Identification of CD19–B220+c-Kit+Flt3/Flk-2+cells as early B lymphoid precursors before pre-B-I cells in juvenile mouse bone marrow

• Published in: International immunology 2000-03, Vol.12 (3), p.313-324
• Main Authors: Ogawa, Minetaro, Boekel, Edwin ten, Melchers, Fritz
• Format: Article
• Language: English
• Subjects: ACDU automatic cell deposition unit; Age Factors; Animals; Antigens, CD19 - analysis; Antigens, Differentiation, B-Lymphocyte - analysis; APC allophycocyanin; B-Lymphocytes - cytology; Cell Differentiation - drug effects; Coculture Techniques; Colony-Forming Units Assay; DHJH recombination; Dipeptidyl Peptidase 4 - biosynthesis; Dipeptidyl Peptidase 4 - genetics; Erythropoietin - pharmacology; FL Flt3/Flk-2 ligand; fms-Like Tyrosine Kinase 3; Gene Rearrangement, B-Lymphocyte, Heavy Chain; Hematopoietic Stem Cells - chemistry; Hematopoietic Stem Cells - cytology; Hematopoietic Stem Cells - drug effects; HSA heat-stable antigen; HSC hematopoietic stem cells; Humans; IL-7; Immunoglobulin Light Chains; Immunoglobulin Light Chains, Surrogate; Interleukin-7 - pharmacology; Leukocyte Common Antigens - analysis; Membrane Glycoproteins - biosynthesis; Membrane Glycoproteins - genetics; Membrane Proteins - pharmacology; Mice; Mice, Inbred C57BL; Mice, Transgenic; PE phycoerythrin; Proto-Oncogene Proteins - analysis; Proto-Oncogene Proteins c-kit - analysis; Receptor Protein-Tyrosine Kinases - analysis; receptor tyrosine kinase; Recombinant Fusion Proteins - biosynthesis; Recombinant Fusion Proteins - pharmacology; Reverse Transcriptase Polymerase Chain Reaction; SCF stem cell factor; Stem Cell Factor - pharmacology; Stromal Cells - cytology
• ISSN: 0953-8178; 1460-2377
• DOI: 10.1093/intimm/12.3.313

The combined analysis of the expression of receptor tyrosine kinases c-Kit and Flt3/Flk-2 and of the human CD25 gene expressed as a transgene under the regulation of the mouse λ5 promoter in the bone marrow of 1-week-old mice allows us to identify three stages of B lymphocyte development before the CD19+c-Kit+ pre-B-I cells. Single-cell PCR analysis of the rearrangement status of the Ig heavy chain alleles allows us to order these early stages of B cell development as follows: (i) B220+CD19–c-KitloFlt3/Flk-2hiλ5–, (ii) B220+CD19–c-KitloFlt3/Flk-2hiλ5+ and (iii) B220+CD19+c-KitloFlt3/Flk-2loλ5+ before B220+CD19+c-KitloFlt3/Flk-2–λ5+ pre-B-I cells. All these progenitors are clonable on stromal cells in the presence of IL-7 and can differentiate to CD19+c-Kit– B-lineage cells. A combination of stem cell factor, Flt3 ligand and IL-7 was also able to support the proliferation and differentiation of the progenitors in a suspension culture. Furthermore, the analyses indicate that the onset of DHJH rearrangements precedes the expression of the λ5 gene. These progenitor populations were characteristic of juvenile mice and could not be detected in the bone marrow of adult mice. Hence the expression pattern, and probably the function, of the receptor tyrosine kinases in early B cell differentiation appears to be different in juvenile and adult mice.