In Vitro Study Of The Mechanisms Involved In The Bone Marrow Mesenchymal Stromal Cell Modulatory Effect On B Cell Function

Abstract Human bone marrow Mesenchymal Stromal Cells (MSC) are potent modulators of T cell activation and proliferation, mainly through the production of partially defined soluble factors, including the IFN-g-induced tryptophan-degrading enzyme IDO, a key immunosuppressive effector pathway. Actually, MSC may affect the functions of virtually all immune effector cells, including B cells. However, current literature concerning MSC immunomodulatory activity on B cells is still controversial, due to both biological peculiarities of B cells, which do not produce IFN-γ, a key MSC-triggering cytokine, and to different and poorly comparable experimental approaches. Human purified B cells, either resting or activated for 4 days with a stimulation cocktail (CD40 ligand + enhancer polyhistidine mAb MAB050 + rhIL-2 + mouse F(ab’)2 anti-human IgM/IgA/IgG + CpG oligodeoxynucleotide 2006) were co-cultured with MSC, either at resting conditions or following inflammatory priming (MSC pre-incubation with IFN-γ + TNF-α for 48 hours), or with MSC supernatants. CD27-positive (memory) and CD27-negative (naïve) B cell survival, proliferation, and intracellular activation status (through signaling network analysis by Phosphoflow) were assessed. Our results showed that MSC are normally supportive cells, not intrinsically capable of suppressing B cell proliferation, and require inflammatory priming to acquire B cell inhibitory potential. Inflammatory-primed MSC impair significantly activated B cell growth in a cell contact-independent manner, as supernatant is sufficient to provide maximal inhibition of B cell proliferation. B cell inhibition by MSC is not related to either induction of B cell apoptosis or early signaling events necessary for B cell activation. In addition, IDO pathway triggered in IFN-γ-primed MSC seems to have a role also in B cell inhibition by interfering with the tryptophan metabolism. Overall, B cell behavior following the interaction with MSC depends on the functional state of both B cells and MSC. The role of IDO in B cell regulation needs further investigation, as it may be relevant to develop new therapeutic approaches in pathological conditions related to B cell hyper-activation. Disclosures: No relevant conflicts of interest to declare.

Download Full-text

P0404B CELLS FROM PATIENTS WITH GRANULOMATOSIS WITH POLYANGIITIS FAIL TO REGULATE T CELL INTERFERON GAMMA RELEASE BUT DO REGULATE OTHER ASPECTS OF T CELL ACTIVATION

Nephrology Dialysis Transplantation ◽

10.1093/ndt/gfaa142.p0404 ◽

2020 ◽

Vol 35 (Supplement_3) ◽

Author(s):

Srinivas Puli ◽

Daniel Appelgren ◽

Thomas Hellmark ◽

Mårten Segelmark

Keyword(s):

Cell Proliferation ◽

T Cell ◽

B Cells ◽

T Cell Activation ◽

Cell Activation ◽

Granulomatosis With Polyangiitis ◽

Systemic Vasculitis ◽

T Cell Proliferation ◽

Ifn Γ ◽

Active Disease

Abstract Background and Aims Regulatory features of B-cells have gained increased attention in patients with systemic vasculitis, including granulomatosis with polyangiitis (GPA). The aim with this study was to investigate the frequencies and phenotypes of two putative regulatory B (Breg) cell populations and assess the capacity of B-cells from GPA patients to regulate T-cell activation. Method 37 GPA patients (22 remission and 15 active) and 31 healthy controls (HC) were included for measurement of CD19+CD24highCD27+ (memory) and CD19+CD24highCD38high (transitional) Breg cells, and 11 GPA patients in remission and 12 HC for the functional studies of B-cells. HC were matched for age and gender. Results Memory Breg cells were reduced in GPA both during active disease and remission compared with HC, whereas transitional Breg cells did not differ between the groups. Memory Breg cells consisted of less CD25+ cells during both active disease and remission but expressed more PD-L1 and CD86 during remission compared with active disease and HC. B-cells from GPA patients regulated T-cell proliferation and IL-17a production but failed to regulate IFN-γ production (Fig 1). The levels of IFN-γ and the IFN-γ regulated cytokine CXCL10 were elevated in patient plasma. Conclusion Despite reduced levels and altered phenotypes of memory Breg cells, the capacity of GPA patient B-cells to regulate T-cell proliferation and IL-17a production was unaffected. However, we found a profound inability of patient B-cells to regulate T-cell IFN-γ production. This alteration could be important for the persistent inflammation that continues during remission and results in the chronic relapsing nature of the disease

Download Full-text

B cell IFN-γ receptor signaling promotes autoimmune germinal centers via cell-intrinsic induction of BCL-6

Journal of Experimental Medicine ◽

10.1084/jem.20151724 ◽

2016 ◽

Vol 213 (5) ◽

pp. 733-750 ◽

Cited By ~ 91

Author(s):

Shaun W. Jackson ◽

Holly M. Jacobs ◽

Tanvi Arkatkar ◽

Elizabeth M. Dam ◽

Nicole E. Scharping ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

T Cell Activation ◽

Lupus Erythematosus ◽

Cell Activation ◽

B Cell Lymphoma ◽

Cell Receptor ◽

Lupus Pathogenesis ◽

Ifn Γ

Dysregulated germinal center (GC) responses are implicated in the pathogenesis of human autoimmune diseases, including systemic lupus erythematosus (SLE). Although both type 1 and type 2 interferons (IFNs) are involved in lupus pathogenesis, their respective impacts on the establishment of autoimmune GCs has not been addressed. In this study, using a chimeric model of B cell-driven autoimmunity, we demonstrate that B cell type 1 IFN receptor signals accelerate, but are not required for, lupus development. In contrast, B cells functioning as antigen-presenting cells initiate CD4+ T cell activation and IFN-γ production, and strikingly, B cell–intrinsic deletion of the IFN-γ receptor (IFN-γR) abrogates autoimmune GCs, class-switched autoantibodies (auto-Abs), and systemic autoimmunity. Mechanistically, although IFN-γR signals increase B cell T-bet expression, B cell–intrinsic deletion of T-bet exerts an isolated impact on class-switch recombination to pathogenic auto-Ab subclasses without impacting GC development. Rather, in both mouse and human B cells, IFN-γ synergized with B cell receptor, toll-like receptor, and/or CD40 activation signals to promote cell-intrinsic expression of the GC master transcription factor, B cell lymphoma 6 protein. Our combined findings identify a novel B cell–intrinsic mechanism whereby IFN signals promote lupus pathogenesis, implicating this pathway as a potential therapeutic target in SLE.

Download Full-text

702 Dual blockade of the PD-1 checkpoint pathway and the adenosinergic negative feedback signaling pathway with a PD-1/CD73 bispecific antibody for cancer immune therapy

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2020-sitc2020.0702 ◽

2020 ◽

Vol 8 (Suppl 3) ◽

pp. A744-A744

Author(s):

Tingting Zhong ◽

Zhaoliang Huang ◽

Xinghua Pang ◽

Na Chen ◽

Xiaoping Jin ◽

...

Keyword(s):

T Cell ◽

B Cells ◽

B Cell ◽

T Cell Activation ◽

Negative Feedback ◽

Immune Suppression ◽

Specific Antibody ◽

Cell Activation ◽

Immune Therapy ◽

B Cell Activation

BackgroundCD73 (ecto-5’-nucleotidase) is an ecto-nucleotidase that dephosphorylate AMP to form adenosine. Activation of adenosine signaling pathway in immune cells leads to the suppression of effector functions, down-regulate macrophage phagocytosis, inhibit pro-inflammatory cytokine release, as well as yield aberrantly differentiated dendritic cells producing pro-tumorigenic molecules.1 In the tumor microenvironment, adenosinergic negative feedback signaling facilitated immune suppression is considered an important mechanism for immune evasion of cancer cells.2 3 Combination of CD73 and anti-PD-1 antibody has shown promising activity in suppressing tumor growth. Hence, we developed AK119, an anti- human CD73 monoclonal antibody, and AK123,a bi-specific antibody targeting both PD-1 and CD73 for immune therapy of cancer.MethodsAK119 is a humanized antibody against CD73 and AK123 is a tetrameric bi-specific antibody targeting PD-1 and CD73. Binding assays of AK119 and AK123 to antigens, and antigen expressing cells were performed by using ELISA, Fortebio, and FACS assays. In-vitro assays to investigate the activity of AK119 and AK123 to inhibit CD73 enzymatic activity in modified CellTiter-Glo assay, to induce endocytosis of CD73, and to activate B cells were performed. Assay to evaluate AK123 activity on T cell activation were additionally performed. Moreover, the activities of AK119 and AK123 to mediate ADCC, CDC in CD73 expressing cells were also evaluated.ResultsAK119 and AK123 could bind to its respective soluble or membrane antigens expressing on PBMCs, MDA-MB-231, and U87-MG cells with high affinity. Results from cell-based assays indicated that AK119 and AK123 effectively inhibited nucleotidase enzyme activity of CD73, mediated endocytosis of CD73, and induced B cell activation by upregulating CD69 and CD83 expression on B cells, and showed more robust CD73 blocking and B cell activation activities compared to leading clinical candidate targeting CD73. AK123 could also block PD-1/PD-L1 interaction and enhance T cell activation.ConclusionsIn summary, AK119 and AK123 represent good preclinical biological properties, which support its further development as an anti-cancer immunotherapy or treating other diseases.ReferencesDeaglio S, Dwyer KM, Gao W, Friedman D, Usheva A, Erat A, Chen JF, Enjyoji K, Linden J, Oukka M, et al. Adenosine generation catalyzed by CD39 and CD73 expressed on regulatory T cells mediates immune suppression. J Exp Med 2007; 204:1257–65.Huang S, Apasov S, Koshiba M, Sitkovsky M. Role of A2a extracellular adenosine receptor-mediated signaling in adenosine-mediated inhibition of T-cell activation and expansion. Blood. 1997; 90:1600–10.Novitskiy SV, Ryzhov S, Zaynagetdinov R, Goldstein AE, Huang Y, Tikhomirov OY, Blackburn MR, Biaggioni I,Carbone DP, Feoktistov I, et al. Adenosine receptors in regulation of dendritic cell differentiation and function. Blood 2008; 112:1822–31.

Download Full-text

The Role of B Cells in Adult and Paediatric Liver Injury

Frontiers in Immunology ◽

10.3389/fimmu.2021.729143 ◽

2021 ◽

Vol 12 ◽

Author(s):

Arzoo M. Patel ◽

Yuxin S. Liu ◽

Scott P. Davies ◽

Rachel M. Brown ◽

Deirdre A. Kelly ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

T Cell Activation ◽

Cell Biology ◽

Liver Diseases ◽

Cell Activation ◽

Persistent Inflammation ◽

Stage Disease ◽

End Stage ◽

The Impact

B lymphocytes are multitasking cells that direct the immune response by producing pro- or anti-inflammatory cytokines, by presenting processed antigen for T cell activation and co-stimulation, and by turning into antibody-secreting cells. These functions are important to control infection in the liver but can also exacerbate tissue damage and fibrosis as part of persistent inflammation that can lead to end stage disease requiring a transplant. In transplantation, immunosuppression increases the incidence of lymphoma and often this is of B cell origin. In this review we bring together information on liver B cell biology from different liver diseases, including alcohol-related and metabolic fatty liver disease, autoimmune hepatitis, primary biliary and primary sclerosing cholangitis, viral hepatitis and, in infants, biliary atresia. We also discuss the impact of B cell depletion therapy in the liver setting. Taken together, our analysis shows that B cells are important in the pathogenesis of liver diseases and that further research is necessary to fully characterise the human liver B cell compartment.

Download Full-text

Cellular side of acquired immunity (B cells)

Oxford Textbook of Rheumatology ◽

10.1093/med/9780199642489.003.0050_update_001 ◽

2013 ◽

pp. 371-378

Author(s):

Thomas Dörner ◽

Peter E. Lipsky

Keyword(s):

B Cells ◽

B Cell ◽

T Cell Activation ◽

Cell Activation ◽

Plasma Cells ◽

Adaptive Immune System ◽

Adaptive Immune ◽

B Cell Homeostasis ◽

Anti Cd20 ◽

Antigen Presenting

B cells have gained interest in rheumatoid arthritis (RA) beyond being the precursors of antibody-producing plasma cells since they are also a broader component of the adaptive immune system. They are capable of functioning as antigen-presenting cells for T-cell activation and can produce an array of cytokines. Disturbances of peripheral B-cell homeostasis together with the formation of ectopic lymphoid neogenesis within the inflamed synovium appears to be a characteristic of patients with RA. Enhanced generation of memory B cells and autoreactive plasma cells producing IgM-RF and ACPA-IgG antibodies together with formation of immune complexes contribute to the maintenance of RA, whereas treatment with B-cell-directed anti-CD20 and CLTA4-Ig therapy provides clinical benefit.

Download Full-text

Activated CD4+CD25+ T cells selectively kill B lymphocytes

Blood ◽

10.1182/blood-2005-11-4502 ◽

2006 ◽

Vol 107 (10) ◽

pp. 3925-3932 ◽

Cited By ~ 305

Author(s):

Dong-Mei Zhao ◽

Angela M. Thornton ◽

Richard J. DiPaolo ◽

Ethan M. Shevach

Keyword(s):

Cell Proliferation ◽

T Cells ◽

Cell Death ◽

B Cells ◽

B Cell ◽

T Cell Activation ◽

Fas Ligand ◽

Cell Function ◽

Cell Contact ◽

Dependent Manner

The suppressive capacity of naturally occurring mouse CD4+CD25+ T cells on T-cell activation has been well documented. The present study is focused on the interaction of CD4+CD25+ T cells and B cells. By coculturing preactivated CD4+CD25+ T cells with B cells in the presence of polyclonal B-cell activators, we found that B-cell proliferation was significantly suppressed. The suppression of B-cell proliferation was due to increased cell death caused by the CD4+CD25+ T cells in a cell-contact–dependent manner. The induction of B-cell death is not mediated by Fas–Fas ligand pathway, but surprisingly, depends on the up-regulation of perforin and granzymes in the CD4+CD25+ T cells. Furthermore, activated CD4+CD25+ T cells preferentially killed antigen-presenting but not bystander B cells. Our results demonstrate that CD4+CD25+ T cells can act directly on B cells and suggest that the prevention of autoimmunity by CD4+CD25+ T cells can be explained, at least in part, by the direct regulation of B-cell function.

Download Full-text

Complement receptors regulate differentiation of bone marrow plasma cell precursors expressing transcription factors Blimp-1 and XBP-1

Journal of Experimental Medicine ◽

10.1084/jem.20042239 ◽

2005 ◽

Vol 201 (6) ◽

pp. 993-1005 ◽

Cited By ~ 57

Author(s):

Dominique Gatto ◽

Thomas Pfister ◽

Andrea Jegerlehner ◽

Stephen W. Martin ◽

Manfred Kopf ◽

...

Keyword(s):

Bone Marrow ◽

B Cells ◽

B Cell ◽

Plasma Cell ◽

Cell Activation ◽

Plasma Cells ◽

Antibody Responses ◽

Complement Receptors ◽

Essentially Normal ◽

Bone Marrow Plasma

Humoral immune responses are thought to be enhanced by complement-mediated recruitment of the CD21–CD19–CD81 coreceptor complex into the B cell antigen receptor (BCR) complex, which lowers the threshold of B cell activation and increases the survival and proliferative capacity of responding B cells. To investigate the role of the CD21–CD35 complement receptors in the generation of B cell memory, we analyzed the response against viral particles derived from the bacteriophage Qβ in mice deficient in CD21–CD35 (Cr2−/−). Despite highly efficient induction of early antibody responses and germinal center (GC) reactions to immunization with Qβ, Cr2−/− mice exhibited impaired antibody persistence paralleled by a strongly reduced development of bone marrow plasma cells. Surprisingly, antigen-specific memory B cells were essentially normal in these mice. In the absence of CD21-mediated costimulation, Qβ-specific post-GC B cells failed to induce the transcriptional regulators Blimp-1 and XBP-1 driving plasma cell differentiation, and the antiapoptotic protein Bcl-2, which resulted in failure to generate the precursor population of long-lived plasma cells residing in the bone marrow. These results suggest that complement receptors maintain antibody responses by delivery of differentiation and survival signals to precursors of bone marrow plasma cells.

Download Full-text

B-cell dysfunction following human bone marrow transplantation: functional-phenotypic dissociation in the early posttransplant period

Blood ◽

10.1182/blood.v74.2.777.777 ◽

1989 ◽

Vol 74 (2) ◽

pp. 777-785 ◽

Cited By ~ 11

Author(s):

JM Kagan ◽

RE Champlin ◽

A Saxon

Keyword(s):

Bone Marrow ◽

Bone Marrow Transplantation ◽

B Cells ◽

Cell Surface ◽

B Cell ◽

Marrow Transplantation ◽

Cell Activation ◽

High Rate ◽

Normal Surface ◽

Surface Phenotype

Abstract We investigated the defect in humoral immunity that occurs following bone marrow transplantation (BMT). B cells from BMT recipients were tested for their ability to undergo the sequential steps of activation (RNA synthesis on stimulation with anti-mu or PMA), proliferation (DNA synthesis on stimulation with anti-mu plus B cell growth factor [BCGF], phorbol myristate acetate [PMA], or Staphylococcus aureus Cowan I [SAC] strain bacteria) and differentiation (Ig synthesis stimulated by T cell replacing factor [TRF]). B-cell maturation-associated cell surface markers were simultaneously investigated. “Early” (less than 10 months) posttransplant patients demonstrated defective B-cell activation and also failed to undergo normal proliferation and differentiation. Despite their functional impairment, the early patients' B cells displayed an “activated” phenotype with increased proportions of B cells displaying CD23 (a BCGF receptor) and decreased proportions of Leu 8+ B cells. Furthermore, these patients were uniquely distinguished by the fact that their B cells only weakly (if at all) expressed the CD19 antigen. In contrast, B cells from “late” patients (greater than or equal to 10 months post-BMT) activated and proliferated normally and displayed a normal cell surface phenotype, yet were unable to differentiate to high rate Ig secretion with TRF. Our results suggest a phenotype/function dissociation in early posttransplant period. With time, B cells in BMT patients acquire a normal surface phenotype and can activate and proliferate normally, yet still demonstrate a block in terminal differentiation.

Download Full-text

Role for low-affinity receptor for IgE (CD23) in normal and leukemic B- cell proliferation

Blood ◽

10.1182/blood.v84.6.1881.1881 ◽

1994 ◽

Vol 84 (6) ◽

pp. 1881-1886 ◽

Cited By ~ 42

Author(s):

S Fournier ◽

M Rubio ◽

G Delespesse ◽

M Sarfati

Keyword(s):

Cell Proliferation ◽

B Cells ◽

B Cell ◽

Cell Activation ◽

Early Stage ◽

Lymphocytic Leukemia ◽

Interleukin 4 ◽

B Cell Activation ◽

Type B ◽

Cd23 Expression

Abstract CD23 gene is overexpressed and abnormally regulated in the most frequent adult leukemic disorder, B chronic lymphocytic leukemia (B- CLL). Switch on and off in the upregulation of surface CD23 expression consistently occurs in the early stage of normal B-cell activation, suggesting a key role for CD23 in this process. We show here that, after ligation of mlg in the presence of interleukin-4, the increase of CD23 protein precedes B-cell DNA synthesis and mainly results from the strong induction of CD23 type-B isoform. Exposure of normal B cells to conventional or phosphorothioate-derivatized CD23 antisense oligonucleotides (predominantly type B) significantly augments B-cell proliferation induced by antigen receptor stimulation or direct contact with activated T cells. Unexpectedly, CD23 antisense, but not sense, oligonucleotides specifically enhance rather than suppress CD23 expression on B cells. Finally, a selective increase in CD23 type-B expression provokes the entry of resting (Go) CLL B cells into G1 and S phase of the cell cycle in the absence of any other stimulus, whereas it synergizes with tumor necrosis factor-alpha to increase the number of activated B cells. These results provide compelling evidence that CD23 represents an important molecule directly involved in the process of normal or leukemic B-cell activation and growth.

Download Full-text