scholarly journals A splenic IgM memory subset with antibacterial specificities is sustained from persistent mucosal responses

2018 ◽  
Vol 215 (8) ◽  
pp. 2035-2053 ◽  
Author(s):  
Simon Le Gallou ◽  
Zhicheng Zhou ◽  
Lan-Huong Thai ◽  
Remi Fritzen ◽  
Alba Verge de los Aires ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Bacterial Infections ◽  
Plasma Cells ◽  
Memory B Cells ◽  
Endogenous Retroviruses ◽  
Lymphoid Tissues ◽  
Gut Flora ◽  
Protective Capacity ◽  
B Cell Subsets

To what extent immune responses against the gut flora are compartmentalized within mucosal tissues in homeostatic conditions remains a much-debated issue. We describe here, based on an inducible AID fate-mapping mouse model, that systemic memory B cell subsets, including mainly IgM+ B cells in spleen, together with IgA+ plasma cells in spleen and bone marrow, are generated in mice in the absence of deliberate immunization. While the IgA component appears dependent on the gut flora, IgM memory B cells are still generated in germ-free mice, albeit to a reduced extent. Clonal relationships and renewal kinetics after anti-CD20 treatment reveal that this long-lasting splenic population is mainly sustained by output of B cell clones persisting in mucosal germinal centers. IgM-secreting hybridomas established from splenic IgM memory B cells showed reactivity against various bacterial isolates and endogenous retroviruses. Ongoing activation of B cells in gut-associated lymphoid tissues thus generates a diversified systemic compartment showing long-lasting clonal persistence and protective capacity against systemic bacterial infections.

Impact of Autologous Dendritic Cell Immunotherapy (Arcelis™) on B Cell Subsets in HIV-1-Infected Subjects Receiving Antiretroviral Therapy

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 80-80
Author(s):  
Mohamed-Rachid Boulassel ◽  
Bader Yassine-Diab ◽  
Don Healey ◽  
Charles Nicolette ◽  
Rafick-Pierre Sékaly ◽  
...  
Keyword(s):  
T Cell ◽  
B Cells ◽  
Immune Responses ◽  
B Cell ◽  
Plasma Cells ◽  
Cell Subset ◽  
Cd8 T Cell ◽  
Memory B Cells ◽  
B Cell Subsets ◽  
Hiv 1

Abstract We demonstrated the enhancement of CD8-specific responses following the administration of an immune-based therapy consisting of dendritic cells (DC) electroporated with autologous amplified HIV-1 RNA and CD40 ligand (CD40 L) RNA manufactured by the Arcelis™ process in HIV patients receiving antiretroviral therapy (ART). We conducted a sub study on circulating B cell populations to further assess changes induced by this autologous DC therapy as CD40L is a major B cell co-stimulatory factor. To this end, we assessed B cell subset changes in relation to the proliferative capacity of CD4+ and CD8+ T cells response to DC targets containing the 4 HIV-1 antigens (Gag, Vpr, Rev, Nef). The co-expression of CD19, CD38, IgD, CD10, CD23, CD27, CD5, and CD138 were analyzed by multi-parametric flow cytometry to assess circulating B cell subsets such as naïve resting B-cells (Bm1), activated naïve B cells (Bm2), GC founder cells (Bm2’), centroblasts and centrocytes (Bm3 and Bm4), early memory B cells (eBm5), memory B cells (Bm5), IgD memory cells, plasma cells, and B-1 cells. Changes in B cells subsets were analyzed before and after the four intradermal injections of this immunotherapeutic product containing 1.2 × 107 DC. Ten ART treated subjects with undetectable viral load (< 50 copies/ml), median CD4+ count of 440 cells/μl (range: 316–1102), and with a CD4+ nadir > 200 cells/μl were studied. Throughout the study, no significant changes in CD4+ cell count, CD4/CD8 ratio, and no viral blips were noticed. The percentage of total B cells, Bm1, Bm2, Bm2′, eBm5, IgD memory, plasma cells, and B-1 cell subsets did not significantly change. However, a decrease in the percentage of Bm3 and Bm4 cells was found (0.36 [0.06–0.86] versus 0.11 [0.04–0.36]; P=0.05). Conversely, an important increase in the Bm5 cell subset was evidenced (10.4 [1.6–24.2] versus 18.1 [5.1–27.5]; P=0.005) suggesting a proliferation of B memory cells induced by DC immunization. In addition, the multifunctional and polyvalent CD8+ T cell proliferative responses to the 4 HIV genes used in this immunotherapy were noticed in 8 out of 9 subjects available for analysis and characterized by an effector memory phenotype. No CD4+ T cell immune responses were detected, consistent with the endogenous HLA class I loading of the antigens. Collectively, these results indicate that this immunotherapy induces an increase in the B memory cell population in the absence of inducing any clinically apparent autoimmunity along with strong HIV specific multifunctional CD8+ T cell specific immune responses.

Reduced Circulating Memory B-Cells Account for Humoral Immune Defects in Multiple Myeloma, Associated with Infective Risk and Poor Vaccination Responses

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3393-3393
Author(s):  
Jonathan Carmichael ◽  
Clive R Carter ◽  
Christopher Parrish ◽  
Charlotte Kallmeyer ◽  
Sylvia Feyler ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Bacterial Infections ◽  
Memory B Cells ◽  
Antibody Responses ◽  
Progressive Reduction ◽  
Cell Numbers ◽  
Humoral Immune ◽  
Transitional B Cells ◽  
B Cell Subsets

Abstract Multiple myeloma (MM) is characterized by an increased risk of infection due to the immunosuppressive effect of the disease and conjointly of therapy. Furthermore, there is impaired responses to vaccination to counter the infection risk. The factors that underpin defective B-cell homeostasis and effective humoral immunity are not clear, nor are the extent of the defects. Also, the level of impaired humoral immunity in MGUS is not fully understood. The aim of this study was to delineate the circulating B-cell populations and recall antibody responses in patients with MGUS & MM, compared to age-matched controls, correlating with the responsiveness to vaccinations, incidence of infective complications and concomitant therapy. We performed comprehensive B-cell immunophenotyping by multi-parameter flow cytometry of peripheral blood samples from patients with MGUS (n=16), asymptomatic MM (n=18) and MM (n=108) with a median age of 63 years (range 38-94) comparing them to age-matched controls (n=9). B-cell subsets included naïve (CD19+CD27-), memory (CD19+CD27+; non-switch CD19+IgD+CD27+, switch CD19+IgD-CD27+), transitional (CD19+CD27-CD24hiCD38hi) & regulatory (CD19+CD27+CD24hi) B-cells. Serum uninvolved total IgG, IgM & IgA levels along with vaccine-specific antibody responses were analysed. There is a progressive decrease in the uninvolved immunoglobulin classes with significant reduction in total IgA (p=0.006) and IgM levels (p=0.007) in aMM/MM compared to MGUS & control (Figure 1). When anti-pneumococcal antibodies were measured, only 30% of aMM/MM patients had adequate protective levels compared to 79% of age-matched controls, with 40% of aMM/MM patients with inadequate levels experiencing recurrent respiratory tract infections compared to 25% of aMM/MM patients with adequate proactive antibodies. Patients with MGUS, aMM and MM have lower total B-cell numbers compared to controls (1-way ANOVA p=0.004; Figure 1). The reduction in B-cell numbers were primarily the consequence of reduced memory B-cells (percentage and absolute 1-way ANOVA p<0.0001), noted in both MGUS and aMM/MM but a progressive reduction with increasing disease activity (MGUS>aMM>MM). Furthermore, a correlation with total IgG levels & memory B-cell numbers is evident (r2=-0.053) & progressive reduction in memory B-cell numbers is seen with advancing cycles of therapy. The ratio of switch:non-switch memory B-cells is unaltered (control 1.05, MGUS 0.53, aMM 1.41 & MM 1.49; 1-way ANOVA p=ns). Conversely, there is a compensatory increase in the percentage of transitional B-cells when increasing disease stage is compared to controls (control 7.38% (95%ci 4.9,9.9) vs MGUS 14.0% (95%ci 7.4, 20.7) vs aMM 14.95% (95%ci 8, 21.9); 1-way ANOVA p<0.001) but a reduction is noted in MM (5.82%, 95%ci 4.5,7.2; p<0.0001), primarily being driven by sequential lines of therapy. As a consequence, the ratio of Memory:transitional B-cells is significantly reduced in aMM/MM compared to MGUS & controls (control 10.35, MGUS 20.46, aMM 7.74 & MM 4.57; 1-way ANOVA p=0.006), associated with increasing incidence of bacterial infections. A non-significant correlation is seen between transitional B-cells and total uninvolved immunoglobulin levels and with recall responses to vaccinations. There is a progressive decrease in the CD19+CD27+CD24hi B-cell subset between control and plasma cell dyscrasias (control 20.4% (95%ci 15.5,25.2), MGUS 14.0% (95%ci 7.4, 20.7), aMM 14.95% (95%ci 8, 21.9) & MM 5.82%, 95%ci 4.5,7.2; p<0.0001), primarily being driven by sequential lines of therapy and associated with increased incidence of infection. This study illustrates that patients with myeloma demonstrate reduced total circulating B-cells primarily as a consequence of reduced memory B-cells, associated with reduced immunoglobulin and recall antibody responses. This is associated with increased incidence of bacterial infections and is worsened by sequential exposure to lymphodepleting therapies. Of particular importance is the identified aberration in B-cell subsets seen in MGUS compared with age-matched control, indicative of humoral immune dysregulation highlighting that MGUS may not be an immunologically inert disorder. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

scholarly journals Memory B Cells in Pregnancy Sensitization

2021 ◽  
Vol 12 ◽  
Author(s):  
Anoma Nellore ◽  
John T. Killian ◽  
Paige M. Porrett
Keyword(s):  
B Cells ◽  
B Cell ◽  
Molecular Mechanisms ◽  
Memory B Cells ◽  
Lymphoid Tissues ◽  
Potential Contribution ◽  
Follicular Helper ◽  
B Cell Subsets ◽  
The Impact ◽  
In Pregnancy

Memory B cells play an important role in immunity to pathogens as these cells are poised to rapidly differentiate into antibody-secreting cells upon antigen re-encounter. Memory B cells also develop over the course of HLA-sensitization during pregnancy and transplantation. In this review, we discuss the potential contribution of memory B cells to pregnancy sensitization as well as the impact of these cells on transplant candidacy and outcomes. We start by summarizing how B cell subsets are altered in pregnancy and discuss what is known about HLA-specific B cell responses given our current understanding of fetal antigen availability in maternal secondary lymphoid tissues. We then review the molecular mechanisms governing the generation and maintenance of memory B cells during infection – including the role of T follicular helper cells - and discuss the experimental evidence for the development of these cells during pregnancy. Finally, we discuss how memory B cells impact access to transplantation and transplant outcomes for a range of transplant recipients.

scholarly journals Recovery of Memory B-cell Subsets and Persistence of Antibodies in Convalescent COVID-19 Patients

2021 ◽  
Author(s):  
Anuradha Rajamanickam ◽  
Nathella Pavan Kumar ◽  
Arul Nancy P ◽  
Nandhini Selvaraj ◽  
Saravanan Munisankar ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Neutralizing Antibodies ◽  
Plasma Cells ◽  
Ex Vivo ◽  
Cell Subset ◽  
Memory B Cells ◽  
Memory B Cell ◽  
Immature B Cells ◽  
B Cell Subsets

It is essential to examine the longevity of the defensive immune response engendered by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. We examined the SARS-CoV-2-specific antibody responses and ex vivo memory B-cell subsets in seven groups of individuals with COVID-19 classified based on days since reverse-transcription polymerase chain reaction confirmation of SARS-CoV-2 infection. Our data showed that the levels of IgG and neutralizing antibodies started increasing from days 15 to 30 to days 61 to 90, and plateaued thereafter. The frequencies of naive B cells and atypical memory B cells decreased from days 15 to 30 to days 61 to 90, and plateaued thereafter. In contrast, the frequencies of immature B cells, classical memory B cells, activated memory B cells, and plasma cells increased from days 15 to 30 to days 61 to 90, and plateaued thereafter. Patients with severe COVID-19 exhibited increased frequencies of naive cells, atypical memory B cells, and activated memory B cells, and lower frequencies of immature B cells, central memory B cells, and plasma cells when compared with patients with mild COVID-19. Therefore, our data suggest modifications in memory B-cell subset frequencies and persistence of humoral immunity in convalescent individuals with COVID-19.

scholarly journals Toll-Like Receptor Homolog CD180 Expression Is Diminished on Natural Autoantibody-Producing B Cells of Patients with Autoimmune CNS Disorders

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Zsófia Hayden ◽  
Szabina Erdő-Bonyár ◽  
Beáta Bóné ◽  
Noémi Balázs ◽  
Kornélia Bodó ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Peripheral Blood ◽  
Bacterial Infections ◽  
Citrate Synthase ◽  
Memory B Cells ◽  
Igg Antibody ◽  
Autoantibody Production ◽  
B Cell Subsets ◽  
Natural Autoantibody

Purpose. Decreased expression of TLR homolog CD180 in peripheral blood B cells and its potential role in antibody production have been described in autoimmune diseases. Effectiveness of anti-CD20 therapy in neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS) strengthens the role of B cells in the pathogenesis. Therefore, we aimed to investigate the CD180 expression of peripheral blood B cell subsets in NMOSD and MS patients and analyze the levels of natural anti-citrate synthase (CS) IgG autoantibodies and IgG antibodies induced by bacterial infections reported to play a role in the pathogenesis of NMOSD or MS. Methods. We analyzed the distribution and CD180 expression of peripheral blood B cell subsets, defined by CD19/CD27/IgD staining, and measured anti-CS IgM/G natural autoantibody and antibacterial IgG serum levels in NMOSD, RRMS, and healthy controls (HC). Results. We found decreased naïve and increased memory B cells in NMOSD compared to MS. Among the investigated four B cell subsets, CD180 expression was exclusively decreased in CD19+CD27+IgD+ nonswitched (NS) memory B cells in both NMOSD and MS compared to HC. Furthermore, the anti-CS IgM natural autoantibody serum level was lower in both NMOSD and MS. In addition, we found a tendency of higher anti-CS IgG natural autoantibody levels only in anti-Chlamydia IgG antibody-positive NMOSD and MS patients. Conclusions. Our results suggest that reduced CD180 expression of NS B cells could contribute to the deficient natural IgM autoantibody production in NMOSD and MS, whereas natural IgG autoantibody levels show an association with antibacterial antibodies.

Mirna Profiling Reveals Specific Patterns for Normal B Cell Subsets and B Cell Lymphomas with a Unique Burkitt Lymphoma Profile

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3763-3763
Author(s):  
Jan-Lukas Robertus ◽  
Geert Harms ◽  
Rogier Reijmers ◽  
Steven Pals ◽  
Yolanthe Swart ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Hierarchical Clustering ◽  
Burkitt Lymphoma ◽  
Plasma Cells ◽  
Memory B Cells ◽  
Fold Change ◽  
Differentially Expressed ◽  
Differentially Expressed Mirnas ◽  
B Cell Subsets

Abstract Abstract: MicroRNAs (miRNAs) are small (22–23nt) noncoding RNAs, which negatively regulate gene expression by inhibiting protein translation. MiRNAs play an important role in various cellular processes such as hematopoiesis. Deregulated expression is associated with development of B-cell lymphomas. The aim of this study was to define miRNA expression profiles to identify differentially expressed miRNAs in normal B cell subsets and malignancies derived from these subsets. Using Agilent Human miRNA microarrays the expression levels of 556 miRNAs were determined in 7 Mantle cell lymphoma (MCL), 7 Follicular lymphoma (FL), 7 paediatric Burkitt lymphoma (BL) and 13 Chronic lymphocytic lymphoma (CLL; 8 ZAP70 pos and 5 ZAP70 neg) cases, as well as in naïve, germinal center (GC), memory B cells and plasma cells obtained from 3 paediatric tonsils. Median normalisation was performed on all array data using GeneSpring GX 9.0.5. Differentially expressed miRNAs were defined by at least a four fold difference using ANOVA (p<0.05). Quantitive (q)RT-PCR was used for validation of the arrays. In the normal B-cell subsets 23 differentially expressed miRNAs were found with a four fold difference. Hierarchical clustering revealed a distinct pattern of these subsets. Specifically in GC B cells miR-15b, miR-17-5p and its seed family member miR- 106a were upregulated in comparison to the naïve, memory B cells and plasma cells. MiR-150, miR-221 and miR-222 were downregulated. Only miR-146a was significantly differentially expressed between naïve and memory B cell subsets. In the lymphoma cases a total of 59 miRNAs were differentially expressed. Hierarchical clustering of these miRNAs grouped all four lymphoma entities separately. ZAP70 positive and negative CLL cases did not cluster separately and none of the miRNAs were differentially expressed. Interestingly, 35 miRNAs were specifically deregulated in the Burkitt lymphomas as compared to MCL, FL and CLL, including miR-18a (up), miR-29a, miR-150, miR-155 and miR-222 (down). Almost all of these miRNAs were found not to be differentially expressed within the normal B cell subsets suggesting that these miRNAs might play a specific role in the biologic behaviour of BL. Comparison of BL to normal GC B cells revealed 15 miRNAs upregulated, including miR-126 and miR-145 (fold change >40), and 79 miRNAs downregulated, including miR-150, miR-155, miR-15, miR-16, miR- 17-5p, miR-21 and miR-222. In comparison with GC B cells FL showed 11 upregulated miRNAs, e.g. miR-143 and miR-145 (fold change >40) and 49 downregulated miRNAs. In comparison with memory B cells 21 miRNAs in the CLL group were upregulated, including miR-143 and miR-145 (fold change > 40) and 83 miRNAs were downregulated. Finally MCL was compared to the naïve B cells and showed 23 upregulated miRNAs with miR-126 showing the highest fold change (>40) and 70 downregulated miRNAs. In conclusion, we have identified specific miRNA profiles for MCL, BL, FL and CLL and also for normal B cell subsets. The differentially expressed miRNA profiles contain several miRNAs that have been shown to be directly or indirectly involved in B cell malignancies but also contain new potentially interesting miRNAs. We also have found several miRNAs that may play a tumor specific role in BL and it can be speculated that miRNAs contained in this profile may target genes related to the more aggressive clinical phenotype of BL.

scholarly journals Dimethyl fumarate as a first- vs second-line therapy in MS

2018 ◽  
Vol 5 (6) ◽  
pp. e508 ◽  
Author(s):  
Elsebeth Staun-Ram ◽  
Eiman Najjar ◽  
Anat Volkowich ◽  
Ariel Miller
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Activation ◽  
Plasma Cells ◽  
Dimethyl Fumarate ◽  
Functional Markers ◽  
Immunomodulatory Effects ◽  
Immune Profile ◽  
Line Therapy ◽  
B Cell Subsets

ObjectiveTo elucidate the immunomodulatory effects of dimethyl fumarate (DMF) on B cells in patients with relapsing MS receiving DMF as a “1st-line” vs “2nd-line” therapy.MethodsB cells were isolated from 43 patients with MS at baseline and after 15-week DMF therapy. Phenotype and functional markers and cytokine profile were assessed by flow cytometry. Analysis included clinical and MRI parameters recorded during a 1-year follow-up.Results1st-line and 2nd-line patients presented several differences in their baseline immune profile, which corresponded with differences in their immunologic response to DMF treatment. DMF reduced the proportions of B cells and CD8 T cells whereas increased monocytes. DMF reduced memory B cells, including plasma cells in 2nd-line patients only, whereas strongly increased transitional B cells. Several IL10+ B-cell subsets and TGFβ+ B cells were increased. Proinflammatory LTα+ and TNFα+ B cells were reduced, while IL4+ B cells elevated, whereas IFNγ+ B cells showed opposite effects in 1st-line and 2nd-line patients. HLA and ICAM-1 expression was increased, but % CD86+ B cells reduced. The expression of B-cell activating factor receptor and the proportion of activated CD69 B cells were increased.ConclusionsDMF is associated with increased transitional and IL10+ and TGFβ+ regulatory B cells and a shift toward a more anti-inflammatory immune profile. Cell activation with reduced costimulatory capacity may induce immune hyporesponsiveness. Carryover effects of preceding therapies in 2nd-line patients and the stage of disease influence the immune profile of the patients and the immunomodulatory effects of DMF.

scholarly journals High-Dimensional Immunophenotyping of Murine T-cell and B-cell Subsets

2020 ◽  
Author(s):  
Kyle T. Mincham ◽  
Jacob D. Young ◽  
Deborah H. Strickland
Keyword(s):  
T Cell ◽  
B Cell ◽  
Plasma Cells ◽  
Effector Memory ◽  
High Dimensional ◽  
Cell Populations ◽  
Lymphoid Tissues ◽  
Murine Models ◽  
Follicular Helper ◽  
B Cell Subsets

Purpose and appropriate sample typesThis 19-parameter, 18-colour flow cytometry panel was designed and optimised to enable the comprehensive and simultaneous immunophenotyping of distinct T-cell and B-cell subsets within murine lymphoid tissues (Table 1). Cellular populations identified by employing this OMIP include 4 major subsets of B-cells (memory, activated, plasma cells and plasmablasts) and 7 major subsets of CD4+ T-cells (naïve, central memory, effector memory, helper, regulatory, follicular helper and follicular regulatory). Staining was performed on freshly isolated splenocytes from 21-day-old neonatal BALB/c mice, however due to the omission of mouse strain-specific markers, this OMIP can be implemented across a range of murine models where in-depth immunophenotyping of the diverse repertoire of T-cell and B-cell populations localised within lymphoid tissues is required.

scholarly journals Potential anti-EBV effects associated with elevated interleukin-21 levels: a case report

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Kristian Assing ◽  
Christian Nielsen ◽  
Marianne Jakobsen ◽  
Charlotte B. Andersen ◽  
Kristin Skogstrand ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Plasma Cell ◽  
Germinal Center ◽  
Plasma Cells ◽  
Cell Formation ◽  
Memory B Cells ◽  
Memory B Cell

Abstract Background Germinal center derived memory B cells and plasma cells constitute, in health and during EBV reactivation, the largest functional EBV reservoir. Hence, by reducing germinal center derived formation of memory B cells and plasma cells, EBV loads may be reduced. Animal and in-vitro models have shown that IL-21 can support memory B and plasma cell formation and thereby potentially contribute to EBV persistence. However, IL-21 also displays anti-viral effects, as mice models have shown that CD4+ T cell produced IL-21 is critical for the differentiation, function and survival of anti-viral CD8+ T cells able to contain chronic virus infections. Case presentation We present immunological work-up (flow-cytometry, ELISA and genetics) related to a patient suffering from a condition resembling B cell chronic active EBV infection, albeit with moderately elevated EBV copy numbers. No mutations in genes associated with EBV disease, common variable immunodeficiency or pertaining to the IL-21 signaling pathway (including hypermorphic IL-21 mutations) were found. Increased (> 5-fold increase 7 days post-vaccination) CD4+ T cell produced (p < 0.01) and extracellular IL-21 levels characterized our patient and coexisted with: CD8+ lymphopenia, B lymphopenia, hypogammaglobulinemia, compromised memory B cell differentiation, absent induction of B-cell lymphoma 6 protein (Bcl-6) dependent peripheral follicular helper T cells (pTFH, p = 0.01), reduced frequencies of peripheral CD4+ Bcl-6+ T cells (p = 0.05), compromised plasmablast differentiation (reduced protein vaccine responses (p < 0.001) as well as reduced Treg frequencies. Supporting IL-21 mediated suppression of pTFH formation, pTFH and CD4+ IL-21+ frequencies were strongly inversely correlated, prior to and after vaccination, in the patient and in controls, Spearman’s rho: − 0.86, p < 0.001. Conclusions To the best of our knowledge, this is the first report of elevated CD4+ IL-21+ T cell frequencies in human EBV disease. IL-21 overproduction may, apart from driving T cell mediated anti-EBV responses, disrupt germinal center derived memory B cell and plasma cell formation, and thereby contribute to EBV disease control.

scholarly journals Complexity of the human memory B-cell compartment is determined by the versatility of clonal diversification in germinal centers

2015 ◽  
Vol 112 (38) ◽  
pp. E5281-E5289 ◽  
Author(s):  
Bettina Budeus ◽  
Stefanie Schweigle de Reynoso ◽  
Martina Przekopowitz ◽  
Daniel Hoffmann ◽  
Marc Seifert ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Clone ◽  
Human Memory ◽  
Memory B Cells ◽  
Sequencing Analysis ◽  
Cell Compartment ◽  
Memory B Cell ◽  
Cell Clones ◽  
B Cell Subsets

Our knowledge about the clonal composition and intraclonal diversity of the human memory B-cell compartment and the relationship between memory B-cell subsets is still limited, although these are central issues for our understanding of adaptive immunity. We performed a deep sequencing analysis of rearranged immunoglobulin (Ig) heavy chain genes from biological replicates, covering more than 100,000 memory B lymphocytes from two healthy adults. We reveal a highly similar B-cell receptor repertoire among the four main human IgM+ and IgG+ memory B-cell subsets. Strikingly, in both donors, 45% of sequences could be assigned to expanded clones, demonstrating that the human memory B-cell compartment is characterized by many, often very large, B-cell clones. Twenty percent of the clones consisted of class switched and IgM+(IgD+) members, a feature that correlated significantly with clone size. Hence, we provide strong evidence that the vast majority of Ig mutated B cells—including IgM+IgD+CD27+ B cells—are post-germinal center (GC) memory B cells. Clone members showed high intraclonal sequence diversity and high intraclonal versatility in Ig class and IgG subclass composition, with particular patterns of memory B-cell clone generation in GC reactions. In conclusion, GC produce amazingly large, complex, and diverse memory B-cell clones, equipping the human immune system with a versatile and highly diverse compartment of IgM+(IgD+) and class-switched memory B cells.

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