1
|
Furusawa Y, Kaneko MK, Kato Y. Establishment of C 20Mab-11, a novel anti-CD20 monoclonal antibody, for the detection of B cells. Oncol Lett 2020; 20:1961-1967. [PMID: 32724441 PMCID: PMC7377059 DOI: 10.3892/ol.2020.11753] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 03/02/2020] [Indexed: 12/19/2022] Open
Abstract
CD20 is one of several B-lymphocyte antigens that has been shown to be an effective target for the detection and treatment of B-cell lymphomas. Sensitive and specific monoclonal antibodies (mAbs) are required for every application used for the diagnosis of B-cell lymphoma. Although many anti-CD20 mAbs have been established, the types of applications, those anti-CD20 can be used in, are limited. In this study, we aimed to establish novel anti-CD20 mAbs to be used for broad applications, such as flow cytometry, western blot, and immunohistochemical analyses, using the Cell-Based Immunization and Screening (CBIS) method. One of the established mAbs, C20Mab-11 (IgM, kappa), detected overexpression of CD20 in CHO-K1 or LN229 cell lines, indicating that C20Mab-11 is specific for CD20. In western blot analyses, C20Mab-11 detected not only overexpression of CD20 in CHO-K1 or LN229 cell lines, but also CD20 of BALL-1 and Raji cells with both sensitivity and specificity. Furthermore, C20Mab-11 strongly stained B cells of the lymph follicle and B cell lymphomas in immunohistochemical analyses. These results indicate that C20Mab-11 develped by CBIS method, is useful for the detection of CD20 in lymphoma tissues by flow cytometry, western blot, and immunohistochemical analyses and potentially could be beneficial for the treatment of B cell lymphomas.
Collapse
Affiliation(s)
- Yoshikazu Furusawa
- Department of Antibody Drug Development, Tohoku University Graduate School of Medicine, Sendai, Miyagi 980-8575, Japan.,New Industry Creation Hatchery Center, Tohoku University, Sendai, Miyagi 980-8575, Japan
| | - Mika Kato Kaneko
- Department of Antibody Drug Development, Tohoku University Graduate School of Medicine, Sendai, Miyagi 980-8575, Japan
| | - Yukinari Kato
- Department of Antibody Drug Development, Tohoku University Graduate School of Medicine, Sendai, Miyagi 980-8575, Japan.,New Industry Creation Hatchery Center, Tohoku University, Sendai, Miyagi 980-8575, Japan
| |
Collapse
|
2
|
Bagacean C, Zdrenghea M, Tempescul A, Cristea V, Renaudineau Y. Anti-CD20 monoclonal antibodies in chronic lymphocytic leukemia: from uncertainties to promises. Immunotherapy 2017; 8:569-81. [PMID: 27140410 DOI: 10.2217/imt-2015-0015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Over the last two decades, anti-CD20 monoclonal antibody (mAb) therapy has improved patient outcome in B-cell malignancies, and confirmed CD20 as an important target in chronic lymphocytic leukemia (CLL). Until recently, the gold standard was based on the utilization of rituximab combined with chemotherapy (fludarabine and cyclophosphamide), but patients often relapse. Next, with our better understanding of mAb engineering, anti-CD20 mAb therapy has evolved with the development of new mAb permitting significant clinical responses by improving pharmacokinetics, safety, activity and immunogenicity. Last but not least, the development of key tumoral tyrosine kinase inhibitors and their association with anti-CD20 mAb is a work in progress with promising results.
Collapse
Affiliation(s)
- Cristina Bagacean
- Research Unit INSERM ESPRI, ERI29/EA2216 Immunotherapy & B Cell Diseases, Réseau épigénétique et Réseau canaux ioniques du Cancéropôle Grand Ouest, Labex IGO, European University of Brittany, Brest, France.,'Iuliu Hatieganu' University of Medicine & Pharmacy, 8 Babes Street, 400012, Cluj-Napoca, Romania
| | - Mihnea Zdrenghea
- 'Iuliu Hatieganu' University of Medicine & Pharmacy, 8 Babes Street, 400012, Cluj-Napoca, Romania.,'Ion Chiricuta' Institute of Oncology, 34-36 Republicii Street, 400015 Cluj-Napoca, Romania
| | - Adrian Tempescul
- Research Unit INSERM ESPRI, ERI29/EA2216 Immunotherapy & B Cell Diseases, Réseau épigénétique et Réseau canaux ioniques du Cancéropôle Grand Ouest, Labex IGO, European University of Brittany, Brest, France.,Department of Hematology, CHRU Morvan, Brest, France
| | - Victor Cristea
- 'Iuliu Hatieganu' University of Medicine & Pharmacy, 8 Babes Street, 400012, Cluj-Napoca, Romania
| | - Yves Renaudineau
- Research Unit INSERM ESPRI, ERI29/EA2216 Immunotherapy & B Cell Diseases, Réseau épigénétique et Réseau canaux ioniques du Cancéropôle Grand Ouest, Labex IGO, European University of Brittany, Brest, France.,Laboratory of Immunology & Immunotherapy, CHRU Morvan, Brest, France
| |
Collapse
|
3
|
A molecular perspective on rituximab: A monoclonal antibody for B cell non Hodgkin lymphoma and other affections. Crit Rev Oncol Hematol 2015; 97:275-90. [PMID: 26443686 DOI: 10.1016/j.critrevonc.2015.09.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 08/04/2015] [Accepted: 09/24/2015] [Indexed: 12/20/2022] Open
Abstract
Rituximab (a chimeric anti-CD20 monoclonal antibody) is the first Food and Drug Administration approved anti-tumor antibody. Immunotherapy by rituximab, especially in combination-therapy, is a mainstay for a vast variety of B-cell malignancies therapy. Its therapeutic value is unquestionable, yet the mechanisms of action responsible for anti-tumor activity of rituximab and rituximab resistance mechanisms are not completely understood. Investigation of the mechanisms of action that contribute to the rituximab activity have eventually directed to a suite of novel combinations and novel treatment schedules, and also have resulted new generations of antibodies with more desired effects. Although, further investigations are needed to define the mechanisms of rituximab resistance and prominent effector activity of the altered next generation anti-CD20 to improve their efficacies and develop new anti-CD20 monoclonal antibodies in NHL treatment. This article focuses on the properties of CD20 which led scientists to select it as an effective therapeutic target and the molecular details of mechanisms of rituximab action and resistance. We also discuss about the impact of rituximab in monotherapy and in combination with chemotherapy regimens. Finally, we comparatively summarize the next generations of anti CD20 monoclonal antibodies to highlight their advantages relative to their ancestor: Rituximab.
Collapse
|
4
|
Hussain RZ, Hayardeny L, Cravens PC, Yarovinsky F, Eagar TN, Arellano B, Deason K, Castro-Rojas C, Stüve O. Immune surveillance of the central nervous system in multiple sclerosis--relevance for therapy and experimental models. J Neuroimmunol 2014; 276:9-17. [PMID: 25282087 PMCID: PMC4301841 DOI: 10.1016/j.jneuroim.2014.08.622] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 08/15/2014] [Accepted: 08/20/2014] [Indexed: 12/25/2022]
Abstract
Treatment of central nervous system (CNS) autoimmune disorders frequently involves the reduction, or depletion of immune-competent cells. Alternatively, immune cells are being sequestered away from the target organ by interfering with their movement from secondary lymphoid organs, or their migration into tissues. These therapeutic strategies have been successful in multiple sclerosis (MS), the most prevalent autoimmune inflammatory disorder of the CNS. However, many of the agents that are currently approved or in clinical development also have severe potential adverse effects that stem from the very mechanisms that mediate their beneficial effects by interfering with CNS immune surveillance. This review will outline the main cellular components of the innate and adaptive immune system that participate in host defense and maintain immune surveillance of the CNS. Their pathogenic role in MS and its animal model experimental autoimmune encephalomyelitis (EAE) is also discussed. Furthermore, an experimental model is introduced that may assist in evaluating the effect of therapeutic interventions on leukocyte homeostasis and function within the CNS. This model or similar models may become a useful tool in the repertoire of pre-clinical tests of pharmacological agents to better explore their potential for adverse events.
Collapse
Affiliation(s)
- Rehana Z Hussain
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center at Dallas, TX, USA
| | | | - Petra C Cravens
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center at Dallas, TX, USA
| | - Felix Yarovinsky
- Department of Immunology, University of Texas Southwestern Medical Center at Dallas, TX, USA
| | - Todd N Eagar
- Histocompatibility and Transplant Immunology, Department of Pathology and Genomic Medicine, The Methodist Hospital Physician Organization, Houston, TX, USA
| | - Benjamine Arellano
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center at Dallas, TX, USA
| | - Krystin Deason
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center at Dallas, TX, USA
| | - Cyd Castro-Rojas
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center at Dallas, TX, USA
| | - Olaf Stüve
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center at Dallas, TX, USA; Neurology Section, VA North Texas Health Care System, Medical Service, Dallas, TX, USA; Department of Neurology, Klinikum rechts der Isar, Technische Universität München, Germany.
| |
Collapse
|
5
|
Kopeček J. Polymer-drug conjugates: origins, progress to date and future directions. Adv Drug Deliv Rev 2013; 65:49-59. [PMID: 23123294 DOI: 10.1016/j.addr.2012.10.014] [Citation(s) in RCA: 259] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Revised: 09/28/2012] [Accepted: 10/01/2012] [Indexed: 01/01/2023]
Abstract
This overview focuses on bioconjugates of water-soluble polymers with low molecular weight drugs and proteins. After a short discussion of the origins of the field, the state-of-the-art is reviewed. Then research directions needed for the acceleration of the translation of nanomedicines into the clinic are outlined. Two most important directions, synthesis of backbone degradable polymer carriers and drug-free macromolecular therapeutics, a new paradigm in drug delivery, are discussed in detail. Finally, the future perspectives of the field are briefly discussed.
Collapse
|
6
|
Wu K, Yang J, Liu J, Kopeček J. Coiled-coil based drug-free macromolecular therapeutics: in vivo efficacy. J Control Release 2011; 157:126-31. [PMID: 21843563 DOI: 10.1016/j.jconrel.2011.08.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 06/25/2011] [Accepted: 08/03/2011] [Indexed: 10/17/2022]
Abstract
We evaluated a new concept in cancer therapy, coiled-coil mediated induction of apoptosis in Raji B cells, for treatment of human B-cell lymphoma in a preclinical animal model. The system is composed of a pair of complementary coiled-coil peptides, CCE and CCK, forming antiparallel heterodimers; Fab' fragment of the 1F5 anti-CD20 antibody; and N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer. One peptide is conjugated to the Fab' fragment (Fab'-CCE), the other is conjugated in multiple grafts to polyHPMA (CCK-P; P is the HPMA copolymer backbone). Intravenous administration of Fab'-CCE conjugate, followed by the administration of CCK-P produced long-term survivors in SCID (C.B.-17) mice bearing human B-lymphoma xenografts. The rationale of the design is the absence of low molecular weight drugs and the fact that crosslinking of CD20 at B-cell surface results in apoptosis. This approach creates a new paradigm for manipulating molecular recognition principles in the design of improved cancer treatment.
Collapse
Affiliation(s)
- Kuangshi Wu
- Department of Pharmaceutics and Pharmaceutical Chemistry/CCCD, University of Utah, Salt Lake City, UT 84112, USA
| | | | | | | |
Collapse
|
7
|
Kreindler D, Petsche D, Hrincu A, Gougos A, Quackenbush EJ, Freedman MH, Gelfand EW, Letarte M. Quantitative Phenotyping of Childhood Leukemia Identifies Variable and Invariable Cell Surface Antigens. Leuk Lymphoma 2009; 3:7-18. [DOI: 10.3109/10428199009050970] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
8
|
Johnson RN, Kopecková P, Kopecek J. Synthesis and evaluation of multivalent branched HPMA copolymer-Fab' conjugates targeted to the B-cell antigen CD20. Bioconjug Chem 2009; 20:129-37. [PMID: 19154157 DOI: 10.1021/bc800351m] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Several drug delivery designs combine synthetic drug carriers with covalently conjugated targeting moieties. Such modifications of monoclonal antibodies (mAb), or their Fab' fragments, inevitably result in diminished affinity for their targeted tissue. In an attempt to overcome this limitation, high molecular weight, branched N-(2-hydroxypropyl)methacrylamide (HPMA) copolymers were synthesized and conjugated with Fab' fragments of the anti-CD20 antibody, 1F5. This produced multivalent conjugates with varying valency (amount of Fab' per macromolecule) targeted to the B-cell antigen CD20. Evaluation of a multivalent effect was done by determining the apparent K(D) at low concentrations of conjugates, the Sips heterogeneity factor, a, and the binding enhancement factors of each construct. The results clearly indicated that multivalency could improve the affinity of the HPMA copolymer-Fab' conjugates to that of unconjugated mAb.
Collapse
Affiliation(s)
- Russell N Johnson
- Departments of Bioengineering, and Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
| | | | | |
Collapse
|
9
|
|
10
|
Siffrin V, Brandt AU, Herz J, Zipp F. New insights into adaptive immunity in chronic neuroinflammation. Adv Immunol 2007; 96:1-40. [PMID: 17981203 DOI: 10.1016/s0065-2776(07)96001-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Understanding the immune response in the central nervous system (CNS) is crucial for the development of new therapeutic concepts in chronic neuroinflammation, which differs considerably from other autoimmune diseases. Special immunologic properties of inflammatory processes in the CNS, which is often referred to as an immune privileged site, imply distinct features of CNS autoimmune disease in terms of disease initiation, perpetuation, and therapeutic accessibility. Furthermore, the CNS is a stress-sensitive organ with a low capacity for self-renewal and is highly prone to bystander damage caused by CNS inflammation. This leads to neuronal degeneration that contributes considerably to the phenotype of the disease. In this chapter, we discuss recent findings emphasizing the predominant role of the adaptive immune system in the pathogenesis of chronic neuroinflammation, that is, multiple sclerosis (MS) in patients and experimental autoimmune encephalomyelitis (EAE) in rodents. In addition, we report on efforts to translate these findings into clinical practice with the aim of developing selective treatment regimens.
Collapse
Affiliation(s)
- Volker Siffrin
- Cecilie-Vogt-Clinic for Molecular Neurology, Charité-Universitaetsmedizin Berlin, 10117 Berlin, Germany
| | | | | | | |
Collapse
|
11
|
Jubala CM, Wojcieszyn JW, Valli VEO, Getzy DM, Fosmire SP, Coffey D, Bellgrau D, Modiano JF. CD20 expression in normal canine B cells and in canine non-Hodgkin lymphoma. Vet Pathol 2005; 42:468-76. [PMID: 16006606 DOI: 10.1354/vp.42-4-468] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We examined the expression of CD20 in normal canine peripheral blood mononuclear cells, normal canine spleen, and canine non-Hodgkin lymphoma (NHL) to determine the feasibility of using this antigen as a diagnostic aid and as a possible target for therapy. An antibody generated against a C-terminal (intracytoplasmic) epitope of human CD20 recognized proteins of 32-36 kd in normal and malignant canine lymphocytes. This antibody showed restricted membrane binding in a subset of lymphocytes in peripheral blood, in the B-cell regions from a normal canine spleen and lymph node, and in malignant cells from 19 dogs with B-cell NHL, but not from 15 dogs with T-cell NHL. The patterns of CD20 reactivity in these samples overlapped those seen using an antibody that recognizes canine CD79a. This anti-CD20 antibody is therefore suitable as an aid to phenotype canine NHL. In contrast, normal canine B cells were not recognized by any of 28 antibodies directed against the extracellular domains of human CD20 (including the chimeric mouse-human antibody Rituximab) or by any of 12 antibodies directed against the extracellular domains of mouse CD20. Thus, the use of CD20 as a therapeutic target will require the generation of specific antibodies against the extracellular domains of canine CD20.
Collapse
Affiliation(s)
- C M Jubala
- Integrated Department of Immunology, AMC Cancer Center, University of Colorado Health Sciences Center, 1600 Pierce Street, 2-Diamond Research Building, Denver, CO 80214, USA
| | | | | | | | | | | | | | | |
Collapse
|
12
|
Jazirehi AR, Bonavida B. Cellular and molecular signal transduction pathways modulated by rituximab (rituxan, anti-CD20 mAb) in non-Hodgkin's lymphoma: implications in chemosensitization and therapeutic intervention. Oncogene 2005; 24:2121-43. [PMID: 15789036 DOI: 10.1038/sj.onc.1208349] [Citation(s) in RCA: 191] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The clinical application of rituximab (chimeric mouse anti-human CD20 mAb, Rituxan, IDEC-C2B8), alone and/or combined with chemotherapy, has significantly ameliorated the treatment outcome of patients with relapsed and refractory low-grade or follicular non-Hodgkin's lymphoma (NHL). The exact in vivo mechanisms of action of rituximab are not fully understood, although antibody-dependent cell-mediated cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC), and apoptosis have been suggested. We have proposed that modifications of the cellular signaling pathways by rituximab may be crucial for its clinical response. The B-cell restricted cell surface phosphoprotein CD20 is involved in many cellular signaling events including proliferation, activation, differentiation, and apoptosis upon crosslinking. Monomeric rituximab chemosensitizes drug-resistant NHL cells via selective downregulation of antiapoptotic factors through the type II mitochondrial apoptotic pathway. Several signaling pathways are affected by rituximab which are implicated in the underlying molecular mechanisms of chemosensitization. ARL (acquired immunodeficiency syndrome (AIDS)-related lymphoma) and non-ARL cell lines have been examined as in vitro model systems. In ARL, rituximab diminishes the activity of the p38MAPK signaling pathway resulting in inhibition of the interleukin (IL)-10/IL-10R autocrine/paracrine cytokine autoregulatory loop leading to the inhibition of constitutive STAT-3 activity and subsequent downregulation of Bcl-2 expression leading to chemosensitization. Rituximab upregulates Raf-1 kinase inhibitor protein (RKIP) expression in non-ARL cells. Through physical association with Raf-1 and nuclear factor kappaB (NF-kappa B)-inducing kinase (NIK), RKIP negatively regulates two major survival pathways, namely, the extracellular signal-regulated kinase1/2 (ERK1/2) and the NF-kappa B pathways, respectively. Downmodulation of the ERK1/2 and NF-kappa B pathways inhibits the transcriptional activity of AP-1 and NF-kappa B transcription factors, respectively, both of which lead to the downregulation of Bcl-(xL) (Bcl-2 related gene (long alternatively spliced variant of Bcl-x gene)) transcription and expression and sensitization to drug-induced apoptosis. Bcl-(xL)-overexpressing cells corroborated the pivotal role of Bcl-(xL) in chemosensitization. The specificity of rituximab-mediated signaling and functional effects were corroborated by the use of specific pharmacological inhibitors. Many patients do not respond and/or relapse and the mechanisms of unresponsiveness are unknown. Rituximab-resistant B-NHL clones were generated to investigate the acquired resistance to rituximab-mediated signaling, and chemosensitization. Resistant clones display different phenotypic, genetic and functional properties compared to wild-type cells. This review summarizes the data highlighting a novel role of rituximab as a signal-inducing antibody and as a chemosensitizing agent through negative regulation of major survival pathways. Studies presented herein also reveal several intracellular targets modified by rituximab, which can be exploited for therapeutic and prognostic purposes in the treatment of patients with rituximab- and drug-refractory NHL.
Collapse
Affiliation(s)
- Ali R Jazirehi
- Department of Microbiology, Immunology and Molecular Genetics, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA 90095-1747, USA
| | | |
Collapse
|
13
|
Roberts WK, Livingston PO, Agus DB, Pinilla-Ibarz J, Zelenetz A, Scheinberg DA. Vaccination with CD20 peptides induces a biologically active, specific immune response in mice. Blood 2002; 99:3748-55. [PMID: 11986232 DOI: 10.1182/blood.v99.10.3748] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
CD20 is a 33-kD B-cell antigen that is expressed from the early pre-B-cell stage of development and is lost on differentiation of B cells into plasma cells. Because CD20 is expressed strictly by B cells, it is an attractive target for B-cell lymphoma therapy. Monoclonal antibodies to CD20 have been used successfully in the treatment of B-cell lymphomas. We hypothesized that a vaccine consisting of CD20 peptide sequences might be capable of inducing an active, specific, humoral immune response to the protein. Vaccine therapy would have the advantage of generating a polyclonal response to the antigen in contrast to the monoclonal response of an infused antibody. Balb/c mice were vaccinated with prototype vaccine constructs that consisted of peptides representing the human or mouse CD20 extracellular sequences conjugated to carrier proteins and mixed with QS21 adjuvant. Sera from the vaccinated mice demonstrated high-titer, specific antibodies to various epitopes on the immunizing peptides in enzyme-linked immunosorbent assay, weaker antibody binding to native CD20 on cells by flow cytometry, and antibody-mediated complement killing of CD20(+) cells in some cases. Specific proliferation and secretion of interleukin 4 and interferon gamma by mouse spleen cells in response to the immunizing peptides were also demonstrated. Mice vaccinated with the CD20 peptide keyhole limpet hemocyanin conjugates had a 25% decrease in CD19(+) splenic B cells relative to control mice. These data indicate that a biologically active, specific immune response to CD20 can be elicited in mice vaccinated with CD20 peptide conjugates.
Collapse
Affiliation(s)
- Wendy K Roberts
- Department of Molecular Pharmacology and Chemistry, Weill Graduate School of Medical Sciences of Cornell University, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
| | | | | | | | | | | |
Collapse
|
14
|
Pedersen IM, Buhl AM, Klausen P, Geisler CH, Jurlander J. The chimeric anti-CD20 antibody rituximab induces apoptosis in B-cell chronic lymphocytic leukemia cells through a p38 mitogen activated protein-kinase-dependent mechanism. Blood 2002; 99:1314-9. [PMID: 11830481 DOI: 10.1182/blood.v99.4.1314] [Citation(s) in RCA: 162] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Antibodies against CD20 can activate complement and induce antibody-dependent cellular cytotoxicity (ADCC) in B lymphocytes. In B-cell lines, such antibodies also induce apoptosis. In this study, the expression and function of CD20 on B-cell chronic lymphocytic leukemia (B-CLL) cells were analyzed. Flow cytometric analysis demonstrated that B-CLL cells express CD20 with a fluorescence intensity that is significantly weaker than that of normal CD5(+) and CD5(-) B cells and that of malignant CD5(-) low-grade non-Hodgkin lymphoma cells. A small population of cells from healthy donors that have an expression pattern of CD5 and CD20 identical to that of B-CLL cells were identified, and this population was confirmed to be of T lineage, not B lineage. Culture of freshly isolated B-CLL cells in the presence of the chimeric anti-CD20 antibody rituximab and a cross-linking F(ab)(2) fragment, resulted in dose- and time-dependent induction of apoptosis. The induction of apoptosis occurred under conditions in which the influence of complement activation and ADCC was negligible. Cross-linking of rituximab induced strong and sustained phosphorylation of the 3 mitogen activated protein (MAP) kinases c-Jun NH2-terminal protein kinase, extracellular signal-regulated kinase, and p38. Introduction of the p38 inhibitor SB203580 into the system completely blocked signaling downstream of p38, as evidenced by the absence of MAPKAP K2 activity, and significantly reduced the degree of anti-CD20-induced apoptosis. These results demonstrate that cross-linking of rituximab bound to CD20 on freshly isolated B-CLL cells induces apoptosis through a signaling pathway that is dependent on p38 MAP-kinase activation.
Collapse
MESH Headings
- Antibodies, Monoclonal/pharmacology
- Antibodies, Monoclonal/therapeutic use
- Antibodies, Monoclonal, Murine-Derived
- Antigens, CD20/immunology
- Antigens, CD20/metabolism
- Antigens, CD20/physiology
- Antineoplastic Agents/pharmacology
- Antineoplastic Agents/therapeutic use
- Apoptosis/drug effects
- Enzyme Activation
- Humans
- Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy
- Leukemia, Lymphocytic, Chronic, B-Cell/enzymology
- Leukemia, Lymphocytic, Chronic, B-Cell/pathology
- MAP Kinase Signaling System
- Mitogen-Activated Protein Kinases/metabolism
- Mitogen-Activated Protein Kinases/physiology
- Phosphorylation
- Rituximab
- Tumor Cells, Cultured/drug effects
- p38 Mitogen-Activated Protein Kinases
Collapse
Affiliation(s)
- Irene Munk Pedersen
- Leukemia Laboratory, Department of Hematology, The Finsen Centre, Rigshospitalet, Copenhagen, Denmark
| | | | | | | | | |
Collapse
|
15
|
Leuker CE, Labow M, Müller W, Wagner N. Neonatally induced inactivation of the vascular cell adhesion molecule 1 gene impairs B cell localization and T cell-dependent humoral immune response. J Exp Med 2001; 193:755-68. [PMID: 11257141 PMCID: PMC2193422 DOI: 10.1084/jem.193.6.755] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Vascular cellular adhesion molecule (VCAM)-1 is a membrane-bound cellular adhesion molecule that mediates adhesive interactions between hematopoietic progenitor cells and stromal cells in the bone marrow (BM) and between leukocytes and endothelial as well as dendritic cells. Since VCAM-1-deficient mice die embryonically, conditional VCAM-1 mutant mice were generated to analyze the in vivo function of this adhesion molecule. Here we show that interferon-induced Cre-loxP-mediated deletion of the VCAM-1 gene after birth efficiently ablates expression of VCAM-1 in most tissues like, for example, BM, lymphoid organs, and lung, but not in brain. Induced VCAM-1 deficiency leads to a reduction of immature B cells in the BM and to an increase of these cells in peripheral blood but not in lymphoid organs. Mature recirculating B cells are reduced in the BM. In a migration assay, the number of mature B cells that appears in the BM after intravenous injection is decreased. In addition, the humoral immune response to a T cell-dependent antigen is impaired. VCAM-1 serves an important role for B cell localization and the T cell-dependent humoral immune response.
Collapse
Affiliation(s)
| | - Mark Labow
- Department of Functional Genomics, Novartis Pharmaceuticals, Incorporated, Summit, New Jersey 07901
| | - Werner Müller
- Institute for Genetics, University of Cologne, D-50931 Cologne, Germany
| | - Norbert Wagner
- Institute for Genetics, University of Cologne, D-50931 Cologne, Germany
- Department of Pediatrics, University of Bonn, D-53113 Bonn, Germany
| |
Collapse
|
16
|
Abstract
Engagement of MHC class II and CD40 on B cell lines triggers intracellular signals that activates cell surface adhesion receptors, resulting in LFA-1-dependent and -independent cell-cell adhesion. In this study, a murine monoclonal antibody (mAb R21) has been produced against a LFA-1-negative human B cell line and proven to completely block MHC class II- and CD40-induced LFA-1-independent homotypic adhesion. However, this mAb failed to prevent MHC class II- or CD40-induced homotypic adhesion in LFA-1-positive Raji B cells, and alone, it triggered LFA-1-dependent cell-cell adhesion. Biochemical characterization indicated that the CD20 molecule, a tetraspan phosphoprotein expressed on B cells that functions as a Ca2+-conductive ion channel, is the target of mAb R21. Interestingly, further biochemical analysis demonstrated that CD20 is physically associated with MHC class II and CD40 molecules on the cell surface of LFA-1-negative and LFA-1-positive B cell lines. Although these three molecules are associated with each other, the complex formation between any two of them is not dependent on the simultaneous expression of the three molecules. Altogether, these results indicate that CD20 is physically and probably functionally coupled to the MHC class II and CD40 molecules; thereby it may have certain modulatory effects on their functions.
Collapse
Affiliation(s)
- C Léveillé
- Centre de Recherche en Rhumatologie et Immunologie, CHUL, St-Foy, Québec, Canada
| | | | | |
Collapse
|
17
|
Polyak MJ, Tailor SH, Deans JP. Identification of a Cytoplasmic Region of CD20 Required for Its Redistribution to a Detergent-Insoluble Membrane Compartment. THE JOURNAL OF IMMUNOLOGY 1998. [DOI: 10.4049/jimmunol.161.7.3242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
CD20 is a B lymphocyte integral membrane protein with signal-transducing properties. Abs directed toward extracellular CD20 epitopes activate nonreceptor tyrosine kinases and modulate cell cycle progression of B lymphocytes. Recently, we demonstrated that binding of CD20 Abs to B cells induces the rapid redistribution of up to 95% of CD20 molecules to low density, detergent-insoluble membrane microdomains and induces the appearance of an approximately 50-kDa tyrosine-phosphorylated protein in the same compartment. Active relocalization of CD20 may thus be critical to the initiation of signaling events by CD20. The CD20 cDNA sequence predicts a nonglycosylated protein with four transmembrane-spanning regions and intracellular amino and carboxyl termini. Here we provide verification of the location of both the intracellular and extracellular regions of the CD20 molecule and identify a membrane-proximal sequence in the cytoplasmic carboxyl tail that is required for CD20 to redistribute to detergent-insoluble membrane microdomains.
Collapse
Affiliation(s)
- Maria J. Polyak
- Immunology Research Group, Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada
| | - Sweta H. Tailor
- Immunology Research Group, Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada
| | - Julie P. Deans
- Immunology Research Group, Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada
| |
Collapse
|
18
|
Popoff IJ, Savage JA, Blake J, Johnson P, Deans JP. The association between CD20 and Src-family Tyrosine kinases requires an additional factor. Mol Immunol 1998; 35:207-14. [PMID: 9736336 DOI: 10.1016/s0161-5890(98)00042-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
CD20 is a B cell surface protein which can initiate intracellular signals involving tyrosine kinase activation, and modify B cell growth and differentiation. CD20 is tightly associated with the Src-family kinases Lyn, Fyn and Lck; however, the mechanism of interaction remains to be determined. Association between CD20 and Src-family kinases has been detected in peripheral blood B cells and in 5 out of 8 unrelated B cell lines. The lack of CD20-associated kinase activity in some cell lines offered an opportunity to investigate the mechanism of CD20 associations. All 8 B cell lines were found to express Lyn, and, with one exception, all cell lines also expressed Fyn. Lck, however, was not detected in any of the cell lines in which CD20 failed to coprecipitate kinase activity. To test the possibility that Lck was required for assembly of the CD20 complex, Lck was transfected into one of the 3 CD20/kinase association-deficient lines, namely T51. CD20 did not coprecipitate kinase activity from the transfected T51 cells, despite their expression of high levels of exogenous Lck, as well as endogenous Lyn and Fyn. CD20 cDNA from T51 was sequenced and found to be normal. These data establish that association between CD20 and Src-family kinases requires an additional factor.
Collapse
Affiliation(s)
- I J Popoff
- Department of Medical Biochemistry, The University of Calgary, Alberta, Canada
| | | | | | | | | |
Collapse
|
19
|
Murayama Y, Mukai R, Sata T, Matsunaga S, Noguchi A, Yoshikawa Y. Transient expression of CD20 antigen (pan B cell marker) in activated lymph node T cells. Microbiol Immunol 1996; 40:467-71. [PMID: 8839435 DOI: 10.1111/j.1348-0421.1996.tb01096.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In contrast to the case of peripheral T cells, the surface expression of CD20 antigen and the expression of CD20 mRNA in monkey lymph node (LN) T cells underwent a noticeable increase when they were cultured with mitogen and interleukin-2 (IL-2). To confirm in vivo regulation of CD20 expression during the activation of LN T cells, we examined LNs derived from monkeys experimentally inoculated with simian immunodeficiency virus (SIV). Significant expression of CD20 antigen was detected in the T cells of the LNs at the stage of lymphadenopathy. These findings suggest that lymphocyte activation in the LNs induced expression of the CD20 molecule in some T cells.
Collapse
MESH Headings
- Animals
- Antigens, CD/analysis
- Antigens, CD20/genetics
- Antigens, CD20/immunology
- Antigens, Differentiation, T-Lymphocyte/analysis
- Cells, Cultured
- Lectins, C-Type
- Leukocytes, Mononuclear/cytology
- Leukocytes, Mononuclear/immunology
- Lymph Nodes/cytology
- Lymph Nodes/immunology
- Lymphocyte Activation
- Macaca mulatta
- RNA, Messenger
- Simian Acquired Immunodeficiency Syndrome/blood
- Simian Acquired Immunodeficiency Syndrome/immunology
- Simian Immunodeficiency Virus/immunology
- T-Lymphocytes/cytology
- T-Lymphocytes/immunology
- T-Lymphocytes/virology
Collapse
Affiliation(s)
- Y Murayama
- Institute of Basic Medical Sciences, University of Tsukuba, Ibaraki, Japan
| | | | | | | | | | | |
Collapse
|
20
|
Deans JP, Kalt L, Ledbetter JA, Schieven GL, Bolen JB, Johnson P. Association of 75/80-kDa phosphoproteins and the tyrosine kinases Lyn, Fyn, and Lck with the B cell molecule CD20. Evidence against involvement of the cytoplasmic regions of CD20. J Biol Chem 1995; 270:22632-8. [PMID: 7545683 DOI: 10.1074/jbc.270.38.22632] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
CD20, a non-glycosylated cell-surface protein expressed exclusively on B lymphocytes, is one of a family of 4-pass transmembrane molecules that also includes the beta chain of the high affinity receptor for IgE. The precise function of CD20 is unknown, although in vitro effects of CD20-specific antibodies on resting B cells indicate that it is able to transduce an extracellular signal affecting the G0/G1 cell cycle transition. Previous studies have demonstrated that CD20-initiated intracellular signals involve tyrosine kinase activation and that CD20 is tightly associated with both serine and tyrosine kinases. Here, analysis of CD20-associated molecules has revealed that CD20 is associated with the Src family tyrosine kinases p56/53lyn, p56lck, and p59fyn and with 75/80-kDa proteins phosphorylated in vivo on tyrosine residues. Mutagenesis of CD20 was performed to define regions of CD20 involved in intermolecular interactions. Mutants were analyzed in the human T lymphoblastoid cell line Molt-4, in which ectopically expressed wild-type CD20 associated with p59fyn, p56lck, and 75/80-kDa phosphoproteins. Deletion of major portions of the cytoplasmic regions of CD20 did not abolish its association with either p75/80 or tyrosine kinases. The interaction between CD20 and the Src-related kinases is therefore likely to be independent of CD20 cytoplasmic domains and may occur indirectly. The interaction may be mediated by the p75/80 phosphoproteins, which were found to be tightly associated with the Src family kinases isolated from the CD20 complex.
Collapse
Affiliation(s)
- J P Deans
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada
| | | | | | | | | | | |
Collapse
|
21
|
Engel P, Wagner N, Miller AS, Tedder TF. Identification of the ligand-binding domains of CD22, a member of the immunoglobulin superfamily that uniquely binds a sialic acid-dependent ligand. J Exp Med 1995; 181:1581-6. [PMID: 7535343 PMCID: PMC2191955 DOI: 10.1084/jem.181.4.1581] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
CD22 is a B cell-restricted member of the immunoglobulin (Ig) superfamily that functions as an adhesion receptor for leukocytes and erythrocytes. CD22 is unique among members of the Ig superfamily in that it has been suggested to bind a series of sialic acid-dependent ligands, potentially through different functional domains expressed by different splice variants of CD22. In this study, the epitopes identified by a large panel of function-blocking and non-function-blocking CD22 monoclonal antibodies were localized to specific Ig-like domains, revealing that all function-blocking monoclonal antibodies bound to the first and/or second Ig-like domains. Consistent with a single ligand-binding region, the two amino-terminal domains were the functional unit that mediated CD22 adhesion with lymphocytes, neutrophils, monocytes, and erythrocytes. The predominant cell surface species of CD22 was a full length 140,000 relative molecular mass seven Ig-like domain glycoprotein and a minor 130,000 relative molecular mass form lacking the fourth domain. While the two amino-terminal Ig-like domains of CD22 are structurally similar to those found in other members of the Ig superfamily involved in cell adhesion and containing an amino acid sequence motif associated with integrin recognition, site-directed mutagenesis of critical residues surrounding this motif did not disrupt CD22-mediated adhesion. These results demonstrate that the unique ligand-binding properties of CD22 are distinct from those of other members of the Ig superfamily involved in integrin-mediated cell adhesion.
Collapse
MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Monoclonal/immunology
- Antigens, CD/chemistry
- Antigens, CD/immunology
- Antigens, CD/metabolism
- Antigens, Differentiation, B-Lymphocyte/chemistry
- Antigens, Differentiation, B-Lymphocyte/immunology
- Antigens, Differentiation, B-Lymphocyte/metabolism
- Binding Sites
- Cell Adhesion
- Cell Adhesion Molecules
- Cell Line, Transformed
- Chlorocebus aethiops
- DNA Mutational Analysis
- DNA, Complementary/genetics
- Epitopes/chemistry
- Epitopes/immunology
- Erythrocytes/metabolism
- Humans
- Immunoglobulins
- Integrins/chemistry
- Lectins
- Leukocytes, Mononuclear/metabolism
- Ligands
- Mice
- Molecular Sequence Data
- Molecular Weight
- Multigene Family
- N-Acetylneuraminic Acid
- Protein Folding
- Protein Structure, Tertiary
- Recombinant Fusion Proteins/metabolism
- Sequence Alignment
- Sequence Homology, Amino Acid
- Sialic Acid Binding Ig-like Lectin 2
- Sialic Acids/physiology
- Tumor Cells, Cultured
Collapse
Affiliation(s)
- P Engel
- Department of Immunology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | | | | | | |
Collapse
|
22
|
Takase K, Terada N, Lucas JJ, Gelfand EW. Control of cell cycle entry and progression in mitogen-stimulated human B lymphocytes. J Cell Physiol 1995; 162:246-55. [PMID: 7529768 DOI: 10.1002/jcp.1041620210] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Tonsillar B lymphocytes were stimulated to proliferate by the mitogenic combination of phorbol dibutyrate and ionomycin. Progression through the cell cycle was monitored by measurements of cellular DNA and RNA content using flow cytometry. Changes in surface expression of class II MHC antigens and CD20 antigen were also monitored as early parameters of B lymphocyte activation and cell cycle progression. The results showed that about 60% of the population synchronously entered and progressed through the cell cycle. The transition from the resting state, signaled by increased RNA content, occurred about 12 to 24 hr after stimulation; S phase entry occurred at about 36 hr. Small, variable populations of cells appeared to be unresponsive to the stimuli, either because they were "preactivated" before in vitro stimulation or were already dying. The kinetics of appearance and accumulation of several cell cycle regulated/regulatory proteins were followed by immunoblotting. The proliferating cell nuclear antigen (PCNA) cyclin A and p33cdk2 proteins were either absent or present in very low amounts in resting cells and first became detectable in increased amount beginning at about 24 hr after stimulation; increased p34cdc2 protein was not detected until about 36 hr. Increased cellular content and phosphorylation of the p110Rb protein was already obvious by 24 hr after stimulation. The effects of several immunosuppressive agents were examined using purified B cells. Both cyclosporin A and an FK506 analogue were shown to inhibit proliferation of B lymphocytes, at the low doses also inhibitory to T cells.
Collapse
Affiliation(s)
- K Takase
- Department of Pediatrics, National Jewish Center for Immunology and Respiratory Medicine, Denver, Colorado 80206
| | | | | | | |
Collapse
|
23
|
Abstract
CD20 is a B-cell-specific cell-surface molecule with four membrane-spanning domains, as well as cytoplasmic N- and C-terminal domains. Here, Thomas Tedder and Pablo Engel discuss the suggestion that CD20 is a regulator of transmembrane Ca2+ conductance and plays an important functional role in B-cell activation, proliferation and differentiation.
Collapse
Affiliation(s)
- T F Tedder
- Dept of Immunology, Duke University Medical Center, Durham, NC 27710
| | | |
Collapse
|
24
|
Daish A, Hock BD, Hart DN. Characterization of a novel leucocyte activation antigen recognized by the antibody CMRF-37. Immunol Cell Biol 1994; 72:13-21. [PMID: 8157283 DOI: 10.1038/icb.1994.3] [Citation(s) in RCA: 2] [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
We describe a novel activation antigen recognized by the monoclonal antibody CMRF-37, which is absent or only weakly expressed on resting cells but is rapidly induced on T cells, B cells and monocytes following stimulation. Its kinetics of expression (12-24 h after the addition of the inductive signal) indicate that it is an early activation antigen. The cellular distribution and expression kinetics of the CMRF-37 antigen differ from other known activation antigens and as such should be a useful marker of human leucocyte activation.
Collapse
Affiliation(s)
- A Daish
- Haematology/Immunology Research Group, Christchurch Hospital, New Zealand
| | | | | |
Collapse
|
25
|
Bubien JK, Zhou LJ, Bell PD, Frizzell RA, Tedder TF. Transfection of the CD20 cell surface molecule into ectopic cell types generates a Ca2+ conductance found constitutively in B lymphocytes. J Biophys Biochem Cytol 1993; 121:1121-32. [PMID: 7684739 PMCID: PMC2119683 DOI: 10.1083/jcb.121.5.1121] [Citation(s) in RCA: 258] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
CD20 is a plasma membrane phosphoprotein expressed exclusively by B lymphocytes. mAb binding to CD20 alters cell cycle progression and differentiation, indicating that CD20 plays an essential role in B lymphocyte function. Whole-cell patch clamp and fluorescence microscopy measurements of plasma membrane ionic conductance and cytosolic-free Ca2+ activity, respectively, were used to directly examine CD20 function. Transfection of human T and mouse pre-B lymphoblastoid cell lines with CD20 cDNA and subsequent stable expression of CD20 specifically increased transmembrane Ca2+ conductance. Transfection of CD20 cDNA and subsequent expression of CD20 in nonlymphoid cells (human K562 erythroleukemia cells and mouse NIH-3T3 fibroblasts) also induced the expression of an identical transmembrane Ca2+ conductance. The binding of a CD20-specific mAb to CD20+ lymphoblastoid cells also enhanced the transmembrane Ca2+ conductance. The mAb-enhanced Ca2+ currents had the same conductance characteristics as the CD20-associated Ca2+ currents in CD20 cDNA-transfected cells. C20 is structurally similar to several ion channels; each CD20 monomer possesses four membrane spanning domains, and both the amino and carboxy termini reside within the cytoplasm. Biochemical cross-linking of cell-surface molecules with subsequent immunoprecipitation analysis of CD20 suggests that CD20 may be present as a multimeric oligomer within the membrane, as occurs with several known membrane channels. Taken together, these findings indicate that CD20 directly regulates transmembrane Ca2+ conductance in B lymphocytes, and suggest that multimeric complexes of CD20 may form Ca2+ conductive ion channels in the plasma membrane of B lymphoid cells.
Collapse
Affiliation(s)
- J K Bubien
- Department of Medicine, University of Alabama, Birmingham 35294
| | | | | | | | | |
Collapse
|
26
|
Salvaris E, Novotny JR, Welch K, Campbell L, Boyd AW. Characterization of two novel pre-B-cell lines (LK63 and LiLa-1): potential models of pre-B-cell differentiation. Leuk Res 1992; 16:655-63. [PMID: 1378917 DOI: 10.1016/0145-2126(92)90016-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In this report we describe two newly isolated pre-B acute lymphoblastic leukaemia cell lines. Both cell lines lack EBV as detected by the EBNA-1 gene probed Southern-blots. Neither cell line expressed the B-cell-specific CD20 antigen on the cell membrane. However surface expression of CD20 was induced by phorbol ester (TPA) on both LiLa-1 and LK63 cell lines. Other pre-B and B-cell lines, such as Reh, Nalm-1, and BALL-1 did not exhibit these changes in phenotype. Previous immunoprecipitation studies have noted that a broad 50-55 kD band co-precipitates with the characteristic 33-37 kD CD20 protein. We demonstrate that, while the 33-37 kD CD20 species was undetectable on resting LiLa-1 and LK63 cells, in each case a 50-55 kD protein was immunoprecipitated by the CD20 antibody. However, the failure to detect any cell surface CD20-associated antigen on the control cells by immunophenotyping indicated that the CD20 epitope of the 50-55 kD molecule was not expressed on the cell surface. Following exposure to TPA the 50-55 kD species was reduced over 48-72 h while the level of the p33-37 CD20 protein was increased. Northern-blot analysis showed that the 50-55 kD protein was not a cryptic form of CD20 as the uninduced cells contained no detectable CD20 mRNA. The decrease of the 50-55 kD protein and the acquisition of the mature CD20 molecule were paralleled by a decline in proliferative activity in both cell lines. As expression of CD20 by normal pre-B cells also coincides with the cessation of cell division and maturation towards a mature B-cell phenotype, these cell lines appear to represent models for a discrete stage of B-cell differentiation which may be valuable in defining the signals regulating pre-B-cell proliferation.
Collapse
Affiliation(s)
- E Salvaris
- Lions Clinical Cancer Research Laboratory, Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | | | | | | | | |
Collapse
|