CCL19 Induced Responses Are Differentially Regulated by Atypical Chemokine Receptor CRAM and Its Classical Chemokine Receptor CCR7 in B-CLL Cells

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4896-4896 ◽  
Author(s):  
Nathalie Burger ◽  
Andrea Haerzschel ◽  
Marion Leick ◽  
Tanja Nicole Hartmann ◽  
Julie Catusse ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Chemokine Receptor ◽  
Chemokine Receptors ◽  
Conflicts Of Interest ◽  
Maturation Stage ◽  
Lymphoid Tissues ◽  
Dependent Manner ◽  
Chemokine Ligand ◽  
Cell Layers

Abstract Abstract 4896 Introduction: Chemokines are known to play an important role in the migration and survival of B-CLL cells. The non-signalling chemokine receptors, including DARC, D6 and CCX-CKR, have recently been shown to be involved in chemokine clearance and activity regulation. The human chemokine receptor CRAM is the most recently identified member of this atypical group. CRAM is expressed on B cells in a maturation-stage dependent manner, and to variable degrees on B-CLL cells. We have recently shown that it competitively binds CCL19 and that this binding is not followed by classical chemokine responses. CCL19 and its signalling receptor CCR7 are centrally involved in B cell localisation and maturation within the secondary lymphoid tissues. CCR7 is also highly expressed on B cells from CLL patients and mediates migration towards its ligands CCL19 and CCL21 which have been shown to be present at higher concentrations in serum of patients with lymphadenopathia compared to patients without. In this study we investigate the influence of CRAM on the CCL19 dependent responses of B-CLL cells and potential correlations to clinical data with a specific focus on lymphadenopathia. Results: We demonstrate that B cells from patients with B-CLL present high, but variable degrees of CCR7 and CRAM expression. Patients with compared to patients without lymphadenopathia show a higher CRAM expression level whereas the CCR7 expression is not significantly different. In single samples showing extremly high CRAM expression the migration towards CCL19 is reduced compared to patients with lower CRAM expression. These observations confirm results in the B-CLL cell line MEC-1 showing increased migration toward CCL19 when CRAM expression is reduced using CRAM-siRNA. On the other hand, CRAM seems to be a chemokine presenter as we can show that it does not degrade its chemokine ligand but presents it on the surface of polarised cell layers. Thus, we assume that CRAM plays a role for cell migration, possibly transmigration and cell localisation within lymph nodes of B-CLL cells. Conclusions: We show that CRAM can act as an integrator of different recruitment and activation factors. It is associated to CCR7 driven recruitment of B cells by regulating CCL19 availability. Expression of CRAM differs in B cell malignancies for which CCL19 and CCL21 have already been shown to be implicated in lymphadenopathia. We therefore suggest that CRAM is an additional player in the localisation and differentiation/maturation processes of malignant B cells of B-CLL patients. Disclosures: No relevant conflicts of interest to declare.

The Atypical Chemokine Receptor CRAM Mediates CCL19 Transcytosis through Endothelial Cells and Modulates CCL19 Activation of Non-Hodgkin Lymphoma B Cells.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2672-2672
Author(s):  
Marion Leick ◽  
Julie Catusse ◽  
Meike Burger
Keyword(s):  
Endothelial Cells ◽  
B Cells ◽  
B Cell ◽  
Chemokine Receptor ◽  
Chemokine Receptors ◽  
Receptor Expression ◽  
Dependent Manner ◽  
B Cell Malignancies ◽  
Cellular Recruitment

Abstract Abstract 2672 Poster Board II-648 Introduction: Chemokines work as cellular recruitment molecules. Specific combinations of chemokines, receptors, and adhesion molecules determine which subgroups of leukocytes migrate and what their destinations are. Chemokine receptor expression and activation on malignant cells may be involved in the growth, survival and migration of cancer cells as well as in the tumor vascularisation. CCR7, by binding the chemokines CCL19 and CCL21, is centrally involved in B cell localisation to the secondary lymphoid organs and therefore implicated in lymphadenopathy of various non-hodgkin lymphomas (NHL). In addition to chemokine receptors that have been cloned and described, various orphan receptors with a chemokine receptor-like structure are still not characterized. Atypical, non-signaling chemokine receptors are members of a newly described class of receptors and have been implicated with chemokine clearance and influencing of other signalling receptors. They are consequently considered as potent immuno-modulators and as anti-inflammatory factors and are implicated in progression of cancer. Among these receptors, we are investigating the role of the orphan chemokine (C-C motif) receptor-like 2 (CCRL2), also known as CRAM, a receptor expressed on endothelial cells and B cells in a maturation stage dependent manner, but for which functions and ligands are poorly characterized so far. In an effort to elucidate the role of CRAM and its implication in neoplasias, we have focussed research on identification of ligands and the implication of CRAM in regulating B cell migration in samples from healthy donors and from non-Hodgkin lymphomas. Methods: We characterised the receptor's expression profile by flow cytometry in peripheral blood, bone marrow and lymph node sections of different B cell NHL and correlated it to expression levels of CCR7 and CXCR4. In addition, a screening for ligands was performed using radiolabelled binding assays. The role of CRAM was elucidated using various functional assays, internalisation and transcytosis experiments. Results: We show that CRAM is an alternative, but non-signaling receptor for the CCR7-activating chemokine CCL19. CRAM is constitutively recycling to and from the cell surface and internalizing the chemokine without degrading it. We found that the receptor is responsible for transcytosis of CCL19 through endothelial cell layers and subsequent presentation, a crucial step in homing of leukocytes to the lymph nodes. On the other hand, when expressed on B cells, CRAM interferes in CCL19 binding to CCR7. We thereby show that CRAM can act as an integrator of different signals, by binding different chemokines and controlling their activity toward surrounding ligands. Chemotaxis experiments demonstrate that CRAM is a negative modulator of CCL19 B cell recruitment. In addition, we have found increased expression in activated B cells, dendritic cells, and also in the B cell malignancies chronic lymphocytic leukemia (B-CLL) and pre-B cell acute lymphoblastic leukemia (pre-B ALL), and are currently evaluating CRAM as a possible prognostic marker in various B-NHLs. Conclusions: CRAM is a newly identified member of the silent or atypical chemokine receptor group, already known for modulating chemokine availability, together with D6, DARC and CCX-CKR. We have shown here that it contributes to lymphocyte recruitment into peripheral lymphoid tissue by presenting CCL19 on endothelium. It is also involved in CCR7 driven recruitment of B cells by regulating CCL19 availability. Expression of CRAM differs in B cell malignancies for which both CCR7 ligands, CCL19 and CCL21, have already been shown to be implicated in the development of lymphadenopathies. We therefore suggest that CRAM is an additional player and potential biomarker in determining outcome and development of disease. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Developmental Switches in Chemokine Response Profiles during B Cell Differentiation and Maturation

2000 ◽  
Vol 191 (8) ◽  
pp. 1303-1318 ◽  
Author(s):  
Edward P. Bowman ◽  
James J. Campbell ◽  
Dulce Soler ◽  
Zengjun Dong ◽  
Natasha Manlongat ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
B Cells ◽  
B Cell ◽  
Chemokine Receptor ◽  
Chemokine Receptors ◽  
Cell Subset ◽  
Lymphoid Tissues ◽  
B Cell Differentiation ◽  
Interleukin 7 ◽  
Developmental Switches

Developing B cells undergo dramatic changes in their responses to chemoattractant cytokines (chemokines) and in expression of chemokine receptors. Bone marrow pre–pro-B cells (AA4.1+/natural killer 1.1− Fraction A cells) and cells capable of generating pro-B colonies in the presence of interleukin 7 and flt3 ligand migrate to thymus-expressed chemokine (TECK), a response lost in later stages of B cell development. B cell–attracting chemokine 1 (BCA-1) responses correlate with CXC chemokine receptor (CXCR)5 expression, are first displayed by a pro-B cell subset, are lost in pre-B cells, and then are regained just before and after egress from the marrow. All peripheral B cell subsets, including follicular and germinal center as well as marginal zone and peritoneal B1 B cells, respond to BCA-1, implying that responsiveness to this follicular chemokine is not sufficient to predict follicle localization. Responses to the CC chemokine receptor (CCR)7 ligands secondary lymphoid tissue chemoattractant (SLC) and macrophage inflammatory protein (MIP)-3β, implicated in homing to lymphoid tissues, are upregulated before B cell exit from the marrow, but increase further in the periphery and are shared by all peripheral B cells. In contrast, responsiveness to MIP-3α and expression of CCR6 are acquired only after emigration to the periphery and during maturation into the recirculating B cell pool. Chemotaxis to stromal cell–derived factor 1α is observed at all stages of B cell differentiation. Thus, unique patterns of chemokine responses may help define developing B cell populations and direct their maturation in the marrow and migration to the periphery.

Abstract 464: Chemokine Receptor CCR6 Expression on B Cells Augments Local IgM Production and Atheroprotection

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Prasad Srikakulapu ◽  
Chantel McSkimming ◽  
Coleen McNamara
Keyword(s):  
B Cells ◽  
B Cell ◽  
Adoptive Transfer ◽  
Chemokine Receptors ◽  
Immune Cell ◽  
Dependent Manner ◽  
Perivascular Adipose Tissue ◽  
Cell Recruitment ◽  
Cell Numbers ◽  
Atherosclerosis Development

Background: CCR6 mediates immune cell recruitment to inflammatory sites and has cell type-specific effects on diet-induced atherosclerosis in mice. Recent studies implicate the local immune responses in the adventitia/perivascular adipose tissue (PVAT) in atherosclerosis development. We have previously demonstrated that adoptive transfer of CD43 - splenocytes (B cells) into B cell deficient μMT -/- ApoE -/- mice results in reduced diet-induced atherosclerosis in a CCR6-dependent manner. Notably, there were significantly greater numbers of B cells in the aorta including PVAT of μMT -/- ApoE -/- mice which received splenic B cells from CCR6 +/+ mice compared to CCR6 -/- mice, despite no difference in B cell numbers in blood, spleen and peritoneal cavity, suggesting that CCR6 expression on B cells is important in B cell aortic homing. Production of IgM antibodies is thought to be a major mechanism whereby B cells limit atherosclerosis development. Yet whether B cells produce IgM locally in the PVAT and whether this is regulated by chemokine receptors such as CCR6 is unknown. Methods and Results: FACS experiments demonstrated high numbers of B cells available in the PVAT than aorta of young ApoE -/- (49121±11190 and 80±11; p<0.001, n=7) mice. ELISPOT experiments demonstrated significantly fewer IgM secreting cells were in the PVAT of ApoE -/- CCR6 -/- mice compared to ApoE -/- CCR6 +/+ mice (100±25 vs 850±150, p<0.05, n=5), despite no differences in IgM secreting cell numbers in spleen and bone marrow. Adoptive transfer of CD43 - splenic B cells from ApoE -/- CCR6 -/- and ApoE -/- CCR6 +/+ mice into secretory IgM deficient ApoE -/- sIgM -/- mice demonstrated significantly reduced atherosclerosis in mice that received B cells from ApoE -/- CCR6 +/+ mice compared to those that received B cells from ApoE -/- CCR6 -/- mice. Moreover, the B cells from ApoE -/- CCR6 +/+ mice attenuated atherosclerosis only when they were capable of secreting IgM. FACS data from human blood demonstrated that circulating B and T cells but not monocytes express CCR6, suggesting potential human relevance to our murine findings. Conclusion: Results provide evidence that CCR6 expression on B cells mediates B cell recruitment into aorta and/or PVAT to provide atheroprotection via IgM secretion.

Role Of Lyn Kinase In The Pathogenesis Of Chronic Lymphocytic Leukemia

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 668-668
Author(s):  
Phuong-Hien Nguyen ◽  
Nina Reinart ◽  
Michael Hallek
Keyword(s):  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Conflicts Of Interest ◽  
Myeloid Cells ◽  
Lymphocytic Leukemia ◽  
Negative Regulator ◽  
Lymphoid Tissues ◽  
Malignant Cells ◽  
Deficient Mice

Abstract The Src family kinase Lyn is predominantly expressed in B cells and plays a central role in initiating B cell receptor (BCR) signaling. Lyn is associated with BCR complexes and is renowned for its role in B cell activation and proliferation. Active Lyn contributes to positive regulation of signalling through tyrosine phosphorylation of components of the BCR. Intriguingly, Lyn was also shown as a negative regulator of BCR signal transduction. Lyn plays an essential role in negative regulation of signalling through its unique ability to phosphorylate immunoreceptor tyrosine based inhibition motifs (ITIM) in inhibitory cell surface receptors. ITIM phosphorylation induces the recruitment of inhibitory phosphatases such as SHP-1/2 and SHIP-1, which attenuate BCR signalling. Lyn-deficient mice have reduced number of B cells and increased numbers of myeloid progenitors. It was reported that expression and activity of Lyn in human chronic lymphocytic leukemia (CLL) is elevated compared to healthy B cells. Besides, higher levels of Lyn are associated with a shorter treatment-free survival of CLL patients. This rises up a hypothesis about Lyn’s significant role in B cell tumorigenesis, malignant transformation of B cells, and the balance between myeloid cells and B lymphocytes. We generated Eµ-TCL1 transgenic LYN-deficient mice (TCL1+/wtLYN-/-) and monitored them in order to identify the population of malignant B cells and to characterize the development of malignant cells in these mice in comparison with Eµ-TCL1 transgenic mice (TCL1+/wtLYNwt/wt). In comparison to TCL1+/wtLYNwt/wt mice, TCL1+/wtLYN-/- mice show a significantly reduced number of malignant B cells in the peripheral blood, as well as a reduced leukocyte count. Besides, TCL1+/wtLYN-/- mice have significantly decreased infiltration of malignant B cells in lymphoid tissues such as spleen, liver, lymph node and bone marrow. This result is also resembled in a hepato-splenomegaly in the TCL1+/wtLYNwt/wt mice. These mice develop severe splenomegaly and hepatomegaly due to infiltration of malignant cells, while TCL1+/wtLYN-/- mice do not develop hepatomegaly. The non-transgenic LYN-/- control mice develop splenomegaly due to infiltration of myeloid cells. Although TCL1+/wtLYN-/- mice have hindered development of TCL1-induced CLL, preliminary data suggest it is not only due to LYN-deficiency in B cell compartment of these mice. Indeed, B cell of TCL1+/wtLYN-/- mice show enhanced proliferation and better survival ex vivo compared to TCL1+/wtLYNwt/wt mice. Notably, TCL1+/wtLYN-/- mice developed a skewed microenvironment which might contribute to CLL down regulation. LYN-/- microenvironment, particularly in aged mice, does not support engraftment of TCL1-induced leukemic B cell as well as LYNwt/wt mice in our transplantation model. These results point to a complex regulation of Lyn signalling in CLL involving not only leukemic cells but also cells of the micromillieu, that needs further investigation. Disclosures: No relevant conflicts of interest to declare.

The Chemokine Receptor Profile As Distinctive Criterion Between Normal B-Cell Subsets and As Potential Discriminative Marker to Identify the Cell of Origin in Patients with Chronic Lymphocytic Leukemia and Richter Syndrome

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3890-3890
Author(s):  
Katharina Troppan ◽  
Kerstin Wenzl ◽  
Peter Neumeister ◽  
Christine Beham-Schmid ◽  
Martina Przekopowitz ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Chemokine Receptor ◽  
Chemokine Receptors ◽  
De Novo ◽  
Memory B Cells ◽  
Cell Of Origin ◽  
Richter Syndrome ◽  
Receptor Profile ◽  
B Cell Subsets

Abstract Chemokine receptors are G-protein-coupled cell surface receptors, which dissociate upon activation by their ligands and cause downstream signaling. Several studies have revealed the crucial contribution of chemokine receptors and their ligands in normal B-cell differentiation and development of hematopoietic malignancies. The Richter syndrome (RS) represents the clinico-pathologic transformation of chronic lymphocytic leukaemia (CLL) to an aggressive lymphoma, most commonly diffuse large B-cell lymphoma (DLBCL). Due to the lack of knowledge on the chemokine receptor, we aimed to investigate their expression profile in patients with CLL and Richter syndrome. Therefore, we investigated the mRNA expression levels of 18 known chemokine receptors (CCR1-CCR9, CXCR1-CXCR7, XCR1, CX3CR1) by using semi-quantitative real-time PCR on seven samples of paired (CLL and transformed DLBCL) RS samples, additionally four CLL samples -all of them subsequently transformed into DLBCL-, and eight transformed DLBCL samples originating from CLL. Additionally, 30 samples of de-novo DLBCL, including 10 germinal center B-cell (GCB) lymphomas, 12 non-germinal center B-cell lymphomas (non-GCB), and 8 unclassified DLBCL were included. Four samples of naïve B-cells (CD5 neg), CD5+ naïve B-cells and CD27+ memory B-cells (n=12) served as non-neoplastic controls. No differences in the chemokine receptor profile were detected between CD5+ and negative naïve B-cells. When comparing CD27+ memory B-cells to naïve B-cells a significant lower expression level was found for CCR7 (7-fold), CXCR4 (4-fold), and CXCR5 (1.5 fold). CCR7 (5-fold) and CXCR4 (5-fold) were also lower expressed in CD27+ memory B-cells compared to CD5+ naïve B-cells. Five out of 18 chemokine receptors were differentially expressed comparing the distinct normal B-cell subsets with RS samples. Comparing CLL samples and RS samples to CD5+ naïve B-cells, CXCR4 (12-fold for CLLs and 10-fold for RS samples) and CXCR5 (2-fold for CLLs and 2.4-fold for RS samples) were lower expressed, whereas CXCR3 (10-fold for CLLs and 8.5-fold for the transformed samples) was higher expressed and CCR5 de-novo expressed. Compared to naïve B-cells, the same chemokine receptors were deregulated: CXCR4 (10-fold for CLLs and 8.5-fold for the RS samples) and CXCR5 (2-fold for CLLs and 2.4-fold for the transformed samples) were lower expressed, CXCR3 (45-fold for CLLs and 30-fold for the transformed samples) was higher expressed and CCR5 was de-novo expressed. Comparing CLL samples and transformed RS samples to CD27+ memory B-cells, CCR5 (5.1-fold for CLLs and 4.3-fold for the RS samples) and CCR7 (8.7-fold for CLLs and 10-fold for the transformed samples) were higher expressed in both malignancies. Only one chemokine receptor was found to be differentially expressed in our seven paired RS samples: CCR6 showed a trend of a higher expression (1.4-fold) in CLL components. Considering RS and GCB DLBCL, CCR1, CCR5, and CXCR6 were found to be significantly down-regulated in RS (at least 4-fold), in contrast to CCR7 and CXCR4, which showed higher expression levels in RS (6-fold). CCR1 and CCR5 were lower expressed comparing RS and non-GCB DLBCL (25-fold and 8-fold), whereas CCR7 again, together with CXCR7, was higher expressed (3- fold and 6-fold respectively). Our data indicate a difference in the chemokine receptor profile within normal B-cell subsets. These differences are also reflected in the different expression profile of low and high aggressive component of CLL/RS compared to the distinct B cell subtypes. Hence, in future these multiple deregulated CC and CXC receptors might serve as a further hint in identifying the cell of origin of different B-cell malignancies. Disclosures No relevant conflicts of interest to declare.

SYK regulates B-cell migration by phosphorylation of the F-actin interacting protein SWAP-70

Blood ◽  
2011 ◽  
Vol 117 (5) ◽  
pp. 1574-1584 ◽  
Author(s):  
Glen Pearce ◽  
Tatsiana Audzevich ◽  
Rolf Jessberger
Keyword(s):  
Cell Migration ◽  
B Cells ◽  
B Cell ◽  
Cell Polarization ◽  
Actin Binding ◽  
Lymphoid Tissues ◽  
Dependent Manner ◽  
Interacting Protein

Abstract B-cell migration into and within lymphoid tissues is not only central to the humoral immune response but also for the development of malignancies and autoimmunity. We previously demonstrated that SWAP-70, an F-actin-binding, Rho GTPase-interacting protein strongly expressed in activated B cells, is necessary for normal B-cell migration in vivo. SWAP-70 regulates integrin-mediated adhesion and cell attachment. Here we show that upon B-cell activation, SWAP-70 is extensively posttranslationally modified and becomes tyrosine phosphorylated by SYK at position 517. This phosphorylation inhibits binding of SWAP-70 to F-actin. Phospho-site mutants of SWAP-70 disrupt B-cell polarization in a dominant-negative fashion in vitro and impair migration in vivo. After CXCL12 stimulation of B cells SYK becomes activated and SWAP-70 is phosphorylated in a SYK-dependent manner. Use of the highly specific SYK inhibitor BAY61-3606 showed SYK activity is necessary for normal chemotaxis and B-cell polarization in vitro and for entry of B cells into lymph nodes in vivo. These findings demonstrate a novel requirement for SYK in migration and polarization of naive recirculating B cells and show that SWAP-70 is an important target of SYK in this pathway.

scholarly journals A unique B2 B cell subset in the intestine

2008 ◽  
Vol 205 (6) ◽  
pp. 1343-1355 ◽  
Author(s):  
Yasuyo Shimomura ◽  
Atsuhiro Ogawa ◽  
Mayumi Kawada ◽  
Ken Sugimoto ◽  
Emiko Mizoguchi ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Intestinal Inflammation ◽  
Somatic Hypermutation ◽  
Alternative Pathway ◽  
Cell Subset ◽  
Immunoglobulin M ◽  
Lymphoid Tissues ◽  
Dependent Manner ◽  
Cell Pool

Over 80% of the body's activated B cells are located in mucosal sites, including the intestine. The intestine contains IgM+ B cells, but these cells have not been characterized phenotypically or in terms of their developmental origins. We describe a previously unidentified and unique subset of immunoglobulin M+ B cells that present with an AA4.1−CD21−CD23− major histocompatibility complex class IIbright surface phenotype and are characterized by a low frequency of somatic hypermutation and the potential ability to produce interleukin-12p70. This B cell subset resides within the normal mucosa of the large intestine and expands in response to inflammation. Some of these intestinal B cells originate from the AA4.1+ immature B2 cell pool in the steady state and are also recruited from the recirculating naive B cell pool in the context of intestinal inflammation. They develop in an antigen-independent and BAFF-dependent manner in the absence of T cell help. Expansion of these cells can be induced in the absence of the spleen and gut-associated lymphoid tissues. These results describe the existence of an alternative pathway of B cell maturation in the periphery that gives rise to a tissue-specific B cell subset.

Distinct Chemokine Receptor Profile In Chronic Lymphocytic Leukaemia and Richter Transformed Diffuse Large B Cell Lymphomas Compared To Germinal Center B Cells and De Novo Diffuse Large B Cell Lymphomas

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4852-4852
Author(s):  
Kerstin Wenzl ◽  
Katharina Troppan ◽  
Alexander JA Deutsch ◽  
Werner Linkesch ◽  
Peter Neumeister ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Chemokine Receptor ◽  
Germinal Center ◽  
Chemokine Receptors ◽  
Lymphocytic Leukaemia ◽  
De Novo ◽  
Richter Syndrome ◽  
Large B Cell ◽  
Germinal Center B Cells

Abstract Chemokine receptors are G-protein-coupled cell surface receptors, which dissociate upon activation by their ligands and cause downstream signaling. Recently, several studies have revealed the crucial contribution of chemokine receptors and their ligands in normal B-cell differentiation and development of hematopoietic malignancies. The Richter syndrome (RS) represents the clinico-pathologic transformation of chronic lymphocytic leukaemia (CLL) to an aggressive lymphoma, most commonly diffuse large B-cell lymphoma (DLBCL). Due to the lack of knowledge on the chemokine receptors in RS, we aimed to investigate their expression profile in Richter syndrome patients. Therefore, we investigated the mRNA expression levels of 18 known chemokine receptors (CCR1-CCR9, CXCR1-CXCR7, XCR1, CX3CR1) by using semi-quantitative real time PCR on seven samples of paired (CLL and transformed DLBCL) RS samples, and six samples of de novo DLBCL, additionally four CLL samples –all of them transformed into DLBCL-, and eight transformed DLBCL samples –all of them originated from CLL- were included. Four samples of peripheral B cells and four samples of germinal center B cells (GCB) served as non-neoplastic controls. 11 out of 18 chemokine receptors were differentially expressed in CLL (RL) and transformed DLBCL originated from CLL (RH) compared to GCBs. RL exhibited an at least 15-fold higher expression of CCR2, CCR4, CCR7, CXCR3, and XCR1, as well as a de novo expression of CCR3, CCR8, CXCR1, CXCR2, and CX3CR1 compared to GCB. Additionally to these chemokine receptors, CCR1 also showed significant higher expression levels comparing GCB and RH samples. Only one chemokine receptor was found to be differentially expressed in our seven paired RS samples: CCR6 showed a trend of up-regulation in CLL components. Interestingly, the transformed DLBCL originated from CLL were characterized by a significant up-regulation of six chemokine receptors (CCR3, CCR7, CXCR1, CXCR3, CXCR4, and CX3CR1) and a down-regulation of CCR5 compared to DLBCL. Our data indicate that the chemokine receptor expression profile of CLL and transformed DLBCL, originated from CLL samples, differs substantially from those of non neoplastic germinal center B cells and de novo DLBCL, suggesting other cellular origin and an impact on more aggressive clinical course of Richter syndrome patients. Hence, these multiple deregulated CC and CXC receptor might serve as useful prognostic tool to separate high malignant Richter syndrome from de novo DLBCL. Disclosures: No relevant conflicts of interest to declare.

A GM-CSF and IL-4 Fusion Cytokine Triggers Conversion of B-Cells to Tumoricidal Effectors

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1048-1048
Author(s):  
Jiusheng Deng ◽  
Pingxin Li ◽  
Andrea Pennati ◽  
Shala Yuan ◽  
Hsiang-Chuan (Jeremy) Hsieh ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Plasma Cells ◽  
Conflicts Of Interest ◽  
Dependent Manner ◽  
Gm Csf ◽  
Helper Function ◽  
Specific Effector ◽  
Homeostatic Expansion

Abstract Abstract 1048 We have previously demonstrated that coupling of GMCSF at the N-terminus of common γ-chain interleukins IL2, IL15 and IL21 leads to meaningful gain-of function activity in interleukin-responsive lymphomyeloid cells. Considering the physiological and immunological importance of IL4 that is a member of γ-chain interleukins, we tested the bioactivity of a novel fusion cytokine consisting of a fusion between GM-CSF and IL-4 (GIFT4). We observed that GIFT4 leads to a pan-STAT hyper-phosphorylation response in resting splenic B-cells distinct from IL4 only and that treated B-cells up-regulated expression of MHCI/II, CD80 and CD86, secreted IL-12, IL-1a, IL-6, and substantial amounts of CCL3 and GM-CSF, akin to recently described innate response activator (IRA) B-cells (Science 335, 597, 2012). In vivo delivery of recombinant GIFT4 protein to normal mice leads to homeostatic expansion of splenic B cells and plasma cells as well as humoral hyper-responsiveness to antigenic challenge. We further showed that B16F0 melanoma cells engineered to secrete GIFT4 are immune-rejected in a B-cell dependent manner. The clinical effect was abolished when B16F0-GIFT4 cells were implanted in B-cell deficient μMT, CD4−/−, CD8−/− or FcγR−/− mice consistent with a pivotal for B cells, their T-cell helper function and antibody-dependent cell-mediated cytotoxicity for the observed melanoma-specific therapeutic effect. Thus, GIFT4 defines a novel engineered cytokine that mediates endogenous expansion of B-cells with potent immune helper and antigen-specific effector function. We propose that GIFT4 protein could serve as a novel immunotherapeutic agent and defines a previously unrecognized potential of B-cells as tumoricidal effectors. Disclosures: No relevant conflicts of interest to declare.

Aid-Initiated DNA Lesions Are Differentially Processed in Distinct B Cell Differentiation Stages in a Locus-Dependent Manner.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2376-2376
Author(s):  
Zhangguo Chen ◽  
Sawanee Viboolsittiseri ◽  
Maxwell Eder ◽  
Shunzong Yuan ◽  
Jing H. Wang
Keyword(s):  
B Cells ◽  
B Cell ◽  
Conflicts Of Interest ◽  
Genetic Alterations ◽  
Dna Lesions ◽  
Dependent Manner ◽  
B Cell Differentiation ◽  
Activation Induced Deaminase ◽  
Differentiation Stage ◽  
Activated B Cells

Abstract Abstract 2376 Activation induced deaminase (AID) initiates U:G mismatches that are subsequently converted into point mutations or DNA double-stranded breaks. AID-mediated DNA alterations in switch (S) regions at the Igh locus frequently occur in both antigen-stimulated germinal center (GC) B cells and cytokine-activated B cells. To investigate whether AID-initiated U:G lesions are differentially processed in a differentiation stage-specific manner at non-Ig loci to maintain genome stability, we established a knock-in model by inserting an Sg2b region into the first intron of proto-oncogene c-myc. We found that the inserted Sg2b region mutated at an extremely low level and did not enhance genomic instability of c-myc locus in antigen-stimulated GC B cells. In contrast, the inserted Sg2b region mutated more frequently and increased c-myc locus abnormalities in cytokine-activated B cells. Furthermore, uracil glycosylase deficiency led to increased mutation frequency at the c-myc locus. These results reveal that AID-initiated lesions are differentially processed via error-free or error-prone repair in a differentiation stage-specific and locus-dependent manner. Our data might provide mechanistic explanation for differential frequency of AID-mediated genetic alterations in distinct subtypes of common B cell lymphomas. Disclosures: No relevant conflicts of interest to declare.

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