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Polycythaemia vera. IV. Specific binding of stem cell factor to normal and polycythaemia vera highly purified erythroid progenitor cells
Author(s) -
Dai ChunHua,
Krantz Sanford B.,
Koury Stephen T.,
Kollar Kathleen
Publication year - 1994
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.1994.tb05065.x
Subject(s) - polycythaemia , polycythemia vera , stem cell , progenitor cell , haematopoiesis , immunology , hematology , medicine , cancer research , biology , genetics
Summary. Polycythaemia vera (PV) patients' blood burstforming units‐erythroid (BFU‐E) have an enhanced sensitivity to stem cell factor (SCF) compared to normal BFU‐E. To characterize SCF receptors on erythroid progenitors from normal individuals and PV patients, we performed binding experiments using radioiodinated recombinant SCF (rSCF), day 1 BFU‐E and day 8 erythroid colony‐forming cells (ECFC), which are mostly colony‐forming units‐erythroid (CFU‐E). 125 I‐rSCF binds to a single class of cell surface receptors (23 000/ECFC) at 0d́;C with a high‐binding affinity (K d = 17pm). Saturation occurred at 0.5 nm (10ng/ml) which produces a nearly maximum biological effect. One half of the radiolabelled rSCF was internalized by the cells after 30 min at 37d́;C. No significant differences in the receptor number, dissociation constant, or internalization rate were found between normal and PV ECFC. Autoradiographic analysis of 125 I‐rSCF binding to normal BFU‐E and ECFC showed that no differences were present in either the percentage of positive cells or the number of radioactive grains/cell between the normal and PV erythroid progenitors. The enhanced sensitivity of PV BFU‐E and CFU‐E to SCF does not appear to be related to changes in SCF receptor number, binding affinity or internalization and the hypersensitivity of PV erythroid progenitors to SCF must reside in a further internal cellular abnormality.