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T Yokochi, M Brice, PS Rabinovitch, T Papayannopoulou and G Stamatoyannopoulos
Two new cell surface antigens specific for the erythroid lineage were
defined with cytotoxic IgM monoclonal antibodies (McAb) (EP-1; EP-2) that
were produced using BFU-E-derived colonies as immunogens. These two
antigens are expressed on in vivo and in vitro derived adult and fetal
erythroblasts, but not on erythrocytes. They are not detectable on resting
lymphocytes, concanavalin-A (Con-A) activated lymphoblasts, granulocytes,
and monocytes or granulocytic cells or macrophages present in peripheral
blood or harvested from CFU-GM cultures. Cell line and tissue distributions
distinguish McAb EP-1 and EP-2 from all previously described monoclonal
antibodies. McAb EP-1 (for erythropoietic antigen-1) inhibits the formation
of BFU-E and CFU-E, but not CFU-GM, colonies in complement-dependent
cytotoxicity assays. By cell sorting analysis, about 90% of erythroid
progenitors (CFU-E, BFU-E) were recovered in the antigen-positive fraction.
Seven percent of the cells in this fraction were progenitors (versus 0.1%
in the negative fraction). The expression of EP-1 antigen is greatly
enhanced in K562 cells, using inducers of hemoglobin synthesis. McAb EP-2
fails to inhibit BFU-E and CFU-E colony formation in complement-dependent
cytotoxicity assays. EP-2 antigen is predominantly expressed on in vitro
derived immature erythroblasts, and it is weakly expressed on mature
erythroblasts. The findings with McAb EP-1 provide evidence that erythroid
progenitors (BFU-E and CFU-E) express determinants that fail to be
expressed on other progenitor cells and hence appear to be unique to the
erythroid lineage. McAb EP-1 and EP-2 are potentially useful for studies of
erythroid differentiation and progenitor cell isolation.
This article has been cited by other articles:
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| Copyright © 1984 by American Society of Hematology Online ISSN: 1528-0020 | |||||||||
