Frequent Loss of the SLP-65 Adapter Protein in Childhood Acute B-Precursor Lymphoblastic Leukemia (ALL) with TEL/AML1 Rearrangement.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 741-741 ◽  
Author(s):  
Arndt Borkhardt ◽  
Christine Damm-Welk ◽  
Thomas Wossning ◽  
Bettina Storch ◽  
Uta Fuchs ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
B Cells ◽  
Tumor Suppressor ◽  
Protein Expression ◽  
B Cell ◽  
Cell Lines ◽  
Sh2 Domain ◽  
B Cell Differentiation ◽  
Cell Leukemia ◽  
B Cell Leukemia

Abstract The adaptor protein SLP-65 plays an essential role during B cell differentiation. A crucial consequence of SLP-65 deficiency in mice is a high incidence of pre-B-cell leukemia, suggesting a tumor suppressor role for SLP-65 in pre-B-cells. While the link between SLP-65 deficiency and leukemia development is established in mice, experiments mainly using microarrays for gene expression profiling suggested normal expression of SLP-65 in human precursor B-cell ALL. This analysis however does not discriminate between normal and aberrant SLP-65 transcripts with the latter being unable to generate functional protein. To examine the correlation between SLP-65 deficiency and childhood precursor B-cell ALL, we determined SLP-65 expression in 119 precursor B-cell ALL samples by both RNA and protein methods. The expression of SLP-65 was compared to clinical and laboratory findings, cytogenetics as well as to the outcome data within this uniformly treated cohort of patients. Loss of slp-65 protein was significantly associated with the occurrence of the TEL/AML1 rearrangement (p=0.026) but not with any other clinical or cytogenetic feature. We found a profound disconnection between slp-65 mRNA and protein expression in 38 out of the 119 leukemic samples pointing to a posttranscriptional regulation of slp-65 (Table). To confirm that SLP-65 transcript expression does not automatically correlate with its protein expression, we analyzed a panel of human cell lines derived from precursor B-cell ALL patients. The cell lines HPB-NULL and BV-173 showed a deficiency in SLP-65 protein expression, although SLP-65 transcripts can easily be detected in both lines. Together, the data suggest that SLP-65 expression might be regulated at the posttranscriptional level and that the presence of SLP-65 transcripts does not necessarily lead to SLP-65 protein and function. In one particular patient, we found a truncated slp-65 transcript and the predicted slp-65 protein lacks its SH2 domain. We tested whether this SLP-65 protein lacking the SH2 domain is functional in pre-B cells. To this end, we transfected murine SLP-65 −/− pre-B cells with retroviral constructs for either wild-type (wt SLP-65) or truncated SLP-65 (SLP-65delSH2) and analysed pre-BCR downregulation, Ca2+ release and pre-B cell differentiation. The results showed that, in contrast to wt SLP-65, SLP-65delSH2 failed to induce any effects in the performed experiments. Together with previous findings showing that SLP-65-deficient mice develop pre-B cell leukemia, the data suggest that SLP-65 acts as a tumor suppressor that limits pre-B cell proliferation by inducing differentiation. Disconnection between slp-65 transcripts and protein expression total slp-65 protein+ (51 patients) slp-65 protein weak (19 patients) slp-65 protein- (49 patients) PCR+ 108 51(9 TEL/AML+, 42 TEL/AML-) 19 (9 TEL/AML+, 10 TEL/AML-) 38 (15 TEL/AML+, 23 TEL/AML-) PCR- 11 0 0 11 (T-ALL)

The Expression of the Adaptor Protein SLP-65 Is Freqently Lost in Childhood B-Lineage Acute Lymphoblastic Leukemia (ALL).

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1118-1118
Author(s):  
Arndt Borkhardt ◽  
Christine Damm-Welk ◽  
Jochen Harbott ◽  
Thomas Wossning ◽  
Bettina Storch ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
B Cells ◽  
Tumor Suppressor ◽  
Protein Expression ◽  
B Cell ◽  
Western Blotting ◽  
Adaptor Protein ◽  
Sh2 Domain ◽  
B Cell Differentiation ◽  
Rt Pcr

Abstract Objective: The adaptor protein SLP-65 (also known as BLNK or BASH) plays an essential role in B cell differentiation. A crucial consequence of SLP-65 deficiency in mice is the high incidence of pre-B cell leukemia, suggesting a tumor suppressor role for SLP-65 in pre-B cells. We recently demonstrated deficiency slp-65 in 16 out of 34 pre-B ALL samples from children (Jumaa et al., Nature, 2003). These data were recently questioned by another study in which slp-65 levels were found to be as high as in normal B cells (Imai, et al., Leukemia, 2004). To resolve this issue we investigated another series of 148 primary ALL-samples by quantitative RT-PCR, Western-blotting and sequencing of aberrant slp-65 transcripts. We provide evidence that a newly identified slp-65 aberration, with inclusion of a newly identified exon 11a, leads to a functionless slp-65 protein. Materials: Samples were collected at diagnosis and contained at least 80 % marrow blasts. Screening for the presence of the fusion genes BCR/ABL, MLL/AF4, or TEL/AML1 was done by standard RT-PCR. For immunophenotyping and classification into pro-B, pre-B, c-, B- or T-cell ALL we used the standard criteria. Slp-65 mRNA was measured by taqman technology, protein expression by Western blotting with the B-211 antibody. To assess the functional consequences of a truncated form of slp-65, we measured Ca-responsiveness of the pre-B cell receptor. Pre-B cell differentiation properties of the wildtype and the truncated isoform of slp-65 were functionally tested as described previously (Flemming et al., Nat. Immunol, 2003). Results: The slp-65 mRNA expression ranged widely among the samples but was not correlated to any of the clinical or genetically parameters tested, such as sex, Age, WBC, or event-free survival. With respect to the immunophenotype, slp-65 mRNA was extremely low in T-ALL and but highly expressed in pro-B-ALL (p<0.001). We found the inclusion of additional sequences between these exons named exon 3a (n=9), 3b (n= 16). By primers that specifically amplify exon 3a+b, we found 2 patients with exceptionally high expression of this aberrant slp-65 transcript. One drawback of quantitative RT-PCR analysis, however, is that aberrant transcripts and alternatively spliced forms are detected as normal transcripts, although they are unable to generate a functional protein. To check for full-length SLP-65 protein expression we applied Western-botting. We found truncated spl-65 protein variants in 23 samples and a total loss of the SLP 65 protein in 41 cases. We identified a novel transcript of slp-65 in which an additional exon (exon 11a) was inserted into the mRNA. Although low amounts of this 11a-transcript were also seen in normal B-cells, this aberrantly spliced slp-65 mRNA was dominantly expressed in 18 patients (2 pro-B-ALL, 12 c-ALL, 4 pre-B-ALL). Inclusion of exon 11a leads to a truncated slp-65 protein that lacks the SH-2 domain. The SH2 domain lacking SLP-65 form completely failed to induce calcium response and pre-B cell differentiation in vitro. Our data confirm the correlation between SLP-65 deficiency and leukemia and suggest a tumor suppressor role for SLP-65 in human pre-B cells.

The adaptor protein SH2D1A regulates signaling through CD150 (SLAM) in B cells

Blood ◽  
2004 ◽  
Vol 104 (13) ◽  
pp. 4063-4070 ◽  
Author(s):  
Svitlana V. Mikhalap ◽  
Larysa M. Shlapatska ◽  
Olga V. Yurchenko ◽  
Maria Y. Yurchenko ◽  
Ganna G. Berdova ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
B Cells ◽  
B Cell ◽  
Adaptor Protein ◽  
Sh2 Domain ◽  
B Cell Differentiation ◽  
Akt Phosphorylation ◽  
Inositol Phosphatase ◽  
Extracellular Signal ◽  
Inositol Phosphatases

Abstract The CD150 receptor is expressed on activated T and B lymphocytes, dendritic cells, and monocytes. A TxYxxV/I motif in the CD150 cytoplasmic tail can bind different SH2-containing molecules, including tyrosine and inositol phosphatases, Src family kinases, and adaptor molecules. To analyze CD150-initiated signal transduction pathways, we used DT40 B-cell sublines deficient in these molecules. CD150 ligation on DT40 transfectants induced the extracellular signal-regulated kinase (ERK) pathway, which required SH2-containing inositol phosphatase (SHIP) but not SH2 domain protein 1A (SH2D1A). CD150-mediated Akt phosphorylation required Syk and SH2D1A, was negatively regulated by Lyn and Btk, but was SHIP independent. Lyn directly phosphorylated Y327 in CD150, but the Akt pathway did not depend on CD150 tyrosine phosphorylation and CD150-SHP-2 association. Analysis of CD150 and SH2D1A expression in non-Hodgkin and Hodgkin lymphomas revealed stages of B-cell differentiation where these molecules are expressed alone or coexpressed. Signaling studies in Hodgkin disease cell lines showed that CD150 is linked to the ERK and Akt pathways in neoplastic B cells. Our data support the hypothesis that CD150 and SH2D1A are coexpressed during a narrow window of B-cell maturation and SH2D1A may be involved in regulation of B-cell differentiation via switching of CD150-mediated signaling pathways. (Blood. 2004;104:4063-4070)

Blimp1 Is a Tumor Suppressor Gene in Diffuse Large B Cell Lymphoma.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 446-446 ◽  
Author(s):  
Jonathan Mandelbaum ◽  
Govind Bhagat ◽  
Tongwei Mo ◽  
Alexander Tarakhovsky ◽  
Laura Pasqualucci ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
B Cells ◽  
Tumor Suppressor ◽  
B Cell ◽  
Tumor Suppressor Gene ◽  
B Cell Lymphoma ◽  
Suppressor Gene ◽  
Cell Phenotype ◽  
B Cell Differentiation

Abstract Abstract 446 The PRDM1/ BLIMP1 gene encodes a zinc finger transcriptional repressor that is expressed in a subset of germinal center (GC) B cells and in all plasma cells, and is required for terminal B cell differentiation. The BLIMP1 locus is biallelically inactivated by structural alterations in approximately one third of activated B cell-like diffuse large B cell lymphoma (ABC-DLBCL) (Pasqualucci et al, J Exp Med 2006). Moreover, the expression of the Blimp1 protein is absent in up to 80% of ABC-DLBCL due to alternative genetic and epigenetic mechanisms. These findings suggest that BLIMP1 may function as a tumor suppressor gene whose loss may contribute to the pathogenesis of this lymphoma type by blocking terminal B cell differentiation. To investigate the role of BLIMP1 inactivation in lymphomagenesis in vivo, we tested whether conditional deletion of the Blimp1 gene in mouse B cells can promote the growth of lymphomas recapitulating the features of ABC-DLBCL. Toward this end, a mouse model carrying a loxP-flanked exon 5 of the Blimp1 gene that can be deleted by Cre-mediated recombination (Ohinata et al, Nature 2005) was crossed with a CD19-Cre deletor strain, expressing the Cre recombinase in all B cells. The resulting mice were monitored for tumor development and survival. Consistent with previous observations in a similar model (Shapiro-Shelef et al, Immunity 2003), Blimp1 conditional knockout (Blimp1CD19KO) mice showed a severe impairment in the generation of CD138+ plasma cells and had decreased serum immunoglobulin levels of all isotypes, together with a two-fold increase in the number of PNAhiCD95+ GC B cells. Over time, significantly reduced survival was observed in the Blimp1CD19KO cohort, with only 27% of the animals being alive at 15 months of age (LogRank p value<0.0001). Macroscopic and flow cytometric analysis of the lymphoid compartments revealed the presence of splenomegaly in 32/38 (84%) Blimp1CD19KO, as compared to 1/25 (4%) age-matched wildtype (WT) littermates, and a significant increase in IgM+IgD-CD21+CD23lo splenic B cells, indicative of marginal zone B cell expansion. In addition, 79% (n=30/38) of Blimp1CD19KO mice showed markedly hyperplastic bronchus-associated lymphoid tissue (BALT). Notably, between 10 and 16 months of age 34% (13/38) of these animals developed clonal lymphoproliferative disorders with a mature B cell phenotype (B220+Pax5+) and histologic features of DLBCL (n=6) or less aggressive lymphoid proliferations (LPD: n=6; marginal zone lymphoma: n=1), in contrast with 1/27 heterozygous and 0/25 WT animals. Sequencing analysis of the rearranged immunoglobulin variable region genes in lymphoma biopsies revealed the presence of somatic mutations in 6/8 samples investigated, demonstrating their origin from a GC-experienced B cell. Moreover, immunohistochemical staining for Bcl6 and Irf4 documented a late-GC “activated” B cell phenotype (Bcl6-Irf4+) in all tumors tested (n=4), consistent with the expansion of cells that had been committed to plasma cell differentiation. These data demonstrate that Blimp1 is a bona-fide tumor suppressor gene whose B-cell specific inactivation in vivo promotes the development of lymphomas sharing features of the human ABC-DLBCL. Disclosures: No relevant conflicts of interest to declare.

Differentiation-Stage-Specific Expression of MicroRNAs in B-Lymphocytes and Diffuse Large B-Cell Lymphomas (DLBCL)

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 805-805 ◽  
Author(s):  
Raquel Malumbres ◽  
Robert Tibshirani ◽  
Elena Cubedo ◽  
Kristopher A Sarosiek ◽  
Xiaoyu Jiang ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
B Cells ◽  
B Cell ◽  
Cell Lines ◽  
Memory B Cells ◽  
Microrna Expression ◽  
B Cell Differentiation ◽  
Cell Of Origin ◽  
Specific Expression ◽  
Differentiation Stage

Abstract B-cell development and differentiation are complex processes controlled by distinct programs of transcriptional control. A large set of transcriptional factors together or in succession control this process and their deregulation may result in block of differentiation or malignant transformation. MicroRNAs are small RNAs that orchestrate cellular functions by modulating the level of their targeted proteins by either translational arrest or transcript degradation, and play a key role in cell differentiation, apoptosis, proliferation and cancer development. An increasing number of transcription factors are being found targeted by microRNAs. Emerging evidence suggests that differentiation stage-specific expression of microRNAs occurs in the hematopoietic system and during T cell differentiation. Only limited information exists on microRNA expression in normal B cell differentiation and its malignant counterparts. Herein we analyzed microRNA expression profiles in distinct peripheral B cell differentiation stages-naïve, germinal center (GC) centroblasts and memory cells as well as tonsilar T cells. Furthermore, microRNA profiling was performed in germinal center-like (GCB-like) and activated B-cell-like (ABC-like) DLBCL cell lines originating from distinct B-cell differentiation stages. RNA, extracted with mirVana kit (AMBION) from B cell subsets and T cells enriched from normal tonsils was hybridized on LC Sciences (Houston, TX) microarrays harboring 470 human microRNAs probes (Sanger miRBase Release 9.1). Expression of selected microRNAs was confirmed by ABI RT-PCR methodology. Unsupervised clustering of microRNAs with values present in at least 50% of the samples (122 probes) resulted in perfect differentiation-stage clustering of samples. Application of Statistical Analysis of Microarrays (SAM) and Prediction Analysis of Microarrays (PAM) methods (FDR= 10%) identified a 47 microRNA cell of origin classifier for B-cells differentiation stage; 27 of these microRNAs were upregulated and 20 downregulated in centroblasts compared to memory B-cells. MicroRNAs belonging to paralog microRNA clusters (e.g. miR17-92-1, miR363-106a and miR25-106b) demonstrated similar patterns of expression in specific differentiation stages. To identify specific microRNA targets, miRanda, TargetScan and PicTar programs were used. To experimentally confirm the targets, we assessed the effects of specific microRNAs on the expression levels of targeted proteins and on the luciferase reporter under the control of the wild type and mutated 3′ UTR regions of putative target genes. Using this experimental approach we identified lymphocyte-stage-specific microRNAs which expression inversely correlated and might regulate the expression of LMO2, BLIMP1 and IRF4 proteins distinctively expressed at different differentiation stages of B lymphocytes. For example, miR223, which expression is low in GC cells but is high in naïve and memory B cells, downregulates the expression of LMO2. We next analyzed microRNA expression in DLBCL cell lines. Clustering analysis, using the 47 microRNA cell of origin classifier perfectly classified GCB-like and ABC-like cell lines. Interestingly, the expression of microRNAs in both GCB-like and ABC-like DLBCL cell lines was more similar to normal centroblasts than to memory B cells, suggesting that both may originate from distinct subpopulations of GC lymphocytes. The similarity of microRNA expression in cell lines to centroblasts was striking, with only 16 microRNAs (1 upregulated and 15 downregulated in cell lines) showing noticeable differences in levels of expression compared to normal cells. These microRNAs might be involved in the process of lymphoma transformation. SAM analysis aimed to differentiate GCB-like and ABC-like cell lines identified 11 microRNAs, only 3 of which were present in the cell of origin classifier. This observation suggests that there is also a difference in expression of microRNAs not directly related to the distinct cell of origin between the DLBCL subtypes. In summary, our results demonstrate that the microRNA profile changes during the GC reaction as well as during malignant transformation. Specific microRNAs can regulate key transcription factors controlling the processes of lymphocyte differentiation and transformation.

EBV MicroRNA Expression in Virus Driven B-Cell Differentiation and Lymphomagenesis.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 93-93
Author(s):  
Jamie P Nourse ◽  
Pauline Crooks ◽  
Do Nguyen Van ◽  
Kimberley Jones ◽  
Nathan Ross ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Differentiation ◽  
B Cells ◽  
B Cell ◽  
Cell Lines ◽  
Phase 1 ◽  
Differentiation Process ◽  
B Cell Differentiation ◽  
B Cell Lymphomas

Abstract Abstract 93 Lymphomagenesis is a complex process, in part reflecting the nature of the transforming event, as well as the developmental stage of the cell. In the B-cell differentiation represents a continuum that is initiated when a naïve B-cell encounters antigen, undergoes a germinal centre (GC) reaction and ends with terminal differentiation into either a memory or plasma B-cell. Interruption of this process by a transforming event may result in a clonal proliferation where differentiation of the cell is blocked at this stage. The majority of B-cell lymphomas are derived from GC or post-GC B-cells. As physiologically relevant human models that emulate the various stages of B-cell differentiation are lacking we rationalized that in-vitro utilization of the B-cell lymphotrophic Epstein-Barr virus (EBV) would provide insights into this process. In one scenario, EBV infects naïve B-cells and drives a differentiation process paralleling the GC reaction through a well-characterized series of latency gene expression programs. EBV is also implicated in a range of GC and post-GC derived B-cell lymphomas (including Burkitt's, Hodgkin's, PTLD and DLBCL). Using high efficiency EBV infection of isolated naïve B-cells from EBV seronegative subjects, we have demonstrated that EBV infection provides a highly relevant in-vitro model that accurately reflects three distinct phases in the GC differentiation process. Alterations in the expression of a broad range of genes associated with the differentiation of the naïve B-cell were observed within 24 hours of infection and within four days of infection a process exhibiting many similarities to the GC reaction had taken place. These included BCL6, the levels of which were rapidly down-regulated within 24 hours indicating activation of the naïve B-cell. Levels of the memory cell marker CD27 steadily increased over 24 to 96 hours, while BLIMP1 expression increased, peaking at 48 hours. An increase in AID expression over 8 to 48 hours was consistent with somatic hypermutation and isotype switching. Finally a dramatic elevation in expression of the GC associated oncogene LMO2 was observed after two days followed by an equally dramatic downregulation after two weeks. Within two weeks of infection (phase 1), B-cells progressed through a GC-like phase followed by a one week transition state (phase 2) after which continued culture resulted in further differentiation to cells with the phenotypic hallmarks of post-GC cells (phase 3). MicroRNAs (miRNAs) are small non-coding RNAs, which act as negative regulators of gene expression. miRNA expression reflects the developmental lineage and differentiation state of several human cancers and over-expression is implicated in lymphomagenesis. They are also associated with the development of the GC reaction. EBV expresses at least 39 unique miRNAs from the BART and BHRF1 clusters within the viral genome. These EBV miRNAs are differentially expressed in tumour cell lines, suggesting roles during EBV-driven B-cell differentiation and lymphomagenesis. The relationship between EBV miRNAs and the kinetics of EBV driven B-cell differentiation has not been characterized. In our model we find distinct miRNA expression kinetics, coincidental with gene expression changes during B-cell differentiation, suggesting that these regulatory molecules may be involved in the GC process. Although a small number of EBV miRNAs were expressed at low levels early in the GC-like phase 1, the majority were up-regulated during the transition phase 2, exhibiting a subsequent partial down-regulation in the post-GC-like phase 3. The three phases were coincident with differential BART and BHRF1 promoter usage and alternate splicing. Strikingly, application of the infection model to primary patient samples and lymphoma cell-lines revealed that lymphomas clustered within distinct phases, reflecting the full continuum of the B-cell differentiation process. Interestingly, the majority of PTLD samples clustered within the transition phase, whereas Burkitt's and Hodgkin's lymphoma sample segregated with the GC stage. Application of our gene expression and miRNA data to cell-lines and a range of GC and post-GC EBV-positive lymphomas of various histological types indicate that our B-cell differentiation model can be used to accurately classify B-cell lymphomas in a physiologically relevant manner according to the stage of arrested B-cell differentiation. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Expression of A-myb, but not c-myb and B-myb, is restricted to Burkitt's lymphoma, sIg+ B-acute lymphoblastic leukemia, and a subset of chronic lymphocytic leukemias

Blood ◽  
1996 ◽  
Vol 87 (5) ◽  
pp. 1900-1911 ◽  
Author(s):  
J Golay ◽  
M Luppi ◽  
S Songia ◽  
C Palvarini ◽  
L Lombardi ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Cell Differentiation ◽  
Acute Lymphoblastic Leukemia ◽  
B Cells ◽  
B Cell ◽  
Cell Lines ◽  
Lymphoblastic Leukemia ◽  
Burkitt’S Lymphoma ◽  
Burkitt's Lymphoma ◽  
B Cell Differentiation

Abstract The A-myb gene encodes a transcription factor that is related both functionally and structurally to the v-myb oncogene. Following our observations that A-myb is expressed in a restricted subset of normal mature human B lymphocytes, with the phenotype CD38+, CD39-, slgM-, we have now investigated the pattern of A-myb expression in neoplastic B cells representating the whole spectrum of B-cell differentiation and compared it to that of c-myb and B-myb. In a panel of 32 B-cell lines, A-myb was very strongly expressed in most Burkitt's lymphoma (BL) cell lines, but weak or negative in 2 pre-B acute lymphoblastic leukemia (ALL), 4 non-Hodgkin's lymphoma (NHL), 6 Epstein-Barr virus- immortalized lymphoblastoid cell lines, and 6 myeloma lines. Protein expression paralleled that of the RNA. We have also investigated A-myb expression in 49 fresh cases of B leukemias. Among 24 ALL, 6 were of the null and 11 of the common type and all these were negative for A- myb expression; on the other hand, all 7 B-ALL cases (slg+), as well as one fresh BL case with bone marrow infiltration, expressed A-myb. A-myb was undetectable in 4 prolymphocytic leukemias (PLL) but was strongly expressed in 5/20 (25%) of chronic lymphocytic leukemia (CLL) samples. In the latter A-myb did not correlate with phenotype or clinical stage. Finally, we have studied the progression of one case of CLL into Richter's syndrome and have found that the Richter's cells expressed about 25-fold less A-myb RNA than the CLL cells from the same patient. The pattern of c-myb and B-myb was clearly distinct from that of A-myb. C-myb and B-myb were expressed in all neoplastic groups, except in CLL cells. Thus, A-myb expression, unlike that of c-myb and B-myb, is restricted to a subset of B-cell neoplasias (in particular BL and slg+B- ALL) representative of a specific stage of B-cell differentiation. This expression may in part reflect expression of A-myb by the normal germinal center B cells that are the normal counterpart of these transformed B cells. The data presented strongly support a role for this transcription factor in B-cell differentiation and perhaps in B- cell transformation in some neoplasias.

scholarly journals G protein subunit G alpha 16 expression is restricted to progenitor B cells during human B-cell differentiation

Blood ◽  
1995 ◽  
Vol 85 (7) ◽  
pp. 1836-1842 ◽  
Author(s):  
MY Mapara ◽  
K Bommert ◽  
RC Bargou ◽  
C Leng ◽  
C Beck ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
B Cells ◽  
B Cell ◽  
Cell Line ◽  
Cell Lines ◽  
B Cell Lymphoma ◽  
Cell Phenotype ◽  
Low Grade ◽  
B Cell Differentiation ◽  
Human B Cell

Recently G alpha 16, a new guanosine triphosphate (GTP) binding protein alpha subunit has been described to be specifically expressed in human hematopoietic cells. Expression of G alpha 16 was observed in human cell lines of myelomonocytic and T-lymphocytic origin, but not in human B-cell lines Raji and IM9. We studied the expression of G alpha 16 in human B cells corresponding to different stages of B-cell differentiation by means of reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting. The human Burkitt's lymphoma cell lines Raji, Ramos, BJAB, the lymphoblastoid cell line SKW6.4, and the plasmocytoma cell line U266 were devoid of G alpha 16. In contrast, G alpha 16 was detected in the human progenitor B cell lines Reh and Nalm-6. Using the mu+, k-cell line BLIN-1 (pre-B cell phenotype) and its derived subclone 1E8 (surface mu+, k+; B-cell phenotype) G alpha 16 expression was found to disappear on transition from pre-B to B-cell differentiation stage. The analysis of a broad panel of human neoplastic B lymphocytes ranging from progenitor B-acute lymphatic leukemia (pre-pre-B-ALL), common acute leukemias (cALL), pre-B-ALL, mature B-ALL to low grade B-cell lymphoma (chronic lymphocytic leukemia of B-cell type, leukemic centrocytic non-Hodgkins lymphoma [NHL], hairy cell leukemia) showed that G alpha 16 expression is limited to progenitor and pre-B-ALL cells. Therefore, we conclude that within B-cell differentiation, G alpha 16 is expressed solely during early B cell ontogeny and downregulated during differentiation. Thus, G alpha 16 might be an important regulator involved in signaling processes in progenitor B cells.

scholarly journals Humoral helper activity for B-cell differentiation released from non- Hodgkin's lymphoma cells having both SRBC and complement receptors in the pokeweed mitogen system

Blood ◽  
1981 ◽  
Vol 57 (6) ◽  
pp. 1074-1080
Author(s):  
N Moriya ◽  
T Miyawaki ◽  
Y Ueno ◽  
S Koizumi ◽  
N Taniguchi
Keyword(s):  
T Cells ◽  
Cell Differentiation ◽  
B Cells ◽  
B Cell ◽  
Plasma Cells ◽  
Lymphoid Cells ◽  
Pokeweed Mitogen ◽  
Complement Receptors ◽  
B Cell Differentiation ◽  
Cell Leukemia

Abstract The majority of lymphoid cells from a patient with non-Hodgkin's lymphoma with leukemic transformation were demonstrated to carry receptors for both sheep erythrocytes and complements by the combined rosette assay using neuraminidase-treated sheep erythrocytes and complement-coated zymosan beads. Most of them were considered morphologically lymphoblasts and were positive for acid phosphatase staining. Terminal deoxynucleotidyl transferase activity was not detected in these cells. Lymphoid cells from this patient did not respond to the stimulation with phytohemagglutinin-P, concanavalin-A, and pokeweed mitogen (PWM). When these cells were cultured with PWM for 7 days, no plasma cell was generated. Although only a few plasma cells were generated in the PWM-stimulated culture of normal purified B cells alone, the addition of the patient's cells to purified normal B cells resulted in a markedly enhanced generation of plasma cells in response to PWM, as was the case with normal T cells. But leukemic cells either from a patient with T-cell leukemia not having complement receptors or from a patient with null-cell leukemia showed no enhancing ability in B- cell differentiation. In addition, the culture supernates of the patient's cells obtained after 24-hr PWM stimulation had an ability to promote B-cell differentiation comparable in activity to those from the PWM-stimulated normal T cells.

scholarly journals T cell-derived B cell differentiation factor(s). Effect on the isotype switch of murine B cells.

1982 ◽  
Vol 155 (3) ◽  
pp. 734-748 ◽  
Author(s):  
P C Isakson ◽  
E Puré ◽  
E S Vitetta ◽  
P H Krammer
Keyword(s):  
Cell Differentiation ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cell Lines ◽  
Interleukin 2 ◽  
B Cell Differentiation ◽  
Differentiation Factor ◽  
T Cell Lines ◽  
Cell Differentiation Factor

Culturing BALB/c B cells for 6 d at low cell density in the presence of lipopolysaccharide (LPS) results in the appearance of a small number of IgG plaque-forming cells (PFC). The addition of supernatants from concanavalin A (Con A)-induced alloreactive (AKR anti-B6) long-term T cell lines (PK 7.1.1a and 7.1.2) or a T cell hybridoma (FS7-6.18) to LPS-treated B cells resulted in a marked increase in IgG PFC (3--10-fold higher than in cultures treated with LPS alone. The number of induced IgG PFC was not affected by removing IgG-bearing cells on the fluorescence-activated cell sorter, indicating that T cell-derived B cell differentiation factor enhances isotype switching of sIgG- cells, rather than selecting and expanding pre-existing subpopulations of sIgG+ cells. We also investigated the subclass of IgG produced in the absence or presence of T cell factors and found that PK 7.1.1a, PK 7.1.2, and FS7-6.18 supernatants selectively increased IgG1 production. Several other T cell supernatants containing a variety of lymphokines had no effect, suggesting that PK 7.1.1a, PK 7.1.2, and FS7-6.18 lines produce factor(s) that can specifically enhance the recovery of IgG secreting cells in culture in the presence of LPS. These factors, which we have termed B cell differentiation factors, are different from interleukin 1, interleukin 2, T cell-replacing factor, colony-stimulating factor, macrophage-activating factor, and immune interferon. Our results suggest that soluble factors produced by T cell lines and hybridomas can markedly influence both the class and subclass of Ig produced by B cells.

scholarly journals Humoral helper activity for B-cell differentiation released from non- Hodgkin's lymphoma cells having both SRBC and complement receptors in the pokeweed mitogen system

Blood ◽  
1981 ◽  
Vol 57 (6) ◽  
pp. 1074-1080 ◽  
Author(s):  
N Moriya ◽  
T Miyawaki ◽  
Y Ueno ◽  
S Koizumi ◽  
N Taniguchi
Keyword(s):  
T Cells ◽  
Cell Differentiation ◽  
B Cells ◽  
B Cell ◽  
Plasma Cells ◽  
Lymphoid Cells ◽  
Pokeweed Mitogen ◽  
Complement Receptors ◽  
B Cell Differentiation ◽  
Cell Leukemia

The majority of lymphoid cells from a patient with non-Hodgkin's lymphoma with leukemic transformation were demonstrated to carry receptors for both sheep erythrocytes and complements by the combined rosette assay using neuraminidase-treated sheep erythrocytes and complement-coated zymosan beads. Most of them were considered morphologically lymphoblasts and were positive for acid phosphatase staining. Terminal deoxynucleotidyl transferase activity was not detected in these cells. Lymphoid cells from this patient did not respond to the stimulation with phytohemagglutinin-P, concanavalin-A, and pokeweed mitogen (PWM). When these cells were cultured with PWM for 7 days, no plasma cell was generated. Although only a few plasma cells were generated in the PWM-stimulated culture of normal purified B cells alone, the addition of the patient's cells to purified normal B cells resulted in a markedly enhanced generation of plasma cells in response to PWM, as was the case with normal T cells. But leukemic cells either from a patient with T-cell leukemia not having complement receptors or from a patient with null-cell leukemia showed no enhancing ability in B- cell differentiation. In addition, the culture supernates of the patient's cells obtained after 24-hr PWM stimulation had an ability to promote B-cell differentiation comparable in activity to those from the PWM-stimulated normal T cells.

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