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Babushku T, Lechner M, Ehrenberg S, Rambold U, Schmidt-Supprian M, Yates AJ, Rane S, Zimber-Strobl U, Strobl LJ. Notch2 controls developmental fate choices between germinal center and marginal zone B cells upon immunization. Nat Commun 2024; 15:1960. [PMID: 38438375 PMCID: PMC10912316 DOI: 10.1038/s41467-024-46024-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 02/12/2024] [Indexed: 03/06/2024] Open
Abstract
Sustained Notch2 signals induce trans-differentiation of Follicular B (FoB) cells into Marginal Zone B (MZB) cells in mice, but the physiology underlying this differentiation pathway is still elusive. Here, we demonstrate that most B cells receive a basal Notch signal, which is intensified in pre-MZB and MZB cells. Ablation or constitutive activation of Notch2 upon T-cell-dependent immunization reveals an interplay between antigen-induced activation and Notch2 signaling, in which FoB cells that turn off Notch2 signaling enter germinal centers (GC), while high Notch2 signaling leads to generation of MZB cells or to initiation of plasmablast differentiation. Notch2 signaling is dispensable for GC dynamics but appears to be re-induced in some centrocytes to govern expansion of IgG1+ GCB cells. Mathematical modelling suggests that antigen-activated FoB cells make a Notch2 dependent binary fate-decision to differentiate into either GCB or MZB cells. This bifurcation might serve as a mechanism to archive antigen-specific clones into functionally and spatially diverse B cell states to generate robust antibody and memory responses.
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Affiliation(s)
- Tea Babushku
- Research Unit Gene Vectors, Research Group B Cell Development and Activation, Helmholtz Zentrum München, German Research Center for Environmental Health, Feodor-Lynen-Str. 21, D-81377, Munich, Germany
- TranslaTUM, Center for Translational Cancer Research, Technical University of Munich, Einsteinstraße 25, D-81675, Munich, Germany
| | - Markus Lechner
- Research Unit Gene Vectors, Research Group B Cell Development and Activation, Helmholtz Zentrum München, German Research Center for Environmental Health, Feodor-Lynen-Str. 21, D-81377, Munich, Germany
| | - Stefanie Ehrenberg
- Research Unit Gene Vectors, Research Group B Cell Development and Activation, Helmholtz Zentrum München, German Research Center for Environmental Health, Feodor-Lynen-Str. 21, D-81377, Munich, Germany
| | - Ursula Rambold
- Institute of Asthma and Allergy Prevention, Helmholtz Zentrum München, German Research Center for Environmental Health, Feodor-Lynen-Str. 21, D-81377, Munich, Germany
| | - Marc Schmidt-Supprian
- TranslaTUM, Center for Translational Cancer Research, Technical University of Munich, Einsteinstraße 25, D-81675, Munich, Germany
| | - Andrew J Yates
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, 630 West 168th Street, New York, NY, 10032, USA
| | - Sanket Rane
- Irving Institute for Cancer Dynamics, Columbia University, 1190 Amsterdam Ave, New York, 10027, USA
| | - Ursula Zimber-Strobl
- Research Unit Gene Vectors, Research Group B Cell Development and Activation, Helmholtz Zentrum München, German Research Center for Environmental Health, Feodor-Lynen-Str. 21, D-81377, Munich, Germany.
- Institute of Lung Health and Immunity (LHI), Helmholtz Munich, Comprehensive Pneumology Center (CPC-M), Member of the German Center for Lung Research (DZL), Ingolstädter Landstraße 1, 85764, Neuherberg, Germany.
| | - Lothar J Strobl
- Research Unit Gene Vectors, Research Group B Cell Development and Activation, Helmholtz Zentrum München, German Research Center for Environmental Health, Feodor-Lynen-Str. 21, D-81377, Munich, Germany
- Institute of Lung Health and Immunity (LHI), Helmholtz Munich, Comprehensive Pneumology Center (CPC-M), Member of the German Center for Lung Research (DZL), Ingolstädter Landstraße 1, 85764, Neuherberg, Germany
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Liu D, Winer BY, Chou MY, Tam H, Xu Y, An J, Gardner JM, Cyster JG. Dynamic encounters with red blood cells trigger splenic marginal zone B cell retention and function. Nat Immunol 2024; 25:142-154. [PMID: 38049580 PMCID: PMC10761324 DOI: 10.1038/s41590-023-01690-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Accepted: 10/24/2023] [Indexed: 12/06/2023]
Abstract
Spleen marginal zone (MZ) B cells are important for antibody responses against blood-borne antigens. The signals they use to detect exposure to blood are not well defined. Here, using intravital two-photon microscopy in mice, we observe transient contacts between MZ B cells and red blood cells that are in flow. We show that MZ B cells use adhesion G-protein-coupled receptor ADGRE5 (CD97) for retention in the spleen. CD97 function in MZ B cells depends on its ability to undergo autoproteolytic cleavage and signaling via Gα13 and ARHGEF1. Red blood cell expression of the CD97 ligand CD55 is required for MZ B cell homeostasis. Applying a pulling force on CD97-transfected cells using an optical C-trap and CD55+ beads leads to accumulation of active RhoA and membrane retraction. Finally, we show that CD97 deficiency leads to a reduced T cell-independent IgM response. Thus, our studies provide evidence that MZ B cells use mechanosensing to position in a manner that enhances antibody responses against blood-borne antigens.
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Affiliation(s)
- Dan Liu
- Howard Hughes Medical Institute and Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA.
- Westlake Laboratory of Life Sciences and Biomedicine, Westlake University School of Life Sciences, Institute of Basic Medical Sciences and Westlake Institute for Advanced Study, Hangzhou, China.
| | - Benjamin Y Winer
- Howard Hughes Medical Institute and Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Marissa Y Chou
- Howard Hughes Medical Institute and Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA
| | - Hanson Tam
- Howard Hughes Medical Institute and Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA
| | - Ying Xu
- Howard Hughes Medical Institute and Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA
| | - Jinping An
- Howard Hughes Medical Institute and Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA
| | - James M Gardner
- Diabetes Center and Department of Surgery, University of California, San Francisco, San Francisco, CA, USA
| | - Jason G Cyster
- Howard Hughes Medical Institute and Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA.
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3
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Markocsy A, Bobcakova A, Petrovicova O, Kapustova L, Malicherova Jurkova E, Schniederova M, Petriskova J, Cibulka M, Hyblova M, Jesenak M. Association Between Cytometric Biomarkers, Clinical Phenotype, and Complications of Common Variable Immunodeficiency. Cureus 2024; 16:e52941. [PMID: 38406025 PMCID: PMC10894026 DOI: 10.7759/cureus.52941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/20/2024] [Indexed: 02/27/2024] Open
Abstract
BACKGROUND Common variable immunodeficiency (CVID) is a heterogeneous group of immune disorders. The patients are classified according to the clinical manifestation with the infection-only phenotype (CVIDinf) and CVID with immune dysregulation (CVIDid). METHODS We performed a retrospective clinical analysis of 64 CVID patients (34 males, 53.13%; mean age: 41.4 years; SD: ±21.4 years). We divided the patients into subgroups according to the clinical manifestation (CVIDinf and CVIDid) and according to B cell phenotypic profiling after performing flow cytometry with the use of the EUROclass classification. We compared clinical manifestations, selected laboratory parameters, and therapy in these groups. All CVIDid patients were tested after the manifestation of complications associated with immune dysregulation and in eight patients during the immunosuppressive treatment (systemic corticosteroids and hydroxychloroquine). RESULTS Two-thirds of patients in our cohort had symptoms resulting from immune dysregulation. Almost half of the patients had autoimmune complications. A higher proportion of marginal zone B cells was associated with autoimmune complications. A lower percentage of naïve B cells was connected to autoimmunity, whereas a lower proportion of transitional B cells was associated with rheumatic diseases and splenomegaly. Patients with lymphadenopathy had a higher percentage of double-negative T cells and a lower percentage of switched memory B cells. We performed molecular-genetic testing in 28% (n = 17) of patients and found a causal pathogenic variant in 23.5% (n = 4) of this group. CONCLUSION Based on our results, there is an association between specific cytometric parameters, clinical phenotype, and complications of CVID. The use of the subpopulations of B cells can be helpful in the diagnosis of these specific clinical complications in CVID patients and could help to personalise the therapeutic approach.
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Affiliation(s)
- Adam Markocsy
- Department of Paediatrics, Martin University Hospital, Martin, SVK
| | - Anna Bobcakova
- Department of Pulmonology and Phthisiology, Jessenius Faculty of Medicine, Comenius University in Bratislava, Martin, SVK
| | - Otilia Petrovicova
- Department of Paediatrics, Jessenius Faculty of Medicine, Comenius University in Bratislava, Martin, SVK
| | - Lenka Kapustova
- Department of Paediatrics, Martin University Hospital, Martin, SVK
| | | | - Martina Schniederova
- Department of Clinical Immunology and Allergology, Martin University Hospital, Martin, SVK
| | - Jela Petriskova
- Department of Clinical Immunology and Allergology, Martin University Hospital, Martin, SVK
| | - Michal Cibulka
- Department of Clinical Immunology and Allergology, Martin University Hospital, Martin, SVK
| | | | - Milos Jesenak
- Department of Clinical Immunology and Allergology, Jessenius Faculty of Medicine, Comenius University in Bratislava, Martin, SVK
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Salerno F, Howden AJM, Matheson LS, Gizlenci Ö, Screen M, Lingel H, Brunner-Weinzierl MC, Turner M. An integrated proteome and transcriptome of B cell maturation defines poised activation states of transitional and mature B cells. Nat Commun 2023; 14:5116. [PMID: 37612319 PMCID: PMC10447577 DOI: 10.1038/s41467-023-40621-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 08/03/2023] [Indexed: 08/25/2023] Open
Abstract
During B cell maturation, transitional and mature B cells acquire cell-intrinsic features that determine their ability to exit quiescence and mount effective immune responses. Here we use label-free proteomics to quantify the proteome of B cell subsets from the mouse spleen and map the differential expression of environmental sensing, transcription, and translation initiation factors that define cellular identity and function. Cross-examination of the full-length transcriptome and proteome identifies mRNAs related to B cell activation and antibody secretion that are not accompanied by detection of the encoded proteins. In addition, proteomic data further suggests that the translational repressor PDCD4 restrains B cell responses, in particular those from marginal zone B cells, to a T-cell independent antigen. In summary, our molecular characterization of B cell maturation presents a valuable resource to further explore the mechanisms underpinning the specialized functions of B cell subsets, and suggest the presence of 'poised' mRNAs that enable expedited B cell responses.
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Affiliation(s)
- Fiamma Salerno
- Immunology programme, The Babraham Institute, Cambridge, UK.
| | | | | | - Özge Gizlenci
- Immunology programme, The Babraham Institute, Cambridge, UK
| | - Michael Screen
- Immunology programme, The Babraham Institute, Cambridge, UK
| | - Holger Lingel
- Department of Experimental Pediatrics, Otto-von-Guericke-University, Magdeburg, Germany
| | | | - Martin Turner
- Immunology programme, The Babraham Institute, Cambridge, UK.
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5
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Muacevic A, Adler JR, Lamture Y, Singh S, Shukla R. A Rare Case of Mucosa-Associated Lymphoid Tissue Lymphoma in the Ileum. Cureus 2022; 14:e32851. [PMID: 36712712 PMCID: PMC9875551 DOI: 10.7759/cureus.32851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 12/22/2022] [Indexed: 12/24/2022] Open
Abstract
The body contains mucosa-associated lymphoid tissue (MALT), with the greatest amount located in the gastrointestinal (Gl) tract. Lymphoma may form when the cell growth in this tissue is aberrant. The small intestine is a common extranodular site of lymphoma, a systemic illness. Additionally, it has been proposed that MALT lymphomas (MALTomas) arise as a result of chronic and persistent immunological activation, either of an autoimmune or infectious type. The MALToma that develops in the duodenum is typically thought to be unrelated to Helicobacter pylori infection. However, some examples show that lymphoma regressed when H. pylori were removed.
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Lechner M, Engleitner T, Babushku T, Schmidt-Supprian M, Rad R, Strobl LJ, Zimber-Strobl U. Notch2-mediated plasticity between marginal zone and follicular B cells. Nat Commun 2021; 12:1111. [PMID: 33597542 PMCID: PMC7889629 DOI: 10.1038/s41467-021-21359-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 01/22/2021] [Indexed: 02/07/2023] Open
Abstract
Follicular B (FoB) and marginal zone B (MZB) cells are functionally and spatially distinct mature B cell populations in the spleen, originating from a Notch2-dependent fate decision after splenic influx of immature transitional B cells. In the B cell follicle, a Notch2-signal is provided by DLL-1-expressing fibroblasts. However, it is unclear whether FoB cells, which are in close contact with these DLL-1 expressing fibroblasts, can also differentiate to MZB cells if they receive a Notch2-signal. Here, we show induced Notch2IC-expression in FoB cells re-programs mature FoB cells into bona fide MZB cells as is evident from the surface phenotype, localization, immunological function and transcriptome of these cells. Furthermore, the lineage conversion from FoB to MZB cells occurs in immunocompetent wildtype mice. These findings demonstrate plasticity between mature FoB and MZB cells that can be driven by a singular signaling event, the activation of Notch2.
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Affiliation(s)
- Markus Lechner
- Research Unit Gene Vectors, Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, München, Germany
| | - Thomas Engleitner
- TranslaTUM, Center for Translational Cancer Research, Technical University of Munich, München, Germany
- Institute of Molecular Oncology and Functional Genomics, TUM School of Medicine, Technical University of Munich, Munich, Germany
- German Cancer Consortium (DKTK), Heidelberg, Germany
| | - Tea Babushku
- Research Unit Gene Vectors, Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, München, Germany
| | - Marc Schmidt-Supprian
- TranslaTUM, Center for Translational Cancer Research, Technical University of Munich, München, Germany
- German Cancer Consortium (DKTK), Heidelberg, Germany
- Institute of Experimental Hematology, TUM School of Medicine, Technical University of Munich, Munich, Germany
| | - Roland Rad
- TranslaTUM, Center for Translational Cancer Research, Technical University of Munich, München, Germany
- Institute of Molecular Oncology and Functional Genomics, TUM School of Medicine, Technical University of Munich, Munich, Germany
- German Cancer Consortium (DKTK), Heidelberg, Germany
| | - Lothar J Strobl
- Research Unit Gene Vectors, Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, München, Germany
| | - Ursula Zimber-Strobl
- Research Unit Gene Vectors, Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, München, Germany.
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Reynaud CA, Descatoire M, Dogan I, Huetz F, Weller S, Weill JC. IgM memory B cells: a mouse/human paradox. Cell Mol Life Sci 2012; 69:1625-34. [PMID: 22481437 PMCID: PMC3337997 DOI: 10.1007/s00018-012-0971-z] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2012] [Revised: 03/13/2012] [Accepted: 03/13/2012] [Indexed: 11/14/2022]
Abstract
Humoral memory is maintained by two types of persistent cells, memory B cells and plasma cells, which have different phenotypes and functions. Long-lived plasma cells can survive for a lifespan within a complex niche in the bone marrow and provide continuous protective serum antibody levels. Memory B cells reside in secondary lymphoid organs, where they can be rapidly mobilized upon a new antigenic encounter. Surface IgG has long been taken as a surrogate marker for memory in the mouse. Recently, however, we have brought evidence for a long-lived IgM memory B cell population in the mouse, while we have also argued that, in humans, these same cells are not classical memory B cells but marginal zone (MZ) B cells which, as opposed to their mouse MZ counterpart, recirculate and carry a mutated B cell receptor. In this review, we will discuss these apparently paradoxical results.
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Affiliation(s)
- Claude-Agnès Reynaud
- Faculté de Médecine, Site Necker-Enfants Malades, INSERM U783 “Développement du système immunitaire”, Université Paris Descartes, 156 rue de Vaugirard, 75730 Paris Cedex 15, France
| | - Marc Descatoire
- Faculté de Médecine, Site Necker-Enfants Malades, INSERM U783 “Développement du système immunitaire”, Université Paris Descartes, 156 rue de Vaugirard, 75730 Paris Cedex 15, France
| | - Ismail Dogan
- Faculté de Médecine, Site Necker-Enfants Malades, INSERM U783 “Développement du système immunitaire”, Université Paris Descartes, 156 rue de Vaugirard, 75730 Paris Cedex 15, France
| | - François Huetz
- Faculté de Médecine, Site Necker-Enfants Malades, INSERM U783 “Développement du système immunitaire”, Université Paris Descartes, 156 rue de Vaugirard, 75730 Paris Cedex 15, France
- Unité de Biologie des Populations Lymphocytaires, CNRS URA 1961, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Sandra Weller
- Faculté de Médecine, Site Necker-Enfants Malades, INSERM U783 “Développement du système immunitaire”, Université Paris Descartes, 156 rue de Vaugirard, 75730 Paris Cedex 15, France
| | - Jean-Claude Weill
- Faculté de Médecine, Site Necker-Enfants Malades, INSERM U783 “Développement du système immunitaire”, Université Paris Descartes, 156 rue de Vaugirard, 75730 Paris Cedex 15, France
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Suzuki A, Kaisho T, Ohishi M, Tsukio-Yamaguchi M, Tsubata T, Koni PA, Sasaki T, Mak TW, Nakano T. Critical roles of Pten in B cell homeostasis and immunoglobulin class switch recombination. J Exp Med 2003; 197:657-67. [PMID: 12615906 PMCID: PMC2193827 DOI: 10.1084/jem.20021101] [Citation(s) in RCA: 185] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Pten is a tumor suppressor gene mutated in human cancers. We used the Cre-loxP system to generate a B cell-specific mutation of Pten in mice (bPten(flox/flox)mice). bPten(flox/flox) mice showed elevated numbers of B1a cells and increased serum autoantibodies. Among B2 cells in bPten(flox/flox) spleens, numbers of marginal zone B (MZB) cells were significantly increased while those of follicular B (FOB) cells were correspondingly decreased. Pten-deficient B cells hyperproliferated, were resistant to apoptotic stimuli, and showed enhanced migration. The survival kinase PKB/Akt was highly activated in Pten-deficient splenic B cells. In addition, immunoglobulin class switch recombination was defective and induction of activation-induced cytidine deaminase (AID) was impaired. Thus, Pten plays a role in developmental fate determination of B cells and is an indispensable regulator of B cell homeostasis.
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Affiliation(s)
- Akira Suzuki
- Department of Molecular Cell Biology, Research Institute for Microbial Disease, Osaka University, Osaka 565-0871, Japan
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Abstract
To study homeostasis of peripheral B lymphocytes in the absence of B cell influx from the bone marrow, we generated a mouse mutant in which the recombination-activating gene (RAG)-2 can be inducibly deleted. When RAG-2 was deleted at the age of 8-10 wk, splenic naive follicular B cells were gradually lost over a year of observation, with a half-life of approximately 4.5 mo. By contrast, the pool of marginal zone B cells in the spleen and of B-1 cells in the peritoneal cavity were kept at normal level. In lymph nodes, approximately 90% of the B cells were lost within 4 mo, and B cell numbers remained constant thereafter. Mice in which RAG-2 was deleted at birth maintained a small population of activated B cells with an increased proportion of marginal zone B cells. Additionally, an increase of the pool of IgM secreting cells and B-1a cells was observed.
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Affiliation(s)
- Zhenyue Hao
- Department of Immunology, Institute for Genetics, University of Cologne, D-50931 Cologne, Germany
| | - Klaus Rajewsky
- Department of Immunology, Institute for Genetics, University of Cologne, D-50931 Cologne, Germany
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10
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Abstract
Interleukin 7 is a crucial factor for the development of murine T and B lymphocytes. We now report that, in the absence of interleukin 7, B lymphocyte production takes place exclusively during fetal and perinatal life, ceasing after 7 wk of age. In peripheral organs, however, the pool of B lymphocytes is stable throughout adult life and consists only of cells that belong to the B1 and marginal zone (MZ) compartments. This is accompanied by a 50-fold increase in the frequency of immunoglobulin (Ig)M- and IgG-secreting cells, and the concentration of serum immunoglobulins is increased three- to fivefold. Both the MZ phenotype and the increase in serum IgM are T cell independent. These findings reveal a previously undescribed pathway of B lymphopoiesis that is active in early life and is interleukin 7 independent. This pathway generates B1 cells and a normal sized MZ B lymphocyte compartment.
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Affiliation(s)
| | | | - Ana Cumano
- Unité du Developpement des Lymphocytes (Centre National de la Recherche Scientific, Unité de Recherche Associée 1961), Institut Pasteur, 75724 Paris Cedex 15, France
| | | | - Paulo Vieira
- Instituto Gulbenkian de Ciência, 2781 Oeiras, Portugal
- Unité du Developpement des Lymphocytes (Centre National de la Recherche Scientific, Unité de Recherche Associée 1961), Institut Pasteur, 75724 Paris Cedex 15, France
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Abstract
Memory B cells isolated from human tonsils are characterized by an activated cell surface phenotype, localization to mucosal epithelium, expression of somatically mutated immunoglobulin (Ig) variable (V) region genes, and a preferential differentiation into plasma cells in vitro. In spleens of both humans and rodents, a subset of memory B cells is believed to reside in the marginal zone of the white pulp. Similar to tonsil-derived memory B cells, splenic marginal zone B cells can be distinguished from naive follicular B cells by a distinct cell surface phenotype and by the presence of somatic mutations in their Ig V region genes. Although differences exist between human naive and memory B cells, no cell surface molecules have been identified that positively identify all memory B cells. In this study, we have examined the expression of the receptor-type protein tyrosine phosphatase CD148 on human B cells. CD148(+) B cells present in human spleen exhibited characteristics typical of memory B cells. These included an activated phenotype, localization to the marginal zone, the expression of somatically mutated Ig V region genes, and the preferential differentiation into plasma cells. In contrast, CD148(-) B cells appeared to be naive B cells due to localization to the mantle zone, the expression of surface antigens typical of unstimulated B cells, and the expression of unmutated Ig V region genes. Interestingly, CD148(+) B cells also coexpressed CD27, whereas CD148(-) B cells were CD27(-). These results identify CD148 and CD27 as markers which positively identify memory B cells present in human spleen. Thus, assessing expression of these molecules may be a convenient way to monitor the development of memory B cell responses in immunocompromised individuals or in vaccine trials.
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Affiliation(s)
- S G Tangye
- Department of Immunobiology, DNAX Research Institute of Molecular and Cellular Biology, Palo Alto, California 94304, USA.
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