Faculty Opinions recommendation of Double-positive CD21+CD27+ B cells are highly proliferating memory cells and their distribution differs in mucosal and peripheral tissues.

The CD45 transmembrane glycoprotein has been shown to be a protein phosphotyrosine phosphatase and to be important in signal transduction in T and B lymphocytes. We have employed gene targeting to create a strain of transgenic mice that completely lacks expression of all isoforms of CD45. The spleens from CD45-null mice contain approximately twice the number of B cells and one fifth the number of T cells found in normal controls. The increase in B cell numbers is due to the specific expansion of two B cell subpopulations that express high levels of immunoglobulin (IgM) staining. T cell development is significantly inhibited in CD45-null animals at two distinct stages. The efficiency of the development of CD4-CD8- thymocytes into CD4+ CD8+ thymocytes is reduced by twofold, subsequently the frequency of successful maturation of the double positive population into mature, single positive thymocytes is reduced by a further four- to fivefold. In addition, we demonstrate that CD45-null thymocytes are severely impaired in their apoptotic response to cross-linking signals via T cell receptor (TCR) in fetal thymic organ culture. In contrast, apoptosis can be induced normally in CD45-null thymocytes by non-TCR-mediated signals. Since both positive and negative selection require signals through the TCR complex, these findings suggest that CD45 is an important regulator of signal transduction via the TCR complex at multiple stages of T cell development. CD45 is absolutely required for the transmission of mitogenic signals via IgM and IgD. By contrast, CD45-null B cells proliferate as well as wild-type cells to CD40-mediated signals. The proliferation of B cells in response to CD38 cross-linking is significantly reduced but not abolished by the CD45-null mutation. We conclude that CD45 is not required at any stage during the generation of mature peripheral B cells, however its loss reveals a previously unrecognized role for CD45 in the regulation of certain subpopulations of B cells.

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Expression of the G-protein--coupled receptor BLR1 defines mature, recirculating B cells and a subset of T-helper memory cells

Blood ◽

10.1182/blood.v84.3.830.830 ◽

1994 ◽

Vol 84 (3) ◽

pp. 830-840 ◽

Cited By ~ 21

Author(s):

R Forster ◽

T Emrich ◽

E Kremmer ◽

M Lipp

Keyword(s):

T Cells ◽

B Cells ◽

Cord Blood ◽

G Protein ◽

Blood Cells ◽

Memory Cells ◽

T Helper ◽

G Protein Coupled Receptor ◽

Color Flow ◽

G Protein Coupled

Abstract The G-protein-coupled receptor BLR1 related to receptors for chemokines and neuropeptides has been identified as the first lymphocyte-specific member of the gene family characterized by seven transmembrane-spanning regions. Using a high-affinity anti-BLR1 monoclonal antibody (MoAb) and three-color flow cytometry it is shown that BLR1 expression on peripheral blood cells is limited to B cells and to a subset of CD4+ (14%) and CD8+ (2%) lymphocytes. T cells expressing BLR1 were positive for CD45R0, were negative for interleukin-2 receptors, show high levels of CD44, and show low levels of L-selectin. The majority of CD4+ cells originating from secondary lymphatic tissue, but none of cord blood- derived T cells, express BLR1. These observations suggest that BLR1 is a marker for memory T cells. Furthermore, BLR1 expression was detected on all CD19+ peripheral or tonsillar B lymphocytes, but only on a fraction of cord blood cells and bone marrow cells expressing CD19, sIgM, or sIgD. Interestingly, activation of both mature B and T cells by CD40 MoAb and CD3 MoAb, respectively, led to complete downregulation of BLR1. These data suggest that the G-protein-coupled receptor BLR1 is involved in functional control of mature recirculating B cells and T- helper memory cells participating in cell migration and cell activation.

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Maturation of Lymphocyte Immunophenotypes and Memory T Helper Cell Differentiation During Development in Mice

Developmental Immunology ◽

10.1155/2000/56106 ◽

2000 ◽

Vol 8 (1) ◽

pp. 47-60 ◽

Cited By ~ 5

Author(s):

Omar R. Fagoaga ◽

Steven. M. Yellon ◽

Sandra. L. Nehlsen-Cannarella

Keyword(s):

Immune Response ◽

T Cells ◽

Cell Differentiation ◽

B Cells ◽

Cell Subset ◽

T Helper Cell ◽

Natural Killers ◽

Memory Cells ◽

Spleen Lymphocyte ◽

T Helper

The goal of this study was to systematically investigate the ontogeny of lymphoid populations throughout postnatal development. In CD-1 mice, peak lymphocyte numbers occurred in blood on postnatal day 10 (dl0) including those for natural killers (NK1.1), B cells (CD19), T helper (CD3CD4), naïve T helper (CD4CD62LposCD44low), memory T helper (CD4CD62LnegCD44high), and T cytotoxic (CD3CD8) cells. As percent of total lymphocytes, peaks were achieved by d10 for all T helper subtypes but not B cells which declined to a nadir. In spleen, lymphocyte numbers increased exponentially after d10. Proportionately, NK and T cells peaked on d10, declined by d20, and increased 2–3-fold by d45. Naive T cells constituted the majority of lymphocytes during development while memory cells gained to 2.2% (blood) and 12 % (spleen) by d20. C57BL/6 mice had similar profiles except that the B cell nadir and T cell subset peaks were at d5. Peripheralization of critical numbers of lymphocytes by d10, and importantly, development of a repertoire of memory cells by d20, may define immune response capabilities that close the period of immaturity for the neonate.

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L-selectin deficiency decreases aortic B1a and Breg subsets and promotes atherosclerosis

Thrombosis and Haemostasis ◽

10.1160/th13-10-0865 ◽

2014 ◽

Vol 112 (10) ◽

pp. 803-811 ◽

Cited By ~ 22

Author(s):

Breanne Gjurich ◽

Parésa Taghavie-Moghadam ◽

Klaus Ley ◽

Elena Galkina

Keyword(s):

B Cells ◽

Neutrophil Migration ◽

Fold Increase ◽

Interleukin 10 ◽

Plaque Burden ◽

Chow Diet ◽

Blood Neutrophil ◽

Peripheral Tissues ◽

Cell Counts

SummaryThere is a significant recruitment of leucocytes into aortas during atherogenesis. L-selectin regulates leucocyte migration into secondary lymphoid and peripheral tissues and was proposed to play a role in leucocyte homing into aortas. Here, we determine the role of L-selectin in atherosclerosis. L-selectin-deficient Apoe -/- (Sell -/- Apoe -/-) mice had a 74% increase in plaque burden compared to Apoe -/- mice fed a chow diet for 50 weeks. Elevated atherosclerosis was accompanied by increased aortic leucocyte content, but a 50% reduction in aortic B cells despite elevated B cell counts in the blood. Follicular B cells represented 65%, whereas B1a and regulatory B cells (Breg) comprised 5% of aortic B cells. B1a and Breg cell subsets were reduced in Sell -/- Apoe -/- aortas with accompanied two-fold decrease in aortic T15 antibody and 1.2-fold decrease of interleukin-10 (IL-10) levels. L-selectin was required for B1 cell homing to the atherosclerotic aorta, as demonstrated by a 1.5-fold decrease in the migration of Sell -/- Apoe -/- vs Apoe -/- cells. Notably, we found a 1.6-fold increase in CD68hi macrophages in Sell -/- Apoe -/- compared to Apoe -/- aortas, despite comparable blood monocyte numbers and L-selectin-dependent aortic homing. L-selectin had no effect on neutrophil migration into aorta, but led to elevated blood neutrophil numbers, suggesting a potential involvement of neutrophils in atherogenesis of Sell -/- Apoe -/- mice. Thus, L-selectin deficiency increases peripheral blood neutrophil and lymphocyte numbers, decreases aortic B1a and Breg populations, T15 antibody and IL-10 levels, and increases aortic macrophage content of Sell -/- Apoe -/- mice. Altogether, these data provide evidence for an overall atheroprotective role of L-selectin.

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Index of Bone Marrow Output and Imbalance of B-Lymphocyte Homeostasis before and after Transplantation Correlate Differently with Graft-Versus-Host Disease and Relapse

Blood ◽

10.1182/blood.v126.23.3150.3150 ◽

2015 ◽

Vol 126 (23) ◽

pp. 3150-3150

Author(s):

Crisitina Skert ◽

Simone Perucca ◽

Imberti Luisa ◽

Chiarini Marco ◽

Michele Malagola ◽

...

Keyword(s):

Bone Marrow ◽

T Cells ◽

B Cells ◽

Acute Gvhd ◽

Chronic Gvhd ◽

Effector Memory ◽

Memory Cells ◽

Immunological Parameters ◽

Immature B Cells ◽

Effector Memory Cells

Abstract Introduction The long-term efficacy of allogeneic haematopoietic stem cell transplantation (SCT) relies primarily on the Graft-versus-tumor (GVT) effect, which partially overlaps with Graft versus Host disease (GvHD), the most common cause of morbidity and mortality in SCT. Researches on GVHD-biomarkers are still ongoing and a set of validate markers are still lacking, especially for chronic GVHD. Furthermore, immune parameters that univocally associate with GVHD or GVT have not been identified yet. In this study, lymphocyte subsets together with TCR-repertoire analysis, and index of thymic and bone marrow output were evaluated at different time points, in order to identify possible predictors of GVHD and ineffective GVT. Methods Prospective evaluations of lymphocyte subsets, thymic and bone marrow output were performed in 40 patients before SCT, at 30, 90, 180 days and 1 year after SCT. CD4+/CD8+ naïve, central memory, effector memory, terminally differentiated effector memory (TEMRA) cells, subsets of regulatory T-lymphocytes, immature B cells, naïve, switched and unswitched memory B cells, memory double negative (IgD-CD27-) B cells were analysed by flow cytometry. Analysis of thymic and bone marrow output was performed by detection of T cell receptor excision circles (TRECs) and kappa-deleting recombination circles (KRECs). TRECs and KRECs were simultaneously quantified by a duplex quantitative Real-Time PCR. Heteroduplex assay was used to perform TCR-repertoire analysis. A 2-step multivariate analysis was performed using principal component analysis (PCA) and Cox regression analysis, to solve the problem of the high number of variables (immunological, patients- and transplant related) in comparison with the relatively limited and heterogeneous pool of patients. Results Twenty patients developed acute GVHD (median time: 28 days, range 19-120). Chronic GVHD was observed in 9 patients (median time: 6 months, range 4-10). In multivariate analysis, acute GVHD correlated positively with pre-transplant percentage of CD4+ central memory cells, and with values of regulatory effector memory T-cells and CD4+TEMRA cell at day +30 (p=0,0006). Pre-transplant percentage of unswitched memory B cells was also associated with acute GVHD, whereas pre-transplant levels of KRECs were inversely correlated (p=0,0005). Chronic GVHD was associated with matched unrelated donor and with (p<0,05): -values of regulatory effector memory T-cells at +30, percentage of CD8+TEMRA cells at +90, values of immature B cells and levels of KRECs at +180 (positive correlation) -percentage of CD4+ central memory and CD8+ effector memory cells at +90 (negative correlation). The relapse rate (27%; median time: 5,5 months, range 3-12) was used as clinical index of ineffective GVT. The following cluster of immunological parameters at day +90 correlated positively with relapse: CD8+ effector memory cells, immature B cells, naïve, switched memory B cells, memory double negative (IgD-CD27-) B cells (p=0,006). Discussion Different clusters of immunological parameters at different time points were evidenced as predictors of GVHD and ineffective GVT, allowing a clear-cut distinction between these immunological reactions. Changes in pre- and post-transplant B-lymphopoietic microenvironment and specific imbalances in the subset of B-cells may be involved in acute and chronic GVHD development. The atypical association of regulatory T-cells with GVHD may be explained by the relative efficiency of different subsets of regulatory T-cells (naïve>effector memory), as shown in some experimental models. Increased values of CD8+ effector memory cells could be an early sign of ineffective GVL. Imbalance toward a lymphocyte B-response, and especially toward "senescent" memory (IgD-CD27-) B cells, could promote tolerance to tumor cells. The validation of these clusters of immunological parameters as specific early predictors of GVHD or GVT, even before SCT, could potentially allow the development of pre-emptive and targeted therapies. Disclosures No relevant conflicts of interest to declare.

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Induction of CD4+CD8+double positive T cells and increase in CD5+B cells in efferent lymph in sheep infected withTrypanosoma evansi

Parasite Immunology ◽

10.1111/j.1365-3024.1998.00125.x ◽

1998 ◽

Vol 20 (3) ◽

pp. 121-134 ◽

Cited By ~ 8

Author(s):

DENIS N. ONAH ◽

JOHN HOPKINS ◽

ANTONY G. LUCKINS

Keyword(s):

T Cells ◽

B Cells ◽

Double Positive

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Fc receptor-like 4 and 5 define human atypical memory B cells

International Immunology ◽

10.1093/intimm/dxaa053 ◽

2020 ◽

Vol 32 (12) ◽

pp. 755-770

Author(s):

Huifang Li ◽

Jessica Dement-Brown ◽

Pei-Jyun Liao ◽

Ilya Mazo ◽

Frederick Mills ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Human Memory ◽

Memory B Cells ◽

Surface Proteins ◽

Quiescent State ◽

Memory Cells ◽

Lineage Trees ◽

Memory Subset

Abstract Atypical memory B cells accumulate in chronic infections and autoimmune conditions, and commonly express FCRL4 and FCRL5, respective IgA and IgG receptors. We characterized memory cells from tonsils on the basis of both FCRL4 and FCRL5 expression, defining three subsets with distinct surface proteins and gene expression. Atypical FCRL4+FCRL5+ memory cells had the most discrete surface protein expression and were enriched in cell adhesion pathways, consistent with functioning as tissue-resident cells. Atypical FCRL4−FCRL5+ memory cells expressed transcription factors and immunoglobulin genes that suggest poised differentiation into plasma cells. Accordingly, the FCRL4−FCRL5+ memory subset was enriched in pathways responding to endoplasmic reticulum stress and IFN-γ. We reconstructed ongoing B-cell responses as lineage trees, providing crucial in vivo developmental context. Each memory subset typically maintained its lineage, denoting mechanisms enforcing their phenotypes. Classical FCRL4−FCRL5− memory cells were infrequently detected in lineage trees, suggesting the majority were in a quiescent state. FCRL4−FCRL5+ cells were the most represented memory subset in lineage trees, indicating robust participation in ongoing responses. Together, these differences suggest FCRL4 and FCRL5 are unlikely to be passive markers but rather active drivers of human memory B-cell development and function.

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Incidence of Centrosome Amplification in Multiple Myeloma.

Blood ◽

10.1182/blood.v114.22.2827.2827 ◽

2009 ◽

Vol 114 (22) ◽

pp. 2827-2827

Author(s):

Jana Smejkalova ◽

Elena Dementyeva ◽

Pavel Nμmec ◽

Kryukov Fedor ◽

Karthick Raja Muthu Raja ◽

...

Keyword(s):

Multiple Myeloma ◽

B Cells ◽

Chromosomal Abnormalities ◽

Conflicts Of Interest ◽

Centrosome Amplification ◽

Population Characteristics ◽

Double Positive ◽

Healthy Donors ◽

Significant Difference ◽

Immunofluorescence Labeling

Abstract Abstract 2827 Poster Board II-803 Centrosome amplification (CA) has been previously detected in hematological malignancies including multiple myeloma (MM) and is usually associated with disease progression. CA leads to the formation of multipolar mitotic spindles that may lead to chromosome segregation errors and genomic instability. In this pilot study, we have evaluated the occurrence of CA in two populations of B-lineage cells including B-lymphocytes and plasma cells (PCs) of MM patients. We have analyzed possible associations of CA with established prognostic factors including the most common chromosomal abnormalities in malignant PCs. Immunofluorescence labeling was used for the evaluation of centrosome amplification (CA) in B-cells (CD19+) and PCs (CD138+) of MM patients. The centrin (centrosome protein) copy numbers were used to define three cellular subpopulations: (1) no centrin signal (Non-CS), (2) 1-4 centrin signals (1-4CS) or (3) more than 4 signals of centrin (CA). Samples with ≥11% of B-cells or ≥10% of PCs with >4 fluorescence signals of centrin were considered CA positive. A total of 70 patients were evaluated for CA in PCs and/or B-cells, including 18 patients who had analysis of both cell types. The patient population characteristics were as follows: males/females 34/36, median age of 65 years (range, 40-84 years). Most patients had advanced stage of MM (DS II/III n = 48; ISS II/III; n = 21). Peripheral blood samples from 20 healthy donors were used as controls and for the estimation of CA positivity threshold for B-cells (Mean + 3SD). There was a statistically significant difference between the percentage of B-cells subpopulations with centrosome amplification in MM patients and that in healthy donors ([Mean ± SD] 9.9 ± 7.9% versus 3.2 ± 2.5%; P<0.0001). The frequency of MM cases positive for CA was 34% (17/50) and 37% (14/38) based the analysis of PC samples and B-cell samples, respectively. Overall, 22% (4/18) MM patients were double-positive. No significant correlation was detected between B-cells and PCs (r=0.387; P=0.113) obtained from patients with both available samples. No significant associations were identified between CA status and the following common cytogenetic abnormalities in PCs: del(13)(q14) (p= 1.000); del(17)(p13) (p=0.132); gain(1)(q21) (p= 1.000), hyperdiploidy (p= 1.000). In summary, we have confirmed the presence of centrosome amplification in B-cells of MM patients. Immunofluorescence staining is a sensitive method for the detection of abnormal subpopulations of B-cells that probably represent a reservoir of clonogenic cells in MM. This study was supported by grants NR 8945-4/2006, MSM 0021622434, MZ LC 06027 and IGA NR 9317 from the Departments of Education and Health of the Czech Republic. Disclosures: No relevant conflicts of interest to declare.

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Patients Treated with Rituximab-Containing Immunochemotherapy Have a Significant and Prolonged Lack of Humoral Response to Influenza Vaccine Associated with a Persistent Depletion of B Memory Cells.

Blood ◽

10.1182/blood.v114.22.936.936 ◽

2009 ◽

Vol 114 (22) ◽

pp. 936-936

Author(s):

Davide Bedognetti ◽

Gabriele Zoppoli ◽

Carlotta Massucco ◽

Simonetta Zupo ◽

Mario Roberto Sertoli ◽

...

Keyword(s):

B Cells ◽

Complete Remission ◽

Influenza Vaccine ◽

Conflicts Of Interest ◽

Humoral Response ◽

Swine Flu ◽

Control Group ◽

Healthy Controls ◽

Memory Cells ◽

Long Time

Abstract Abstract 936 1 Background. Rituximab, anti-CD20 mAb, has become an essential drug for the treatment of Non Hodgkin Lymphoma (NHL). Although transient B cells depletion frequently occurs after Rituximab treatment, it usually resolves after 6-9 months. Nevertheless, high frequency of non-neutropenic infections and persistent hypogammaglobulinaemia during follow-up period have been recently reported. However, impaired humoral response to the recall and primary antigens was found in NHL patients during (or few months after), Rituximab treatment. Influenza vaccination is generally recommended in Lymphoma patients, but no data are available about the activity of this vaccine after Rituximab-based chemotherapy (RIT). 2 Objective. To assess humoral response to influenza vaccine after RIT in complete remission (CR) NHL pts, as compared to healthy subjects. 3 Patients and Methods. Considered that disease status might affect the immune response, only NHL pts without evidence of disease and that had completed RIT no less than 6 months before the accrual were eligible. Healthy volunteers served as an age-matched control group. All the subjects were vaccinated with the same commercially available influenza vaccine (contained 2 A and 1 B viral strains). Hemagglutinin inhibition assays were performed before and 4 weeks after vaccination. The EMEA parametres for assessment of vaccines were determined. Seroconversion rate (SC), seroprotection rate (SP), and mean fold increase after Beyer correction/logarithmic transformation (BMFI) were evaluated to compare the two groups. Circulating lymphocytic subpopulations, NK and Dendritic cells, were assessed by immuno-cytofluorometry to evaluate the presence of potentially relevant phenotypic perturbations after vaccination and between the two groups. 4 Results. During 2008/09 epidemic season, 31 patients (PTS) and 34 healthy controls (CTR) were enrolled and analyzed. The median period after RIT administration was 29 months (range 7- 54). SC, SP and BMFI were lower in PTS group compared with CTR group (p <0.05 or less in 7/9 evaluated parameters). However, according with the EMEA criteria after age stratification, only the PTS weren't sufficiently protected. PTS that received Fludarabine-Rituximab regime had a high probability not to respond to any of the 3 vaccine strains and a lower SC as compared to PTS treated with the others regimes (p<0.05). Interestingly, while peripheral CD27- naïve B-cells were present, CD27+ memory B-cell populations were significantly depleted in the patients (p<0.0001) [Fig]. 5 Conclusions. Patients treated with RIT, especially those treated with Rituximab-Fludarabine regimens, have a significant lack of humoral response to influenza vaccine compared with healthy controls, even long time after treatment administration. In these patients the vaccination does not appear to confer adequate protection. The profound depletion in CD27+ B memory cells observed in these patients may explain, in part, this humoral failure. These results raise the concern that PTS treated with RIT, even if in complete remission or on follow since a long time, may be at particular risk of infection, therefore needing careful surveillance, during this period of H1N1 swine-flu spreading. Disclosures: No relevant conflicts of interest to declare.

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