Transitional B cells: step by step towards immune competence

AbstractFollicular 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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OP0186 CHANGES IN CIRCULATING B CELL LEVELS AND IMMUNOPHENOTYPE ARE ASSOCIATED WITH DEVELOPMENT OF ARTHRITIS FOLLOWING TREATMENT WITH CHECKPOINT INHIBITORS

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2021-eular.908 ◽

2021 ◽

Vol 80 (Suppl 1) ◽

pp. 112.2-113

Author(s):

M. Gatto ◽

S. Bjursten ◽

C. Jonell ◽

C. Jonsson ◽

S. Mcgrath ◽

...

Keyword(s):

Flow Cytometry ◽

B Cells ◽

Adverse Events ◽

B Cell ◽

Mononuclear Cells ◽

Checkpoint Inhibitors ◽

Therapy Monitoring ◽

Cell Subset ◽

Peripheral Blood Mononuclear ◽

Transitional B Cells

Background:Inflammatory arthritis (IA) is frequent among rheumatic side effects induced by checkpoint inhibitor (CPI) therapy for metastatic malignancies1. While T cells are likely to sustain the inflammatory process2, fewer data are available concerning the role of B cells3.Objectives:To investigate the phenotype of circulating B cells in patients who develop CPI-induced IA (CPI-IA) and to compare it with features of B cells in patients not developing immune-related adverse events (irAE) upon CPI treatment.Methods:B cell subsets at baseline (before CPI initiation) and during CPI treatment were analyzed in CPI-IA patients and in patients receiving CPI but who did not develop irAE (non-irAE). Peripheral blood mononuclear cells (PBMC) were analyzed by flow cytometry and B cells were identified as CD19+ and divided into naïve (CD27-IgD+), memory (CD27+IgD+/-), double negative (CD27-IgD-) and transitional (CD10+CD24+CD38+/hi) B cells. Levels of CD21, an activation marker on transitional B cells, were also analyzed. Non-parametric tests were used for analysis of differences between groups.Results:Six CPI-IA and 7 non-irAE patients matched for age, gender and CPI treatment were included, who had received CPI treatment due to metastatic melanoma. Flow cytometry revealed a significant increase of circulating B cells (p=0.002) (Figure 1A) and especially of transitional B cells in CPI-IA patients vs. non-irAE (median %, range: 7.8 (4.5-11.4) vs. 3.2 (1.6-4.3),p=0.007) (Figure 1B), while no remarkable changes were seen across other subsets. Transitional B cell levels significantly decreased from active to quiescent CPI-IA in all patients (p=0.008). In two CPI-IA patients for whom baseline sampling was available, the increase of transitional levels occurred early after CPI treatment and before CPI-IA onset. Levels of expression of CD21 on transitional B cells were increased in CPI-IA vs. non-irAE (p=0.01).Conclusion:Transitional B cells are expanded in CPI-IA patients and seem to increase early after start of CPI therapy. Monitoring this B cell subset might lead to closer follow-up and earlier diagnosis of CPI-IA.References:[1]Ramos-Casals M, Brahmer JR, Callahan MK, et al. Immune-related adverse events of checkpoint inhibitors. Nat Rev Dis Primers 2020;6:38[2]Murray-Brown W, Wilsdon TD, Weedon H, et al. Nivolumab-induced synovitis is characterized by florid T cell infiltration and rapid resolution with synovial biopsy-guided therapy. J Immunother Cancer 2020;8:e000281[3]Das R, Bar N, Ferreira M, et al. Early B cell changes predict autoimmunity following combination immune checkpoint blockade. J Clin Invest. 2018;128:715-2Disclosure of Interests:None declared

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AB0025 B-CELL SUBSETS AS ADDITIONAL DIAGNOSTIC TOOL FOR PRIMARY SJOGREN’S SYNDROME AND SYSTEMIC LUPUS ERYTHEMATOSUS

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2020-eular.5332 ◽

2020 ◽

Vol 79 (Suppl 1) ◽

pp. 1315.1-1316

Author(s):

S. Benevolenskaya ◽

I. Kudryavtsev ◽

M. Serebriakova ◽

I. Grigor’eva ◽

A. Budkova ◽

...

Keyword(s):

B Cells ◽

Discriminant Analysis ◽

B Cell ◽

Sjögren’S Syndrome ◽

Sjögren's Syndrome ◽

Sjogren’S Syndrome ◽

Sjogren's Syndrome ◽

Transitional B Cells ◽

B Cell Subsets ◽

Sjögren‘S Syndrome

Background:Systemic lupus erythematosus (SLE) and primary Sjögren’s syndrome (pSS) are chronic complex disorders with an autoimmune background, multifactorial etiology, multiple circulating antinuclear antibodies and damage of various organs. SLE and pSS have several similar clinical and serological aspects; likewise, SLE and Sjögren’s syndrome may coexist (so-called secondary Sjögren’s syndrome). However, applied classification criteria do not differentiate SLE and pSS. It is known that humoral immunity plays significant part in pathogenesis of those diseases; hereby, we can expect imbalances in B cell subset frequencies during SLE and pSS.Objectives:To investigate clinical utility of B cell subsets in distinguish SLE and pSS during diagnosis.Methods:A total of 25 SLE patients, 25 SS patients and 49 healthy volunteers (HV) were included in the study. The diagnosis of SLE was performed according to the 2019 EULAR – ACR classification criteria, the diagnosis of pSS - according to the 2016 EULAR – ACR criteria. Phenotyping of blood B cell subsets was done using flow cytometry. Total peripheral blood B cells were identified using CD19 expression, distinct B cell subsets were characterized by IgD, CD38 and CD27 expression. All of the statistical analysis of data was performed with STATISTICA Version 12.0 Inc. (USA).Results:We evaluated the percentages of circulating B-cell subsets using three major classification schemes based on the relative co-expression of either IgD/CD38 (so-called “Bm1-Bm5” classification), IgD/CD27 and CD38/CD27. A discriminant analysis was performed for all B cell classifications. Analysis of CD38 and CD27 co-expression demonstrated most significant separation between patients with SLE and pSS (fig. 1). Moreover, discriminant analysis carried out by using a forward stepwise model demonstrated that the top significance was documented while assessing the percentage of plasmoblasts (CD27hiCD38hi), resting memory B-cells (CD27dimCD38low), mature active B-cells (CD27dimCD38dim), naive mature B-cells (CD27dimCD38low), as well as counting the absolute numbers of transitional B-cells (CD27lowCD38hi), model percent correct was 78,6% (p <0,05, tab.1).Figure 1.Graphic distribution of SLE and pSS patients as well as HV analyzed by discriminant analysis.Conclusion:B cell subsets might provide a useful diagnostic tool for distinction SLE and pSS. More research needed to investigate clinical value of B-cell subsets in autoimmune rheumatic diseases.Table 1.Peripheral B-cell subset composition in SLE and SS patients vs. HV group assessed by discriminant analysis.ParameterF-testp-levelPlasmoblasts (CD27hiCD38hi), %7,93<0.001Resting memory B-cells (CD27dimCD38low), %13,72<0.001Transitional B-cells (CD27lowCD38hi)29,74<0.001Mature active B-cells (CD27dimCD38dim), %5,20<0.001Naive mature B-cells (CD27dimCD38low), %3,100.049Double negative (CD27lowCD38low), %1,980,14Resting memory B-cells (CD27dimCD38low)1,020,36Double negative (CD27lowCD38low)2,320,10Plasmoblasts (CD27hiCD38hi)1,020,36Naive mature B-cells (CD27dimCD38low)1,030,36Mature active B-cells (CD27dimCD38dim)1,020,36Transitional B-cells (CD27lowCD38hi), %1,030,36Disclosure of Interests:None declared

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Cutting Edge: Endogenous IFN-β Regulates Survival and Development of Transitional B Cells

The Journal of Immunology ◽

10.4049/jimmunol.1700888 ◽

2017 ◽

Vol 199 (8) ◽

pp. 2618-2623 ◽

Cited By ~ 16

Author(s):

Jennie A. Hamilton ◽

Qi Wu ◽

PingAr Yang ◽

Bao Luo ◽

Shanrun Liu ◽

...

Keyword(s):

B Cells ◽

Cutting Edge ◽

Transitional B Cells ◽

Survival And Development

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Immune Response to SARS-CoV-2 Vaccine in 2 Men

International Archives of Allergy and Immunology ◽

10.1159/000520046 ◽

2021 ◽

pp. 1-10

Author(s):

Sudhir Gupta ◽

Houfen Su ◽

Sudhanshu Agrawal

Keyword(s):

T Cells ◽

B Cells ◽

Cd8 T Cells ◽

Specific Response ◽

Igg Antibodies ◽

Marginal Zone B Cells ◽

Transitional B Cells ◽

T Subsets ◽

B Cell Subsets ◽

Regulatory Lymphocytes

Introduction: In the trials of corona virus vaccines, detailed analyses of subsets of lymphocytes were not carried out. We present perhaps the most comprehensive immunological analysis of 29 subsets of B and T cells in 2 healthy subjects receiving 2 doses of the Pfizer SARS-CoV-2 (COVID-19) vaccine. Methods: Analyses were performed prior to vaccination, 3 weeks following the 1st dose, and 4 weeks following the 2nd dose. Total, naïve (TN), and different memory and effector subsets (TCM, TEM, and TEMRA) of CD4+ and CD8+ T cells; SARS-CoV-2 spike protein-specific tetramer+, and cytotoxic CD8+ T; subsets of T follicular cells (TFH, TFH1, TFH2, TFH1/TFH17, and TFH17); B-cell subsets (mature B cells, naive B cells, transitional B cells, marginal zone B cells, class-switched memory B cells, germinal center B cells, and CD21low B cells), and plasmablasts; and regulatory lymphocytes (CD4+ Treg, CD8+ Treg, Breg, and TFR cells) were evaluated with specific monoclonal antibodies by flow cytometry. Results: A lack of COVID-19 IgG antibodies after the 1st dose in one of 2 subjects was associated with increased regulatory lymphocytes and decreased plasmablasts. Seroconversion after the 2nd dose in this subject was associated with decreased TFR cells and increased plasmablasts. In both subjects, CD4 TEM and CD8 TCM were markedly increased following the 2nd dose. TFH1 and regulatory lymphocytes were increased (except Breg) following the 1st dose. A striking increase in SARS-CoV-2-specific CD8+ T cells was observed following the 2nd dose. Conclusion: Our data support the need for 2nd dose of vaccine to induce strong SARS-CoV-2 CD8 T-cell specific response and generation of memory subsets of CD4+ and CD8+ T cells. Regulatory lymphocytes appear to play a role in the magnitude of response.

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Marginating transitional B cells modulate neutrophils in the lung during inflammation and pneumonia

Journal of Experimental Medicine ◽

10.1084/jem.20210409 ◽

2021 ◽

Vol 218 (9) ◽

Author(s):

John Podstawka ◽

Sarthak Sinha ◽

Carlos H. Hiroki ◽

Nicole Sarden ◽

Elise Granton ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Regulatory Networks ◽

Vascular Inflammation ◽

Transitional B Cells ◽

Pulmonary Capillaries ◽

Life Threatening ◽

B Cell Subsets

Pulmonary innate immunity is required for host defense; however, excessive neutrophil inflammation can cause life-threatening acute lung injury. B lymphocytes can be regulatory, yet little is known about peripheral transitional IgM+ B cells in terms of regulatory properties. Using single-cell RNA sequencing, we discovered eight IgM+ B cell subsets with unique gene regulatory networks in the lung circulation dominated by transitional type 1 B and type 2 B (T2B) cells. Lung intravital confocal microscopy revealed that T2B cells marginate in the pulmonary capillaries via CD49e and require CXCL13 and CXCR5. During lung inflammation, marginated T2B cells dampened excessive neutrophil vascular inflammation via the specialized proresolving molecule lipoxin A4 (LXA4). Exogenous CXCL13 dampened excessive neutrophilic inflammation by increasing marginated B cells, and LXA4 recapitulated neutrophil regulation in B cell–deficient mice during inflammation and fungal pneumonia. Thus, the lung microvasculature is enriched in multiple IgM+ B cell subsets with marginating capillary T2B cells that dampen neutrophil responses.

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Altered BCR and TLR signals promote enhanced positive selection of autoreactive transitional B cells in Wiskott-Aldrich syndrome

Journal of Experimental Medicine ◽

10.1084/jem.20150585 ◽

2015 ◽

Vol 212 (10) ◽

pp. 1663-1677 ◽

Cited By ~ 41

Author(s):

Nikita S. Kolhatkar ◽

Archana Brahmandam ◽

Christopher D. Thouvenel ◽

Shirly Becker-Herman ◽

Holly M. Jacobs ◽

...

Keyword(s):

B Cells ◽

Positive Selection ◽

B Cell ◽

Heavy Chain ◽

High Throughput Sequencing ◽

Cell Stage ◽

Wiskott Aldrich Syndrome ◽

Transitional B Cells ◽

Selection Of

Wiskott-Aldrich syndrome (WAS) is an X-linked immunodeficiency disorder frequently associated with systemic autoimmunity, including autoantibody-mediated cytopenias. WAS protein (WASp)–deficient B cells have increased B cell receptor (BCR) and Toll-like receptor (TLR) signaling, suggesting that these pathways might impact establishment of the mature, naive BCR repertoire. To directly investigate this possibility, we evaluated naive B cell specificity and composition in WASp-deficient mice and WAS subjects (n = 12). High-throughput sequencing and single-cell cloning analysis of the BCR repertoire revealed altered heavy chain usage and enrichment for low-affinity self-reactive specificities in murine marginal zone and human naive B cells. Although negative selection mechanisms including deletion, anergy, and receptor editing were relatively unperturbed, WASp-deficient transitional B cells showed enhanced proliferation in vivo mediated by antigen- and Myd88-dependent signals. Finally, using both BCR sequencing and cell surface analysis with a monoclonal antibody recognizing an intrinsically autoreactive heavy chain, we show enrichment in self-reactive cells specifically at the transitional to naive mature B cell stage in WAS subjects. Our combined data support a model wherein modest alterations in B cell–intrinsic, BCR, and TLR signals in WAS, and likely other autoimmune disorders, are sufficient to alter B cell tolerance via positive selection of self-reactive transitional B cells.

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