirus antigen. The antigen-positive subpopulation of cells responded to EPO by transiently changing indo 1 fluorescence emissions, indicating a change in cytoplasmic calcium concentration. EGTA blocked the EPO response, suggesting that Ca2+ influx may have followed EPO exposure in these cells. Antigen-negative cells showed no Ca2+ response to EPO. Infected mice all contained antigen-positive spleen cells, but, as measured by changes in indo 1 fluorescence, these subpopulations varied in their ability to respond to EPO.
Worthington
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Department of Medical Biology, University of Tennessee Medical Center, Knoxville 37920-6999.
D000818:Animals; D000956:Antigens, Viral / Q000032:analysis; D002118:Calcium / Q000502:physiology*; D004921:Erythropoietin / Q000494:pharmacology*; D005434:Flow Cytometry; D005622:Friend murine leukemia virus / Q000276:immunology; D004915:Leukemia, Erythroblastic, Acute / Q000503:physiopathology*; D051379:Mice; D014407:Tumor Cells, Cultured
D000956:Antigens, Viral; D004921:Erythropoietin; D002118:Calcium