1
|
Bauvois B, Nguyen-Khac F, Merle-Béral H, Susin SA. CD38/NAD + glycohydrolase and associated antigens in chronic lymphocytic leukaemia: From interconnected signalling pathways to therapeutic strategies. Biochimie 2024:S0300-9084(24)00165-2. [PMID: 39009062 DOI: 10.1016/j.biochi.2024.07.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2024] [Accepted: 07/12/2024] [Indexed: 07/17/2024]
Abstract
Chronic lymphocytic leukaemia (CLL) is a heterogenous disease characterized by the accumulation of neoplastic CD5+/CD19+ B lymphocytes. The spreading of the leukaemia relies on the CLL cell's ability to survive in the blood and migrate to and proliferate within the bone marrow and lymphoid tissues. Some patients with CLL are either refractory to the currently available therapies or relapse after treatment; this emphasizes the need for novel therapeutic strategies that improving clinical responses and overcome drug resistance. CD38 is a marker of a poor prognosis and governs a set of survival, proliferation and migration signals that contribute to the pathophysiology of CLL. The literature data evidence a spatiotemporal association between the cell surface expression of CD38 and that of other CLL antigens, such as the B-cell receptor (BCR), CD19, CD26, CD44, the integrin very late antigen 4 (VLA4), the chemokine receptor CXCR4, the vascular endothelial growth factor receptor-2 (VEGF-R2), and the neutrophil gelatinase-associated lipocalin receptor (NGAL-R). Most of these proteins contribute to CLL cell survival, proliferation and trafficking, and cooperate with CD38 in multilayered signal transduction processes. In general, these antigens have already been validated as therapeutic targets in cancer, and a broad repertoire of specific monoclonal antibodies and derivatives are available. Here, we review the state of the art in this field and examine the therapeutic opportunities for cotargeting CD38 and its partners in CLL, e.g. by designing novel bi-/trispecific antibodies.
Collapse
Affiliation(s)
- Brigitte Bauvois
- Centre de Recherche des Cordeliers, Sorbonne Université, Université Paris Cité, Inserm UMRS1138, Drug Resistance in Hematological Malignancies Team, F-75006, Paris, France.
| | - Florence Nguyen-Khac
- Centre de Recherche des Cordeliers, Sorbonne Université, Université Paris Cité, Inserm UMRS1138, Drug Resistance in Hematological Malignancies Team, F-75006, Paris, France; Sorbonne Université, Groupe Hospitalier Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Service d'Hématologie Biologique, F-75013, Paris, France.
| | - Hélène Merle-Béral
- Centre de Recherche des Cordeliers, Sorbonne Université, Université Paris Cité, Inserm UMRS1138, Drug Resistance in Hematological Malignancies Team, F-75006, Paris, France.
| | - Santos A Susin
- Centre de Recherche des Cordeliers, Sorbonne Université, Université Paris Cité, Inserm UMRS1138, Drug Resistance in Hematological Malignancies Team, F-75006, Paris, France.
| |
Collapse
|
2
|
Nédellec S, Renaudineau Y, Bordron A, Berthou C, Porakishvili N, Lydyard PM, Pers JO, Youinou P. B cell response to surface IgM cross-linking identifies different prognostic groups of B-chronic lymphocytic leukemia patients. THE JOURNAL OF IMMUNOLOGY 2005; 174:3749-56. [PMID: 15749915 DOI: 10.4049/jimmunol.174.6.3749] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
On the basis of responses to surface IgM (sIgM) cross-linking, B cells from 41 patients with B-chronic lymphocytic leukemia were categorized as 15 nonresponders (group I) and 26 responders (group II). The latter cases were subclassified as those seven where proliferation was induced (subgroup IIa) and the remaining 19 in whom apoptosis occurred (subgroup IIa). Signal disruption in group I was confirmed by the absence of Ca2+ mobilization. Activation of PI3K was constitutive in subgroup IIa, but not in subgroup IIb, and that of Akt induced by anti-mu in subgroup IIa, but not in subgroup IIb. Among the MAPK, ERK was more highly activated relative to p38 in subgroup IIa, whereas activation of p38 predominated over that of ERK in subgroup IIb. For subgroup IIb cells, based on tyrosine phosphorylation and translocation into lipid rafts, sIgM signaling was shown to be enhanced by Zap70. The different consequences of signaling through sIgM were associated with biological prognosis indicators. These included high levels of CD38, lack of mutations in the IgVH chain genes, preferential usage of full-length CD79b, and severe clinical stage. Thus, modification of sIgM-induced signaling could be a therapeutic approach.
Collapse
MESH Headings
- Adult
- Aged
- Aged, 80 and over
- Apoptosis
- B-Lymphocytes/immunology
- B-Lymphocytes/metabolism
- B-Lymphocytes/pathology
- Calcium Signaling
- Case-Control Studies
- Cell Proliferation
- Cross-Linking Reagents
- Female
- Humans
- Immunoglobulin M/metabolism
- In Vitro Techniques
- Leukemia, Lymphocytic, Chronic, B-Cell/classification
- Leukemia, Lymphocytic, Chronic, B-Cell/immunology
- Leukemia, Lymphocytic, Chronic, B-Cell/metabolism
- Leukemia, Lymphocytic, Chronic, B-Cell/pathology
- Male
- Middle Aged
- Mitogen-Activated Protein Kinase Kinases/metabolism
- Phosphorylation
- Prognosis
- Protein-Tyrosine Kinases/metabolism
- Receptors, Antigen, B-Cell/metabolism
- Signal Transduction
- ZAP-70 Protein-Tyrosine Kinase
Collapse
Affiliation(s)
- Steven Nédellec
- Institut de Synergie des Sciences et de la Santé, Brest University Medical School, Brest, France
| | | | | | | | | | | | | | | |
Collapse
|
3
|
Chen L, Apgar J, Huynh L, Dicker F, Giago-McGahan T, Rassenti L, Weiss A, Kipps TJ. ZAP-70 directly enhances IgM signaling in chronic lymphocytic leukemia. Blood 2004; 105:2036-41. [PMID: 15514014 DOI: 10.1182/blood-2004-05-1715] [Citation(s) in RCA: 178] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chronic lymphocytic leukemia (CLL) B cells that express unmutated immunoglobulin heavy-chain variable region genes (IgV(H)) generally express ZAP-70, in contrast to normal B cells or most CLL cases with mutated IgV(H). Following IgM ligation, ZAP-70+ CLL cells had significantly higher levels of phosphorylated p72(Syk), BLNK, and phospholipase-Cgamma (PLCgamma) and had greater[Ca2+]i flux than did ZAP-70-negative CLL cases, including unusual ZAP-70-negative cases with unmutated IgV(H). IgM ligation of ZAP-70-negative CLL B cells infected with an adenovirus vector encoding ZAP-70 induced significantly greater levels of phosphorylated p72(Syk), BLNK, and PLCgamma and had greater[Ca2+]i flux than did similarly stimulated, noninfected CLL cells or CLL cells infected with a control adenovirus vector. We conclude that expression of ZAP-70 in CLL allows for more effective IgM signaling in CLL B cells, a feature that could contribute to the relatively aggressive clinical behavior generally associated with CLL cells that express unmutated IgV(H).
Collapse
Affiliation(s)
- Liguang Chen
- Division of Hematology/Oncology, Department of Medicine, University of California, San Diego, 9500 Gilman Dr, UCSD School of Medicine, La Jolla, CA 92093, USA
| | | | | | | | | | | | | | | |
Collapse
|
4
|
Chen L, Widhopf G, Huynh L, Rassenti L, Rai KR, Weiss A, Kipps TJ. Expression of ZAP-70 is associated with increased B-cell receptor signaling in chronic lymphocytic leukemia. Blood 2002; 100:4609-14. [PMID: 12393534 DOI: 10.1182/blood-2002-06-1683] [Citation(s) in RCA: 385] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We examined isolated leukemia B cells of patients with chronic lymphocytic leukemia (CLL) for expression of zeta-associated protein 70 (ZAP-70). CLL B cells that have nonmutated immunoglobulin variable region genes (V genes) expressed levels of ZAP-70 protein that were comparable to those expressed by normal blood T cells. In contrast, CLL B cells that had mutated immunoglobulin variable V genes, or that had low-level expression of CD38, generally did not express detectable amounts of ZAP-70 protein. Leukemia cells from identical twins with CLL were found discordant for expression of ZAP-70, suggesting that B-cell expression of ZAP-70 is not genetically predetermined. Ligation of the B-cell receptor (BCR) complex on CLL cells that expressed ZAP-70 induced significantly greater tyrosine phosphorylation of cytosolic proteins, including p72(Syk), than did similar stimulation of CLL cells that did not express ZAP-70. Also, exceptional cases of CLL cells that expressed mutated immunoglobulin V genes and ZAP-70 also experienced higher levels tyrosine phosphorylation of such cytosolic proteins following BCR ligation. Following BCR ligation, ZAP-70 underwent tyrosine phosphorylation and became associated with surface immunoglobulin and CD79b, arguing for the involvement of ZAP-70 in BCR signaling. These data indicate that expression of ZAP-70 is associated with enhanced signal transduction via the BCR complex, which may contribute to the more aggressive clinical course associated with CLL cells that express nonmutated immunoglobulin receptors.
Collapse
MESH Headings
- B-Lymphocytes/immunology
- B-Lymphocytes/metabolism
- Diseases in Twins
- Enzyme Precursors/metabolism
- Gene Expression Regulation, Leukemic
- Gene Rearrangement, B-Lymphocyte
- Genes, Immunoglobulin
- Humans
- Immunoglobulin Heavy Chains/genetics
- Immunoglobulin Variable Region/genetics
- Intracellular Signaling Peptides and Proteins
- Leukemia, Lymphocytic, Chronic, B-Cell/immunology
- Leukemia, Lymphocytic, Chronic, B-Cell/metabolism
- Neoplasm Proteins/biosynthesis
- Neoplasm Proteins/genetics
- Neoplasm Proteins/physiology
- Phosphorylation
- Protein Processing, Post-Translational
- Protein-Tyrosine Kinases/biosynthesis
- Protein-Tyrosine Kinases/genetics
- Protein-Tyrosine Kinases/metabolism
- Protein-Tyrosine Kinases/physiology
- Receptors, Antigen, B-Cell/immunology
- Signal Transduction
- Syk Kinase
- ZAP-70 Protein-Tyrosine Kinase
Collapse
Affiliation(s)
- Liguang Chen
- Division of Hematology/Oncology, Department of Medicine, University of California, San Diego for the CLL Research Consortium, San Diego, CA, USA
| | | | | | | | | | | | | |
Collapse
|
5
|
Gordon MS, Kato RM, Lansigan F, Thompson AA, Wall R, Rawlings DJ. Aberrant B cell receptor signaling from B29 (Igbeta, CD79b) gene mutations of chronic lymphocytic leukemia B cells. Proc Natl Acad Sci U S A 2000; 97:5504-9. [PMID: 10792036 PMCID: PMC25858 DOI: 10.1073/pnas.090087097] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Chronic lymphocytic leukemia (CLL) B cells characteristically exhibit low or undetectable surface B cell receptor (BCR) and diminished responses to BCR-mediated signaling. These features suggest that CLL cells may have sustained mutations affecting one or more of the BCR proteins required for receptor surface assembly and signal transduction. Loss of expression and mutations in the critical BCR protein B29 (Igbeta, CD79b), are prevalent in CLL and could produce the hallmark features of these leukemic B cells. Because patient CLL cells are intractable to manipulation, we developed a model system to analyze B29 mutations. Jurkat T cells stably expressing micro, kappa, and mb1 efficiently assembled a functional BCR when infected with recombinant vaccinia virus bearing wild-type B29. In contrast, a B29 CLL mutant protein truncated in the transmembrane domain did not associate with mu or mb1 at the cell surface. Another B29 CLL mutant lacking the C-terminal immunoreceptor tyrosine activation motif tyrosine and distal residues brought the receptor to the surface as well as wild-type B29 but showed significant impairment in anti-IgM-stimulated signaling events including mitogen-activated protein kinase activation. These findings demonstrate that B29 mutations previously identified in CLL patients can affect BCR-dependent signaling and may contribute to the unresponsive B cell phenotype in CLL. Finally, the features of the B29 mutations in CLL predict that they may be generated by somatic hypermutation.
Collapse
MESH Headings
- Antigens, CD/genetics
- Antigens, CD/immunology
- B-Lymphocytes/immunology
- CD79 Antigens
- Flow Cytometry
- Humans
- Immunoglobulin M/immunology
- Jurkat Cells
- Leukemia, Lymphocytic, Chronic, B-Cell/genetics
- Leukemia, Lymphocytic, Chronic, B-Cell/immunology
- Mutagenesis, Site-Directed
- Mutation
- Receptors, Antigen, T-Cell/genetics
- Receptors, Antigen, T-Cell/immunology
- Signal Transduction/immunology
- Tumor Cells, Cultured
Collapse
Affiliation(s)
- M S Gordon
- Molecular Biology Institute, Department of Microbiology, Division of Immunology/Rheumatology, University of California School of Medicine, Los Angeles, CA 90095, USA
| | | | | | | | | | | |
Collapse
|
6
|
Osorio LM, Aguilar-Santelises M. Apoptosis in B-chronic lymphocytic leukaemia. Cancer Immunol Immunother 1998; 15:234-40. [PMID: 9951686 DOI: 10.1007/bf02787206] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
B-chronic lymphocytic leukaemia (B-CLL) is characterised by the progressive accumulation of monoclonal B cells, which may be the result of several factors leading to extended B-CLL cell lifespan, increased proliferative capacity and diminished cell death. Here we review the implications of several signals mediated by receptors, such as surface IgM, CD6 and CD40, for the B-CLL cell survival, together with data on gene modulation in relation to the apoptosis process in B-CLL cells. We also describe some features of the Fas/FasL system in B-CLL that hypothetically might contribute to the accumulation of leukaemic cells and the progression of the disease, by downregulating the apoptotic response or avoiding the autologous immune response.
Collapse
Affiliation(s)
- L M Osorio
- Hematology Department, Karolinska Hospital, Stockholm, Sweden.
| | | |
Collapse
|
7
|
Lankester AC, Schijndel GM, Pakker NG, Van Oers RH, van Lier RA. Antigen receptor function in chronic lymphocytic leukemia B cells. Leuk Lymphoma 1996; 24:27-33. [PMID: 9049959 DOI: 10.3109/10428199609045711] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Functional studies revealed that two groups of B chronic lymphocytic leukemia (B-CLL) can be distinguished based on their capacity to mount a proliferative response following B-cell antigen receptor (BCR) cross-linking. The molecular basis for the functional distinction between these B-CLL groups most probably resides within or proximal to the BCR since non-responsive B-CLL, in marked contrast to responsive B-CLL, do not respond to BCR ligation with tyrosine phosphorylation of cellular substrates and increases in the free intracellular [Ca++]. Detailed biochemical analysis showed overall structural identity between responsive and non-responsive B-CLL with respect to both transmembrane and intracellular associates of the BCR complex. However expression levels of the protein tyrosine kinase syk, which is a key enzyme for the early signalling through the BCR, were found to be markedly lower in non-proliferating B-CLL. Here we will review current functional and biochemical data on responding and non-responding B-CLL and discuss the relevance of these findings for disease progression and our insight into the immunobiology of B-CLL.
Collapse
Affiliation(s)
- A C Lankester
- Central Laboratory of The Netherlands Red Cross Blood Transfusion Service, University of Amsterdam, The Netherlands
| | | | | | | | | |
Collapse
|
8
|
Garcia CA, Rosén A, Aguilar-Santelises M, Jondal M, Mellstedt H. Higher proliferative response in B-chronic lymphocytic leukemia (B-CLL) as compared to B-monoclonal lymphocytosis of undetermined significance (B-MLUS) after stimulation with Staphylococcus aureus and anti-CD40 monoclonal antibodies. Leuk Res 1993; 17:933-9. [PMID: 8231234 DOI: 10.1016/0145-2126(93)90040-r] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
B-CLL is a malignant monoclonal B-cell disorder and B-MLUS is the benign counterpart. The proliferative response and the capacity to secrete IgM was measured in B-CLL and B-MLUS, respectively, and compared to normal B-cells. SAC and a mAb against CD40 were used as stimulatory agents. No cell population responded to anti-CD40 mAb alone. SAC only induced a high DNA synthesis rate in normal B-cells as well as in B-CLL cells, although the magnitude was three-fold lower and delayed for about 48 h in B-CLL. B-MLUS cells did not proliferate in response to SAC. The combination of anti-CD40 and SAC enhanced the proliferative capacity of normal B-cells and produced a more rapid response in B-CLL. B-MLUS cells were not activated. Normal B-cells and B-MLUS did not secrete IgM after SAC stimulation, while B-CLL cells had a continuous increase in the IgM production during a 6-day culture period. The higher proliferative capacity of B-CLL cells compared with B-MLUS cells may be explained by an increased expression of activation molecules e.g. receptors for various cytokines and growth factors. Moreover, the inertness and inability of B-MLUS cells in comparison to normal B- and B-CLL cells to respond to powerful activation signals might indicate an intrinsic defect of B-MLUS cells in the signal transduction leading to a block of mitosis and a benign course of the disease.
Collapse
Affiliation(s)
- C A Garcia
- Department of Biology, Instituto Nacional de Oncologia y Radiobiologia, Habana, Cuba
| | | | | | | | | |
Collapse
|
9
|
Garrett LR, Coder DM, McDougall JK. Increased intracellular calcium is associated with progression of HPV-18 immortalized human keratinocytes to tumorigenicity. Cell Calcium 1991; 12:343-9. [PMID: 1654210 DOI: 10.1016/0143-4160(91)90050-o] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Studies were conducted using normal and human papillomavirus Type 18 (HPV-18) immortalized human keratinocytes to assess possible alterations in the differentiation process as a consequence of increased intracellular calcium concentration. Normal keratinocytes exposed to increased extracellular calcium or the phorbol ester TPA, exhibited terminal differentiation characteristics. However, late passage HPV-18 immortalized keratinocytes (designated FEP-1811) were resistant to such terminal differentiation signals. Flow cytometric analyses of 1811 cells at various stages of passage in culture revealed progressively higher levels of intracellular calcium in the immortalized cells with passage in culture when compared to normal, primary keratinocytes. Furthermore, 1811 cells isolated from tumors which developed in irradiated nude mice contained the highest level of intracellular calcium of all the cells examined. These results suggest that an increase in the concentration of intracellular calcium is associated with progression of HPV-18 immortalized keratinocytes to tumorigenicity.
Collapse
Affiliation(s)
- L R Garrett
- Fred Hutchinson Cancer Research Center, Seattle, Washington
| | | | | |
Collapse
|
10
|
Brunswick M, Samelson LE, Mond JJ. Surface immunoglobulin crosslinking activates a tyrosine kinase pathway in B cells that is independent of protein kinase C. Proc Natl Acad Sci U S A 1991; 88:1311-4. [PMID: 1705033 PMCID: PMC51007 DOI: 10.1073/pnas.88.4.1311] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
It has been found that the principal biochemical pathway activated in B cells stimulated by antigen- or anti-immunoglobulin-mediated crosslinking of surface immunoglobulin is that resulting in hydrolysis of phosphatidylinositol bisphosphate with generation of diacylglycerol and inositol trisphosphate. Recent evidence suggests that surface immunoglobulin-mediated B-cell activation can proceed without detectable increases in the concentration of either diacylglycerol or intracellular Ca2+ concentration, implicating involvement of other non-protein-kinase-C/Ca2(+)-dependent signal-transduction pathways. Therefore, we sought evidence for activation of a signaling pathway that is associated with growth regulation in other cell types--i.e., the protein-tyrosine kinases. We now show that crosslinking of membrane immunoglobulin by mitogenic antibodies leads to rapid tyrosine phosphorylation of several cellular substrates, consistent with the induction of a tyrosine kinase activity. This increase in tyrosine phosphorylation is weakly (if at all) stimulated by other B-cell mitogens, including phorbol esters and ionophores, and does not require the presence of detectable protein kinase C. Furthermore, inhibition of anti-immunoglobulin-stimulated phosphatidylinositol bisphosphate hydrolysis does not inhibit activation of this tyrosine kinase-dependent pathway. These findings suggest that occupancy of the membrane immunoglobulin receptor may induce multiple pathways of activation.
Collapse
Affiliation(s)
- M Brunswick
- Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799
| | | | | |
Collapse
|
11
|
Levy Y, Fermand JP, Brouet JC. Differential effects of low and high concentrations of interleukin 6 on human B cells. Eur J Immunol 1990; 20:2389-93. [PMID: 2147647 DOI: 10.1002/eji.1830201105] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In this report we have studied the functional effects of a wide range of interleukin 6 concentrations on human B cells. B cells purified from tonsils and from five of six spleens proliferated directly in a dose-dependent manner in the presence of low concentrations (1-100 pg/ml) of IL 6 whereas B cells from the sixth spleen proliferated only after in vitro anti-mu antibodies activation. Only large B cells (presumably in vivo activated B cells) were responsive to IL 6. High concentrations of IL 6 (1-10 ng/ml) did not trigger B cell proliferation but were able to up-regulate the expression of the B5 activation antigen on B cells, whereas the expression of two other B cell antigens (CD20 and CD23) was unchanged. At all concentrations of IL 6 tested (0.01-10 ng/ml) no B cell differentiation occurred after 7 days culture. Depletion before culture of B5+ cells from the B cell-enriched spleen cell preparation abolished both the proliferative effect and up-regulation of B5 antigen induced by IL 6, indicating that this lymphokine acted primarily on activated B cells. This differential effect of "low" and "high" concentrations of IL 6 on activated B cells may solve controversy on the role of IL 6 as an early or late agent in B cell maturation.
Collapse
Affiliation(s)
- Y Levy
- Laboratory of Immunochemistry and Immunopathology, INSERM U 108, Hôpital Saint-Louis, Paris, France
| | | | | |
Collapse
|
12
|
Rehe GT, Katona IM, Brunswick M, Wahl LM, June CH, Mond JJ. Activation of human B lymphocytes by nanogram concentrations of anti-IgM-dextran conjugates. Eur J Immunol 1990; 20:1837-42. [PMID: 1698635 DOI: 10.1002/eji.1830200831] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Surface immunoglobulin (sIg) cross-linking on B lymphocytes by high concentrations of anti-Ig antibody has been used to mimic antigen-stimulated B cell activation. In order to develop a system to study sIg-mediated T cell-independent B cell activation using low concentrations of anti-Ig antibody that more closely resemble the concentrations of antigen that are achieved under in vivo conditions, we conjugated monoclonal anti-human IgM antibody (anti-mu) to dextran (molecular weight 2 X 10(6)) thereby increasing its valency. This dextran conjugate (anti-mu-Dex) stimulated comparable levels of thymidine incorporation and B cell size increases as were seen with unconjugated anti-mu but at 100- to 1000-fold lower concentrations. Anti-mu-Dex also stimulated increases in intracellular ionized calcium ([Ca2+]i) in a higher percentage of cells, of greater magnitude and of longer duration than that stimulated by unconjugated anti-mu. Interestingly, there was no direct correlation between the increases in [Ca2+]i that were stimulated by anti-mu-Dex and its ability to stimulate B cell proliferation. The concentrations of anti-mu-Dex (10 micrograms/ml) that led to the highest increase in [Ca2+]i resulted in thymidine incorporation that was no greater than that of medium control, whereas 0.01 to 0.1 microgram/ml stimulated significant thymidine incorporation with 50% lower levels of stimulation of [Ca2+]i. These data demonstrate that anti-mu-Dex is a potent activator of human B lymphocytes, is effective even at ng/ml concentrations which over a 2-h time period do not induce detectable modulation of sIg, and its stimulation of B cells into G1 and S may not be directly related to its ability to stimulate increases in levels of [Ca2+]i.
Collapse
Affiliation(s)
- G T Rehe
- Department of Medicine, Walter Reed Army Medical Center, Washington
| | | | | | | | | | | |
Collapse
|
13
|
Sarthou P, Henry-Toulmé N, Cazenave PA. Membrane IgM cross-linking is not coupled to protein kinase C translocation in WEHI-231 B lymphoma cells. Eur J Immunol 1989; 19:1247-52. [PMID: 2668012 DOI: 10.1002/eji.1830190715] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The early molecular events involved in the process of signal transduction via membrane immunoglobulins (mIg) include phosphatidyl inositol metabolism, intracellular Ca2+ mobilization, and protein kinase C (PKC) activation. Anti-mIg antibodies exert either stimulating or inhibitory effects depending on the activation state and/or the differentiation stage of B cells. WEHI-231 is a murine B lymphoma that becomes inactivated upon anti-mIg treatment. This lymphoma has an immature B cell phenotype and is considered as a model for tolerance induction in B lymphocytes. In this study, we have investigated the relationship between mIg triggering, Ca2+ elevation, PKC translocation, and growth inhibition in WEHI-231 cells. Monoclonal antibodies to mu and kappa chains of the mIgM receptor promoted a rapid increase in intracytoplasmic Ca2+ and were potent inhibitors of cell growth. Ca2+ elevation and PKC translocation have been previously shown to be associated in B lymphocytes. To study the subcellular distribution of PKC in WEHI-231 cells, we used enzymatic assays and immunodetection methods. Although phorbol 12-myristate 13-acetate induced a rapid and almost complete redistribution of cytosolic PKC to the membrane fraction, anti-mIg treatment failed to modify the compartmentalization of PKC. These findings extend recent observations suggesting that B cell triggering through mIg receptors may involve additional pathways independent from PKC activation. PKC activation in normal B cells is also believed to provide a regulatory signal which limits the magnitude of the early signals produced by anti-mIg. Such a regulatory control is unlikely in WEHI-231 cells, due to the dissociation between Ca2+ mobilization and PKC translocation. Our findings therefore suggest that the sensitivity of immature B cells such as WEHI-231 to the inhibitory effects of anti-mIg antibodies may result in part from alterations of the phosphoinositide signal transduction pathway.
Collapse
Affiliation(s)
- P Sarthou
- Unité d'Immunochimie Analytique, Département d'Immunologie, Institut Pasteur, Paris, France
| | | | | |
Collapse
|
14
|
Mooney N, Grillot-Courvalin C, Hivroz C, Charron D. A role for MHC class II antigens in B-cell activation. J Autoimmun 1989; 2 Suppl:215-23. [PMID: 2789060 DOI: 10.1016/0896-8411(89)90133-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Class II antigens of the major histocompatibility complex (MHC) have a well-defined role in restricting cellular interactions and presenting processed antigen to T cells. In addition, a fundamental role for Class II antigens in cellular activation has been suggested, following studies demonstrating that Class II antigen binding alters the proliferation of various cell types. This is further supported by biochemical evidence of signal transduction by second messengers after ligation of the Class II antigens. We have investigated the role of HLA Class II antigens in the activation of B cells. Both activated and resting B cells proliferate in the presence of Sepharose--conjugated anti-Class II antibodies. This proliferation was not epitope-restricted and was unaffected by low m.w. BCGF. Intracellular free calcium elevation was also examined as a marker of cellular activation. (Ca2+)i was increased after the binding and cross-linking of an anti-DR antibody. The above results further support the role of Class II antigens as signal-transducing molecules.
Collapse
Affiliation(s)
- N Mooney
- Laboratoire d'Immunogénétique Moléculaire, Institut Biomédical des Cordeliers, Paris; France
| | | | | | | |
Collapse
|