scholarly journals B lymphocytes express and lose syndecan at specific stages of differentiation.

1989 ◽  
Vol 1 (1) ◽  
pp. 27-35 ◽  
Author(s):  
R D Sanderson ◽  
P Lalor ◽  
M Bernfield

Lymphopoietic cells require interactions with bone marrow stroma for normal maturation and show changes in adhesion to matrix during their differentiation. Syndecan, a heparan sulfate-rich integral membrane proteoglycan, functions as a matrix receptor by binding cells to interstitial collagens, fibronectin, and thrombospondin. Therefore, we asked whether syndecan was present on the surface of lymphopoietic cells. In bone marrow, we find syndecan only on precursor B cells. Expression changes with pre-B cell maturation in the marrow and with B-lymphocyte differentiation to plasma cells in interstitial matrices. Syndecan on B cell precursors is more heterogeneous and slightly larger than on plasma cells. Syndecan 1) is lost immediately before maturation and release of B lymphocytes into the circulation, 2) is absent on circulating and peripheral B lymphocytes, and 3) is reexpressed upon their differentiation into immobilized plasma cells. Thus, syndecan is expressed only when and where B lymphocytes associate with extracellular matrix. These results indicate that B cells differentiating in vivo alter their matrix receptor expression and suggest a role for syndecan in B cell stage-specific adhesion.

Blood ◽  
2010 ◽  
Vol 115 (14) ◽  
pp. 2810-2817 ◽  
Author(s):  
Sonia Merluzzi ◽  
Barbara Frossi ◽  
Giorgia Gri ◽  
Serena Parusso ◽  
Claudio Tripodo ◽  
...  

Abstract The evidence of a tight spatial interaction between mast cells (MCs) and B lymphocytes in secondary lymphoid organs, along with the data regarding the abundance of MCs in several B-cell lymphoproliferative disorders prompted us to investigate whether MCs could affect the proliferation and differentiation of B cells. To this aim, we performed coculture assays using mouse splenic B cells and bone marrow–derived MCs. Both nonsensitized and activated MCs proved able to induce a significant inhibition of cell death and an increase in proliferation of naive B cells. Such proliferation was further enhanced in activated B cells. This effect relied on cell-cell contact and MC-derived interleukin-6 (IL-6). Activated MCs could regulate CD40 surface expression on unstimulated B cells and the interaction between CD40 with CD40 ligand (CD40L) on MCs, together with MC-derived cytokines, was involved in the differentiation of B cells into CD138+ plasma cells and in selective immunoglobulin A (IgA) secretion. These data were corroborated by in vivo evidence of infiltrating MCs in close contact with IgA-expressing plasma cells within inflamed tissues. In conclusion, we reported here a novel role for MCs in sustaining B-cell expansion and driving the development of IgA-oriented humoral immune responses.


Blood ◽  
1990 ◽  
Vol 75 (2) ◽  
pp. 458-461
Author(s):  
S Kobayashi ◽  
S Imajoh-Ohmi ◽  
M Nakamura ◽  
S Kanegasaki

Cytochrome b558, involved in superoxide generation in phagocytes, was found to be expressed on the cell surface of most normal peripheral B lymphocytes. The cytochrome was not found on the surface of peripheral T lymphocytes, natural killer cells, or peripheral lymphocytes derived from patients with X-linked chronic granulomatous disease. On stimulation, at least half of peripheral B lymphocytes could generate superoxide anion as detected by superoxide dismutase-sensitive nitroblue tetrazorium reduction. Cytochrome b558 was not present on the surface of pre-pre B cells or pre-B cells, but did appear at the early B-cell stage. It disappeared from the B-cell surface during terminal differentiation to plasma cells. The transient expression of the cytochrome in B-cell lineage may indicate that superoxide generation is important for the function of these cells at certain stages.


Blood ◽  
2002 ◽  
Vol 99 (8) ◽  
pp. 2760-2766 ◽  
Author(s):  
Christoph Schaniel ◽  
Marie Gottar ◽  
Eddy Roosnek ◽  
Fritz Melchers ◽  
Antonius G. Rolink

Abstract Self-renewal, pluripotency, and long-term reconstitution are defining characteristics of single hematopoietic stem cells.Pax5−/− precursor B cells apparently possess similar characteristics. Here, using serial transplantations, with in vitro recloning and growth of the bone marrow–homed donor cells occurring after all transplantations, we analyzed the extent of self-renewal and hematopoietic multipotency ofPax5−/− precursor B-cell clones. Moreover, telomere length and telomerase activity in these clones was analyzed at various time points. Thus far, 5 successive transplantations have been performed. Clones transplanted for the fifth time, which have proliferated for more than 150 cell divisions in vitro, still repopulate the bone marrow with precursor B cells and reconstitute these recipients with lymphoid and myeloid cells. During this extensive proliferation, Pax5−/− precursor B cells shorten their telomeres at 70 to 90 base pairs per division. Their telomerase activity remains at 3% of that of HEK293 cancer cells during all serial in vivo transplantations/in vitro expansions. Together, these data show thatPax5−/− precursor B-cell clones possess extensive in vivo self-renewal capacity, long-term reconstitution capacity, and hematopoietic multipotency, with their telomeres shortening at the normal rate.


Author(s):  
Valentyn Oksenych

B lymphocyte development includes two DNA recombination processes, the V(D)J recombination of immunoglobulin (Igh) gene variable region and class switching when the Igh constant regions are changed from IgM to IgG, IgA, or IgE. The V(D)J recombination is required for successful maturation of B cells from pro-B to pre-B to immature-B and then to mature B cells in the bone marrow. The CSR occurs outside the bone marrow when mature B cells migrate to peripheral lymphoid organs, such as spleen and lymph nodes. Both V(D)J recombination and CSR depend on an “open chromatin” state that makes DNA accessible to specific enzymes, recombination activating gene (RAG), and activation-induced cytidine deaminase (AID). Acetyltransferases GCN5 and PCAF possess redundant functions acetylating histone H3 lysine 9 (H3K9). Here, we generated by complex breeding a mouse model with B cells lacking both GCN5 and PCAF. We found that double-deficient mice possess low levels of mature B cells in the bone marrow and peripheral organs, accumulation of pro-B cells in bone marrow, and reduced CSR levels. We concluded that both GCN5 and PCAF are required for B cell development in vivo.


2004 ◽  
Vol 200 (4) ◽  
pp. 411-423 ◽  
Author(s):  
Joseph E. Labrie ◽  
Alex P. Sah ◽  
David M. Allman ◽  
Michael P. Cancro ◽  
Rachel M. Gerstein

During aging, adaptive immunity is severely compromised, due in part to decreased production of B lymphocytes and loss of immunoglobulin (Ig) diversity. However, the molecular mechanisms that underlie age-associated diminished B cell production remain unclear. Using in vivo labeling, we find that this reduction in marrow pre–B cells reflects increased attrition during passage from the pro–B to pre–B cell pool. Analyses of reciprocal bone marrow chimeras reveal that the magnitude and production rates of pre–B cells are controlled primarily by microenvironmental factors, rather than intrinsic events. To understand changes in pro–B cells that could diminish production of pre–B cells, we evaluated rag2 expression and V(D)J recombinase activity in pro–B cells at the single cell level. The percentage of pro–B cells that express rag2 is reduced in aged mice and is correlated with both a loss of V(D)J recombinase activity in pro–B cells and reduced numbers of pre–B cells. Reciprocal bone marrow chimeras revealed that the aged microenvironment also determines rag2 expression and recombinase activity in pro–B cells. Together, these observations suggest that extrinsic factors in the bone marrow that decline with age are largely responsible for less efficient V(D)J recombination in pro–B cells and diminished progression to the pre–B cell stage.


1993 ◽  
Vol 178 (3) ◽  
pp. 1091-1096 ◽  
Author(s):  
P Corradini ◽  
M Boccadoro ◽  
C Voena ◽  
A Pileri

Multiple myeloma is a B cell malignancy characterized by the expansion of plasma cells producing monoclonal immunoglobulins (Ig). It has been regarded as a tumor arising at the B, pre-B lymphocyte, or even stem cell level. Precursor cells are presumed to proliferate and differentiate giving rise to the plasma cell clonal expansion. Antigenic features and specific Ig gene rearrangement shared by B lymphocytes and myeloma cells have supported this hypothesis. However, the existence of such a precursor is based upon indirect evidence and is still an open question. During differentiation, B cells rearrange variable (V) regions of Ig heavy chain genes, providing a specific marker of clonality. Using an anchor polymerase chain reaction assay, these rearranged regions from five patients with multiple myeloma were cloned and sequenced. The switch of the Ig constant (C) region was used to define the B cell differentiation stage: V regions are linked to C mu genes in pre-B and B lymphocytes (pre-switch B cells), but to C gamma or C alpha in post-switch B lymphocytes and plasma cells (post-switch B cells). Analysis of bone marrow cells at diagnosis revealed the presence of pre-switch B cells bearing plasma cell V regions still joined to the C mu gene. These cells were not identified in peripheral blood, where tumor post-switch B cells were detected. These pre-switch B cells may be regarded as potential myeloma cell precursors.


2021 ◽  
Author(s):  
Valentyn Oksenych

B lymphocyte development includes two DNA recombination processes, the V(D)J recombina-tion of immunoglobulin (Igh) gene variable region and class switching when the Igh constant regions are changed from IgM to IgG, IgA, or IgE. The V(D)J recombination is required for suc-cessful maturation of B cells from pro-B to pre-B to immature-B and then to mature B cells in the bone marrow. The CSR occurs outside the bone marrow when mature B cells migrate to periph-eral lymphoid organs, such as spleen and lymph nodes. Both V(D)J recombination and CSR de-pend on an open chromatin state that makes DNA accessible to specific enzymes, recombina-tion activating gene (RAG), and activation-induced cytidine deaminase (AID). Acetyltransferases GCN5 and PCAF possess redundant functions acetylating histone H3 lysine 9 (H3K9). Here, we generated by complex breeding a mouse model with B cells lacking both GCN5 and PCAF. We found that double-deficient mice possess low levels of mature B cells in the bone marrow and peripheral organs, accumulation of pro-B cells in bone marrow, and reduced CSR levels. We concluded that both GCN5 and PCAF are required for B cell development in vivo.


2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Rayelle Itoua Maïga ◽  
Guillaume Bonnaure ◽  
Josiane Tremblay Rochette ◽  
Sonia Néron

B lymphocyte differentiation into long-lived plasma cells is the keystone event for the production of long-term protective antibodies. CD40-CD154 and CD27-CD70 interactions are involved in human B lymphocyte differentiation into CD38hiCD138+cells in vivo as well as in vitro. In this study, we have compared these interactions in their capacity to drive switched-memory B lymphocytes differentiation into CD38hiCD138+plasma cells. The targeted B lymphocytes were isolated from human peripheral blood, expanded for 19 days, and then submitted to CD70 or CD154 interactions for 14 days. The expanded B lymphocytes were constitutively expressing CD39, whereas CD31’s expression was noticed only following the in vitro differentiation step (day 5) and was exclusively present on the CD38hicell population. Furthermore, the generated CD38hiCD138+cells showed a higher proportion of CD31+cells than the CD38hiCD138-cells. Besides, analyses done with human blood and bone marrow plasma cells showed that in vivo and de novo generated CD38hiCD138+cells have a similar CD31 expression profile but are distinct according to their reduced CD39 expression level. Overall, we have evidences that in vitro generated plasma cells are heterogeneous and appear as CD39+precursors to the ones present in bone marrow niches.


Blood ◽  
1997 ◽  
Vol 90 (9) ◽  
pp. 3751-3759 ◽  
Author(s):  
Linda M. Pilarski ◽  
Agnieszka J. Szczepek ◽  
Andrew R. Belch

Abstract Although chemotherapy effectively reduces the plasma cell burden in multiple myeloma (MM), the disease recurs. MM includes circulating and bone marrow (BM) localized components. A large majority of circulating CD11b+ MM B cells (81%) express an IgH VDJ rearrangement identical to that of autologous BM plasma cells. Unlike plasma cells, these monoclonal circulating B cells exhibit dye and drug transport activity before and throughout chemotherapy. Drug resistance was measured as the ability to export the fluorescent dye Rhodamine123 (Rh123) or the drug adriamycin, using flow cytometry. The role of P-glycoprotein 170 (P-gp), the multidrug transporter, was defined by cyclosporin A (CsA)-sensitive dye export. Only 8% to 11% of BM-localized plasma cells exported dye with the majority retaining dye, identified as bright staining. Circulating leukemic plasma cells were also unable to export dye and remained Rh123bright. However, 53% of circulating clonotypic MM B cells exhibited CsA-sensitive dye export. BM plasma cells taken before or after initiation of first line chemotherapy were equally unable to export dye. Thus in myeloma, differentiation to the plasma cell stage is accompanied by a loss of P-gp function, although P-gp phenotypic expression is retained. In contrast, for monoclonal gammopathy of undetermined significance (MGUS), 54% of BM-localized plasma cells exported dye, comparable to the 53% of circulating MGUS B cells that also exported dye, suggesting that the apparent defect in P-gp function is unique to myeloma plasma cells. Virtually all BM plasma cells in MM retained the drug adriamycin, consistent with their initial drug sensitivity in vivo, in contrast to circulating MM B cells, or to T cells in BM or blood. Thus, circulating B cells appear to be the predominant drug resistant component of the MM B-lineage hierarchy. This report suggests that successful therapeutic strategies will be those that target circulating B cells. Chemosensitization methods involving inhibition of P-gp are likely to improve depletion of these cells by compromising their ability to exclude drug. This work suggests that circulating clonotypic B cells should be monitored in clinical trials to confirm their depletion and the overall efficacy of novel treatment strategies.


Blood ◽  
1990 ◽  
Vol 75 (2) ◽  
pp. 458-461 ◽  
Author(s):  
S Kobayashi ◽  
S Imajoh-Ohmi ◽  
M Nakamura ◽  
S Kanegasaki

Abstract Cytochrome b558, involved in superoxide generation in phagocytes, was found to be expressed on the cell surface of most normal peripheral B lymphocytes. The cytochrome was not found on the surface of peripheral T lymphocytes, natural killer cells, or peripheral lymphocytes derived from patients with X-linked chronic granulomatous disease. On stimulation, at least half of peripheral B lymphocytes could generate superoxide anion as detected by superoxide dismutase-sensitive nitroblue tetrazorium reduction. Cytochrome b558 was not present on the surface of pre-pre B cells or pre-B cells, but did appear at the early B-cell stage. It disappeared from the B-cell surface during terminal differentiation to plasma cells. The transient expression of the cytochrome in B-cell lineage may indicate that superoxide generation is important for the function of these cells at certain stages.


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