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B cell development in the spleen takes place in discrete steps and is determined by the quality of B cell receptor-derived signals.

Loder F, Mutschler B, Ray RJ, Paige CJ, Sideras P, Torres R, Lamers MC, Carsetti R - J. Exp. Med. (1999)

Bottom Line: They develop into the transitional B cells of type 2 (T2), which are cycling and found exclusively in the primary follicles of the spleen.Mice with genetic deletions of elements participating in the B cell receptor signaling cascade display developmental arrest at the T1 or T2 stage.The analysis of these defects showed that the development of T2 and mature B cells from T1 precursors requires defined qualitative and quantitative signals derived from the B cell receptor and that the induction of longevity and maturation requires different signals.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Immunology, University of Freiburg, Germany.

ABSTRACT
Only mature B lymphocytes can enter the lymphoid follicles of spleen and lymph nodes and thus efficiently participate in the immune response. Mature, long-lived B lymphocytes derive from short-lived precursors generated in the bone marrow. We show that selection into the mature pool is an active process and takes place in the spleen. Two populations of splenic B cells were identified as precursors for mature B cells. Transitional B cells of type 1 (T1) are recent immigrants from the bone marrow. They develop into the transitional B cells of type 2 (T2), which are cycling and found exclusively in the primary follicles of the spleen. Mature B cells can be generated from T1 or T2 B cells. Mice with genetic deletions of elements participating in the B cell receptor signaling cascade display developmental arrest at the T1 or T2 stage. The analysis of these defects showed that the development of T2 and mature B cells from T1 precursors requires defined qualitative and quantitative signals derived from the B cell receptor and that the induction of longevity and maturation requires different signals.

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B cell development is blocked at the T2 stage in CD45−/− and CBA/N mice, but the number and the phenotype of MZ B cells is normal. Flow cytometric analysis of splenic B cells from normal C57BL/6 (control) and CD45−/− and CBA/N mice. (A) Cells were stained with Abs to IgM and IgD. T1, T2, and mature (M) B cells are boxed. (B) Cells were stained with Abs to CD23, CD21, and IgM and separated into CD23− and CD23+ cells. T1, T2, MZ, and mature B cells were identified as in Fig. 1 C. The fraction of T2 B cells represented 23% of all B cells in the normal mouse spleen, 55% in the CD45−/− spleen, and 50% in the CBA/N spleen.
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Figure 5: B cell development is blocked at the T2 stage in CD45−/− and CBA/N mice, but the number and the phenotype of MZ B cells is normal. Flow cytometric analysis of splenic B cells from normal C57BL/6 (control) and CD45−/− and CBA/N mice. (A) Cells were stained with Abs to IgM and IgD. T1, T2, and mature (M) B cells are boxed. (B) Cells were stained with Abs to CD23, CD21, and IgM and separated into CD23− and CD23+ cells. T1, T2, MZ, and mature B cells were identified as in Fig. 1 C. The fraction of T2 B cells represented 23% of all B cells in the normal mouse spleen, 55% in the CD45−/− spleen, and 50% in the CBA/N spleen.

Mentions: Development of mature B cells is compromised in mice deficient for CD45 and in mice mutant for Btk (CBA/N). We stained splenocytes of normal control, CD45−/−, and CBA/N mice with Abs to IgM, IgD, CD21, and CD23. Most of the splenic B cells of CD45−/− and CBA/N mice are phenotypically identical to the T2 B cells of normal mice. They are IgMbright IgDbright (Fig. 5 A, gate T2) and CD23+CD21bright (Fig. 5 B, bottom panels). T2 B cells, however, are present in a higher percentage: in CD45−/− mice, they represent 49% and in CBA/N mice 44% of all B cells, as compared with 15–20% in normal mice. The fraction of T1 B cells is only slightly reduced in size in CD45−/− mice and is normal in CBA/N mice.


B cell development in the spleen takes place in discrete steps and is determined by the quality of B cell receptor-derived signals.

Loder F, Mutschler B, Ray RJ, Paige CJ, Sideras P, Torres R, Lamers MC, Carsetti R - J. Exp. Med. (1999)

B cell development is blocked at the T2 stage in CD45−/− and CBA/N mice, but the number and the phenotype of MZ B cells is normal. Flow cytometric analysis of splenic B cells from normal C57BL/6 (control) and CD45−/− and CBA/N mice. (A) Cells were stained with Abs to IgM and IgD. T1, T2, and mature (M) B cells are boxed. (B) Cells were stained with Abs to CD23, CD21, and IgM and separated into CD23− and CD23+ cells. T1, T2, MZ, and mature B cells were identified as in Fig. 1 C. The fraction of T2 B cells represented 23% of all B cells in the normal mouse spleen, 55% in the CD45−/− spleen, and 50% in the CBA/N spleen.
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Related In: Results  -  Collection

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Figure 5: B cell development is blocked at the T2 stage in CD45−/− and CBA/N mice, but the number and the phenotype of MZ B cells is normal. Flow cytometric analysis of splenic B cells from normal C57BL/6 (control) and CD45−/− and CBA/N mice. (A) Cells were stained with Abs to IgM and IgD. T1, T2, and mature (M) B cells are boxed. (B) Cells were stained with Abs to CD23, CD21, and IgM and separated into CD23− and CD23+ cells. T1, T2, MZ, and mature B cells were identified as in Fig. 1 C. The fraction of T2 B cells represented 23% of all B cells in the normal mouse spleen, 55% in the CD45−/− spleen, and 50% in the CBA/N spleen.
Mentions: Development of mature B cells is compromised in mice deficient for CD45 and in mice mutant for Btk (CBA/N). We stained splenocytes of normal control, CD45−/−, and CBA/N mice with Abs to IgM, IgD, CD21, and CD23. Most of the splenic B cells of CD45−/− and CBA/N mice are phenotypically identical to the T2 B cells of normal mice. They are IgMbright IgDbright (Fig. 5 A, gate T2) and CD23+CD21bright (Fig. 5 B, bottom panels). T2 B cells, however, are present in a higher percentage: in CD45−/− mice, they represent 49% and in CBA/N mice 44% of all B cells, as compared with 15–20% in normal mice. The fraction of T1 B cells is only slightly reduced in size in CD45−/− mice and is normal in CBA/N mice.

Bottom Line: They develop into the transitional B cells of type 2 (T2), which are cycling and found exclusively in the primary follicles of the spleen.Mice with genetic deletions of elements participating in the B cell receptor signaling cascade display developmental arrest at the T1 or T2 stage.The analysis of these defects showed that the development of T2 and mature B cells from T1 precursors requires defined qualitative and quantitative signals derived from the B cell receptor and that the induction of longevity and maturation requires different signals.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Immunology, University of Freiburg, Germany.

ABSTRACT
Only mature B lymphocytes can enter the lymphoid follicles of spleen and lymph nodes and thus efficiently participate in the immune response. Mature, long-lived B lymphocytes derive from short-lived precursors generated in the bone marrow. We show that selection into the mature pool is an active process and takes place in the spleen. Two populations of splenic B cells were identified as precursors for mature B cells. Transitional B cells of type 1 (T1) are recent immigrants from the bone marrow. They develop into the transitional B cells of type 2 (T2), which are cycling and found exclusively in the primary follicles of the spleen. Mature B cells can be generated from T1 or T2 B cells. Mice with genetic deletions of elements participating in the B cell receptor signaling cascade display developmental arrest at the T1 or T2 stage. The analysis of these defects showed that the development of T2 and mature B cells from T1 precursors requires defined qualitative and quantitative signals derived from the B cell receptor and that the induction of longevity and maturation requires different signals.

Show MeSH
Related in: MedlinePlus