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Macrophages control the retention and trafficking of B lymphocytes in the splenic marginal zone.

Karlsson MC, Guinamard R, Bolland S, Sankala M, Steinman RM, Ravetch JV - J. Exp. Med. (2003)

Bottom Line: Activation or disruption of this interaction results in MZB migration to the follicle.The migration of the MZMOs was further studied after the response to Staphylococcus aureus, which induced MZMOs to move into the red pulp while MZBs migrated into the follicular zone.The marginal zone is therefore a dynamic structure in which retention and trafficking of B cells requires specific macrophage-B cell interactions.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Molecular Genetics and Immunology, The Rockefeller University, Box 98, 1230 York Avenue, New York, NY 10021, USA.

ABSTRACT
The marginal zone of the spleen is a precisely ordered region that contains specialized subsets of B lymphocytes and macrophages. Disruption of the negative signaling inositol phosphatase, SH2-containing inositol-5-phosphatase 1 (SHIP), results in the loss of marginal zone B cells (MZBs) with reorganization of marginal zone macrophages (MZMOs) to the red pulp of the spleen. This primary macrophage defect, as revealed by selectively depleting SHIP in myeloid cells shows that MZMOs are specifically required for the retention of MZBs. The MZMO phenotype was reverted in SHIP/Bruton's tyrosine kinase (Btk) double knockout mice, thus identifying the Btk activating pathway as an essential component being regulated by SHIP. Furthermore, we identified a direct interaction between the MARCO scavenger receptor on MZMOs and MZBs. Activation or disruption of this interaction results in MZB migration to the follicle. The migration of the MZMOs was further studied after the response to Staphylococcus aureus, which induced MZMOs to move into the red pulp while MZBs migrated into the follicular zone. The marginal zone is therefore a dynamic structure in which retention and trafficking of B cells requires specific macrophage-B cell interactions.

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SHIP-deficient mice lack MZBs and MZMOs are displaced to the red pulp. (a) FACS® profiles of single cell suspensions from the spleen of SHIP-heterozygous (SHIP+/−) and -deficient (SHIP−/−) mice. MZBs were measured as the CD19+, CRIhigh, and CD23low population. The numbers shown represent percent of CD19+ cells for the depicted gates as an average of five mice. Numbers for the follicular B cells are shown for comparison. (b) Representative immunohistochemical analysis of above listed mice. At least four serial sections from each mouse were stained for MOMA-1+ (blue, top) metallophilic macrophages or MARCO+ MZMOs (blue, bottom). Sections were also stained for B220 (brown) to show the positioning of the follicle. ×10.
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fig1: SHIP-deficient mice lack MZBs and MZMOs are displaced to the red pulp. (a) FACS® profiles of single cell suspensions from the spleen of SHIP-heterozygous (SHIP+/−) and -deficient (SHIP−/−) mice. MZBs were measured as the CD19+, CRIhigh, and CD23low population. The numbers shown represent percent of CD19+ cells for the depicted gates as an average of five mice. Numbers for the follicular B cells are shown for comparison. (b) Representative immunohistochemical analysis of above listed mice. At least four serial sections from each mouse were stained for MOMA-1+ (blue, top) metallophilic macrophages or MARCO+ MZMOs (blue, bottom). Sections were also stained for B220 (brown) to show the positioning of the follicle. ×10.

Mentions: Mice deficient in the inhibitory signaling molecule SHIP display pleiotropic defects in macrophages, NK cells, and lymphocytes (18, 22). A prominent feature of these mice is their splenomegaly resulting from dysregulation of myeloid proliferation. As seen in Fig. 1 , SHIP-deficient mice also display a specific defect in the organization of the splenic follicle with the loss of MZBs measured as the CD21high/CD23low population in FACS® and in sections as the B220+ cells localizing peripherally to the MOMA-1+ cells (Fig. 1, a and b). In the SHIP-deficient mice the MARCO+ MZMO cells are no longer organized within the marginal zone and adjacent to the MOMA-1 macrophages but are redistributed to the red pulp, whereas MOMA-1+ metallophils remain unaffected (Fig. 1 b). Because SHIP is expressed in most hematopoietic cells, including lymphoid and myeloid subsets, we determined if this marginal zone phenotype in SHIP-deficient mice was the result of primary macrophage dysregulation. A conditional disruption of SHIP was generated in which macrophages displayed an approximate >90% reduction in SHIP expression whereas B cell expression was reduced by <10% (Fig. 2 , a and b). This is consistent with the expression patterns of Cre recombinase, driven by the lysosyme promoter used (19). The mice developed a splenomegaly at ∼5 wk of age (Fig. 2 b), similar to that of complete SHIP deletion, thus implicating a primary macrophage defect as the cause for splenomegaly in SHIP−/− mice (18). In addition, the mice displayed essentially the same marginal zone phenotype with significantly reduced MZBs as defined by flow cytometry and reorganization of the MZMOs as observed by histological staining (Fig. 2 c). To confirm that the SHIP phenotype is B cell nonautonomous and that SHIP-deficient B cells can give rise to MZB populations when WT MZMOs are available, we produced BM chimeras using SHIP-deficient BM combined with WT BM and injected these cells into irradiated WT recipients. In the resulting chimeric mice the SHIP-deficient and WT BMs contributed equally to the MZB population (unpublished data).


Macrophages control the retention and trafficking of B lymphocytes in the splenic marginal zone.

Karlsson MC, Guinamard R, Bolland S, Sankala M, Steinman RM, Ravetch JV - J. Exp. Med. (2003)

SHIP-deficient mice lack MZBs and MZMOs are displaced to the red pulp. (a) FACS® profiles of single cell suspensions from the spleen of SHIP-heterozygous (SHIP+/−) and -deficient (SHIP−/−) mice. MZBs were measured as the CD19+, CRIhigh, and CD23low population. The numbers shown represent percent of CD19+ cells for the depicted gates as an average of five mice. Numbers for the follicular B cells are shown for comparison. (b) Representative immunohistochemical analysis of above listed mice. At least four serial sections from each mouse were stained for MOMA-1+ (blue, top) metallophilic macrophages or MARCO+ MZMOs (blue, bottom). Sections were also stained for B220 (brown) to show the positioning of the follicle. ×10.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2194070&req=5

fig1: SHIP-deficient mice lack MZBs and MZMOs are displaced to the red pulp. (a) FACS® profiles of single cell suspensions from the spleen of SHIP-heterozygous (SHIP+/−) and -deficient (SHIP−/−) mice. MZBs were measured as the CD19+, CRIhigh, and CD23low population. The numbers shown represent percent of CD19+ cells for the depicted gates as an average of five mice. Numbers for the follicular B cells are shown for comparison. (b) Representative immunohistochemical analysis of above listed mice. At least four serial sections from each mouse were stained for MOMA-1+ (blue, top) metallophilic macrophages or MARCO+ MZMOs (blue, bottom). Sections were also stained for B220 (brown) to show the positioning of the follicle. ×10.
Mentions: Mice deficient in the inhibitory signaling molecule SHIP display pleiotropic defects in macrophages, NK cells, and lymphocytes (18, 22). A prominent feature of these mice is their splenomegaly resulting from dysregulation of myeloid proliferation. As seen in Fig. 1 , SHIP-deficient mice also display a specific defect in the organization of the splenic follicle with the loss of MZBs measured as the CD21high/CD23low population in FACS® and in sections as the B220+ cells localizing peripherally to the MOMA-1+ cells (Fig. 1, a and b). In the SHIP-deficient mice the MARCO+ MZMO cells are no longer organized within the marginal zone and adjacent to the MOMA-1 macrophages but are redistributed to the red pulp, whereas MOMA-1+ metallophils remain unaffected (Fig. 1 b). Because SHIP is expressed in most hematopoietic cells, including lymphoid and myeloid subsets, we determined if this marginal zone phenotype in SHIP-deficient mice was the result of primary macrophage dysregulation. A conditional disruption of SHIP was generated in which macrophages displayed an approximate >90% reduction in SHIP expression whereas B cell expression was reduced by <10% (Fig. 2 , a and b). This is consistent with the expression patterns of Cre recombinase, driven by the lysosyme promoter used (19). The mice developed a splenomegaly at ∼5 wk of age (Fig. 2 b), similar to that of complete SHIP deletion, thus implicating a primary macrophage defect as the cause for splenomegaly in SHIP−/− mice (18). In addition, the mice displayed essentially the same marginal zone phenotype with significantly reduced MZBs as defined by flow cytometry and reorganization of the MZMOs as observed by histological staining (Fig. 2 c). To confirm that the SHIP phenotype is B cell nonautonomous and that SHIP-deficient B cells can give rise to MZB populations when WT MZMOs are available, we produced BM chimeras using SHIP-deficient BM combined with WT BM and injected these cells into irradiated WT recipients. In the resulting chimeric mice the SHIP-deficient and WT BMs contributed equally to the MZB population (unpublished data).

Bottom Line: Activation or disruption of this interaction results in MZB migration to the follicle.The migration of the MZMOs was further studied after the response to Staphylococcus aureus, which induced MZMOs to move into the red pulp while MZBs migrated into the follicular zone.The marginal zone is therefore a dynamic structure in which retention and trafficking of B cells requires specific macrophage-B cell interactions.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Molecular Genetics and Immunology, The Rockefeller University, Box 98, 1230 York Avenue, New York, NY 10021, USA.

ABSTRACT
The marginal zone of the spleen is a precisely ordered region that contains specialized subsets of B lymphocytes and macrophages. Disruption of the negative signaling inositol phosphatase, SH2-containing inositol-5-phosphatase 1 (SHIP), results in the loss of marginal zone B cells (MZBs) with reorganization of marginal zone macrophages (MZMOs) to the red pulp of the spleen. This primary macrophage defect, as revealed by selectively depleting SHIP in myeloid cells shows that MZMOs are specifically required for the retention of MZBs. The MZMO phenotype was reverted in SHIP/Bruton's tyrosine kinase (Btk) double knockout mice, thus identifying the Btk activating pathway as an essential component being regulated by SHIP. Furthermore, we identified a direct interaction between the MARCO scavenger receptor on MZMOs and MZBs. Activation or disruption of this interaction results in MZB migration to the follicle. The migration of the MZMOs was further studied after the response to Staphylococcus aureus, which induced MZMOs to move into the red pulp while MZBs migrated into the follicular zone. The marginal zone is therefore a dynamic structure in which retention and trafficking of B cells requires specific macrophage-B cell interactions.

Show MeSH
Related in: MedlinePlus