Murine KIT+ lineage- bone marrow progenitors express Fc gamma-RII but do not express Fc epsilon-RI until mast cell granule formation.
We examined the expression of Fc epsilon-RI and Fc gamma-RII/III on mouse bone marrow cells enriched for hematopoietic progenitors including mast cell progenitors. Bone marrow cells were depleted of mature hematopoietic lineages and a primitive population of cells that express the proto-oncogene c-kit (KIT+ lineage- cells) was isolated. KIT+ lineage- cells stain positively using the Ab 2.4G2, indicating surface expression of Fc gamma-RII and/or Fc gamma-RIII. Fluorescent staining of intracytoplasmic domains of Fc gamma-RII and Fc gamma-RIII revealed that these cells express primarily Fc gamma-RII on their surface. KIT+ lineage- cells did express Fc gamma RIII alpha-chain protein, but predominately in the nuclear/perinuclear area. We could not detect surface expression of Fc epsilon-RI by KIT+ lineage- cells, although a heterogeneous population of KIT- cells does bind IgE with high affinity and may reflect cells of the basophilic lineage. KIT+ lineage- cells cultured with SCF and IL-3 generate numerous mast cells, whereas equivalent numbers of KIT- cells or naive bone marrow cells do not. In these cultures, surface expression of Fc epsilon-RI is detected on a small number of cells by day 3 of culture with increased surface expression levels correlating roughly with metachromatic granule formation. The fact that Fc gamma-RIII and Fc epsilon-RI are not expressed on the cell surface of KIT+ lineage- cells but appear later in hematopoietic development makes it unlikely that these receptors influence early hematopoietic differentiation. The role that might justify such a complete surface expression of Fc gamma-RII by bone marrow progenitors remains to be identified.
Lantz
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CS
Department of Microbiology and Immunology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond 23298.
Huff
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TF
D000818:Animals; D001483:Base Sequence; D001854:Bone Marrow Cells; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D003594:Cytoplasmic Granules; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D016298:Hematopoietic Cell Growth Factors / Q000494:pharmacology; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D007377:Interleukin-3 / Q000494:pharmacology; D008407:Mast Cells / Q000166:cytology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D011518:Proto-Oncogene Proteins / Q000032:analysis*; D019009:Proto-Oncogene Proteins c-kit; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020794:Receptor Protein-Tyrosine Kinases / Q000032:analysis*; D016184:Receptors, Colony-Stimulating Factor / Q000032:analysis*; D017455:Receptors, IgE / Q000096:biosynthesis* / Q000235:genetics; D017452:Receptors, IgG / Q000096:biosynthesis* / Q000235:genetics; D019089:Stem Cell Factor
D016298:Hematopoietic Cell Growth Factors; D007377:Interleukin-3; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D016184:Receptors, Colony-Stimulating Factor; D017455:Receptors, IgE; D017452:Receptors, IgG; D019089:Stem Cell Factor; D019009:Proto-Oncogene Proteins c-kit; D020794:Receptor Protein-Tyrosine Kinases