Phenotypic and functional analysis of B lymphopoiesis in interleukin-7-transgenic mice: expansion of pro/pre-B cell number and persistence of B lymphocyte development in lymph nodes and spleen.
Transgenic mice in which mouse interleukin (IL)-7 cDNA is expressed under the control of the mouse major histocompatibility complex (MHC) class II (E alpha) promoter develop a lymphoproliferative disease characterized by the early polyclonal expansion of T cells followed in many cases by the development of lymphomas of immature B cells. Here, we have analyzed B cell development in these transgenic mice. Phenotypic analysis using monoclonal antibodies to B220, IgM, IgD, c-kit, IL-7 receptor, MHC class II, AA4.1, CD19, CD23, CD25, CD40 and CD43 shows that B lymphopoiesis in the bone marrow is dramatically altered and the number of pro/pre-B and immature B cells is significantly increased. Interestingly, pro/pre-B and immature B cells persist in the spleens of adult transgenic mice and are also present in lymph nodes and blood. Cell cycle analysis of lymph node cells shows that subpopulations of developing B cells retain the cell cycle profiles of their bone marrow counterparts. Limiting dilution analysis shows that the number of clonable pre-B cells is significantly increased and that at limiting dilution, growth of transgenic pre-B cells is still dependent on exogenous IL-7. Using semiquantitative polymerase chain reaction (PCR) and in situ hybridization, the level of IL-7 transcripts in the spleen was found to decrease between 2 and 4 weeks in control mice with levels in transgenics mice being approximately 50 times greater. These transgenic mice represent an interesting model with which to study the effects of IL-7 overexpression in the bone marrow and raise interesting questions regarding the regulation of B lymphopoiesis in normal mice.
Mertsching
E
E
U 184 INSERM, LGME CNRS, Faculté de Médecine, Strasbourg, France.
Grawunder
U
U
Meyer
V
V
Rolink
T
T
Ceredig
R
R
D000818:Animals; D016175:B-Lymphocyte Subsets / Q000145:classification / Q000276:immunology*; D001483:Base Sequence; D001853:Bone Marrow / Q000276:immunology; D002478:Cells, Cultured; D002999:Clone Cells / Q000276:immunology; D006410:Hematopoiesis / Q000276:immunology*; D006412:Hematopoietic Stem Cells / Q000276:immunology*; D016130:Immunophenotyping; D015851:Interleukin-7 / Q000032:analysis / Q000235:genetics*; D008198:Lymph Nodes / Q000276:immunology; D018655:Lymphocyte Count; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D014066:Palatine Tonsil / Q000166:cytology / Q000276:immunology*; D013154:Spleen / Q000166:cytology / Q000276:immunology*; D014158:Transcription, Genetic
D015851:Interleukin-7