scholarly journals Monoclonal IgG antibodies generated from joint-derived B cells of RA patients have a strong bias toward citrullinated autoantigen recognition

2013 ◽  
Vol 210 (3) ◽  
pp. 445-455 ◽  
Author(s):  
Khaled Amara ◽  
Johanna Steen ◽  
Fiona Murray ◽  
Henner Morbach ◽  
Blanca M. Fernandez-Rodriguez ◽  
...  
Keyword(s):  
B Cells ◽  
Mhc Class Ii ◽  
Amino Acid Replacement ◽  
Igg Antibodies ◽  
Hla Dr ◽  
Citrullinated Proteins ◽  
T Cell Help ◽  
Active Antigen ◽  
Citrullinated Antigen ◽  
Selection Of

Antibodies targeting citrullinated proteins (ACPAs [anticitrullinated protein antibodies]) are commonly found in patients with rheumatoid arthritis (RA), strongly associate with distinct HLA-DR alleles, and predict a more aggressive disease course as compared with seronegative patients. Still, many features of these antibodies, including their site of production and the extent of MHC class II–driven T cell help, remain unclarified. To address these questions, we have used a single B cell–based cloning technology to isolate and express immunoglobulin (Ig) genes from joint-derived B cells of active RA patients. We found ∼25% of synovial IgG-expressing B cells to be specific for citrullinated autoantigens in the investigated ACPA+ RA patients, whereas such antibodies were not found in ACPA− patients. The citrulline-reactive monoclonal antibodies did not react with the unmodified arginine peptides, yet several reacted with more than one citrullinated antigen. A role for active antigen selection of the citrulline-reactive synovial B cells was supported by the strong bias toward amino acid replacement mutations in ACPA+ antibodies and by their loss of reactivity to citrullinated autoantigens when somatic mutations were reverted to the corresponding germline sequences.

The Function of Gingival Lymphocytes on the Establishment of Human Periodontitis

1988 ◽  
Vol 2 (2) ◽  
pp. 364-367 ◽  
Author(s):  
H. Okada ◽  
Y. Shimabukuro ◽  
Y. Kassai ◽  
H. Ito ◽  
T. Matsuo ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Mhc Class Ii ◽  
Plasma Cell ◽  
Cell Activity ◽  
Mouse Spleen ◽  
Autoreactive T Cells ◽  
Hla Dr ◽  
Igg Synthesis

Human periodontitis has been confirmed to be an IgG plasma cell-rich lesion. However, we also detected many T cells, both CD4-positive and CD8-positive cells, in periodontal lesions. Some of these T cells expressed HLA-DR (la-like) antigen on their surfaces, and the proportion of HLA-DR+ cells was approximately equal in both CD4+ and CD8+ cell populations (Okada et al., 1983, 1984). Consequently, both helper and suppressor T cells were believed to participate in the establishment of periodontal lesions. On the other hand, B cells were thought to be activated polyclonally in periodontal lesions, because a variety of periodontal florae possessed polyclonal B-cell-activating activity. We demonstrated that Actinomyces viscosus T14V stimulated mouse spleen B cells polyclonally and induced many IgM-producing cells but few IgG-producing cells. Moreover, IgG-producing cells were differentiated from only surface IgG-positive B cells but not from surface IgG-negative B cells-namely, surface IgM- or IgA-positive B cells (Harada et al., 1988). These results suggested that memory B cells, which had already been primed with appropriate antigens, might migrate into periodontal lesions, and then be activated polyclonally and develop into IgG-producing cells. The periodontal lesion could, therefore, be induced by the interactions of immunoregulatory mechanisms of T cells and polyclonal B cell activity of periodontal florae. In fact, L3T4-positive T cells (helper-inducer T cells) enhanced IgG synthesis of mouse spleen B cells which had been activated with T-independent B cell activators such as LPS and A. viscosus preparations (Okada et al., 1987; Ito et al., 1988). We hypothesized from the above results that autoreactive T cells recognized the increasing self-MHC class II(Ia) antigen on B cells which had been activated with polyclonal B cell activators, and then produced soluble factors, which could enhance IgG synthesis of these B cells. Autoreactive T cells as well as PBAs, thus, may play an important role in the establishment of the IgG plasma cell-rich periodontal lesion.

scholarly journals Two levels of help for B cell alloantibody production.

1996 ◽  
Vol 183 (2) ◽  
pp. 699-703 ◽  
Author(s):  
D J Steele ◽  
T M Laufer ◽  
S T Smiley ◽  
Y Ando ◽  
M J Grusby ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Mhc Class Ii ◽  
Class Ii ◽  
Igg Antibodies ◽  
Cd4 Cells ◽  
Mhc Class Ii Antigens ◽  
Cd4 Cell ◽  
Class Ii Antigens ◽  
Deficient Mice

We have examined whether T cell stimulation by direct or indirect pathways contributes to alloantibody production by B cells after major histocompatibility complex (MHC)-disparate skin graft rejection in mice. Experiments were performed using normal mice, MHC class II-deficient mice, MHC class II-deficient mice with an intact peripheral CD4+ cell population (due to expression of class II antigens only on thymic epithelium), mice lacking the cytoplasmic tail of their MHC class II antigens, and mice depleted of CD4+ cells by anti-CD4 monoclonal antibody treatment. Depletion of recipient CD4+ cells reduced alloantibody production to barely detectable levels. Absence of donor MHC class II antigens did not affect the production of either immunoglobulin (Ig)M or IgG antibodies directed at class I alloantigens. Absence of recipient MHC class II antigens, however, led to production of only IgM but not IgG antibodies, even if the recipients had an intact CD4+ cell population. Absence of the cytoplasmic tail of the recipient's MHC class II antigens led to the production of slightly reduced amounts of IgG antibody. These findings indicate that (a) CD4+ cells are essential helper cells for B cell alloantibody production; (b) production of IgM alloantibody can occur with help from CD4+ cells, which recognize either donor class II antigens or modified recipient class II antigens; (c) isotype switching from IgM to IgG alloantibody requires help from CD4+ cells activated by antigens presented by recipient MHC class II molecules; and (d) the cytoplasmic domain of the recipient MHC class II molecules may be involved in the mechanism that leads to isotype switching by B cells. Thus, there are two levels of CD4-mediated help available for B cells responding to alloantigens: one (involving a noncognate interaction) can produce B cell activation, and a second (involving a cognate interaction) is required for differentiation and IgG alloantibody production.

Multiple antibody reactivities to citrullinated antigens in sera from patients with rheumatoid arthritis: association with HLA-DRB1 alleles

2008 ◽  
Vol 68 (5) ◽  
pp. 736-743 ◽  
Author(s):  
O Snir ◽  
M Widhe ◽  
C von Spee ◽  
J Lindberg ◽  
L Padyukov ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Shared Epitope ◽  
Type Ii Collagen ◽  
Cross Reactivity ◽  
Igg Antibodies ◽  
Serum Samples ◽  
Hla Dr ◽  
Citrullinated Proteins ◽  
The Relationship ◽  
Citrullinated Protein

Background:Autoantibodies to cyclic citrullinated peptides (anti-CCP) are present in most patients with rheumatoid arthritis (RA), and associate with HLA-DRB1 shared epitope (SE) alleles.Objective:To investigate reactivities of anti-CCP to various citrullinated proteins/peptides, which represent potential autoantigens in RA, and to examine the relationship between such antibodies, and their association with genetic variants within HLA-DRB1 SE alleles.Methods:Serum samples from 291 patients with established RA and 100 sex- and age-matched healthy subjects were included in this study. Sera were first analysed for presence of anti-CCP antibodies and further for IgG and IgA antibodies towards candidate autoantigens in both their native and citrullinated form including: fibrinogen, α-enolase peptide-1 and the C1-epitope of type II collagen (C1III). Antibody specificity was confirmed by cross-reactivity tests. HLA-DR genotyping was performed.Results:72% of patients with RA were anti-CCP positive. Among the candidate autoantigens examined, IgG antibodies to citrullinated fibrinogen were found in 66% of patients’ sera and in 41% for both citrullinated α-enolase peptide-1 and citrullinated C1III. These antibodies were mainly seen in the anti-CCP-positive patient group; they were specific for their respective antigen and displayed limited cross reactivity. IgA responses were also detected, but less frequently than IgG. Anti-CCP and anti-citrullinated protein antibodies were associated with HLA-DRB1*04 rather than with HLA-DRB1*01 alleles.Conclusions:Antibodies directed against several citrullinated antigens are present in CCP-positive RA, with many patients displaying multireactivity. All specific reactivities were primarily associated with the HLA-DRB1*04 alleles, suggesting common pathways of anti-citrulline immunity.

scholarly journals A mechanism of T cell dependent selection of antigen engaged Germinal Center B cells

2016 ◽  
Author(s):  
Vinod Krishna ◽  
Kurtis E. Bachman
Keyword(s):  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Germinal Center ◽  
Peripheral Tolerance ◽  
B Cell Tolerance ◽  
Germinal Center Reaction ◽  
Dark Zone ◽  
T Cell Help ◽  
Selection Of

A model of B cell affinity selection is proposed, and an explanation of peripheral tolerance mechanisms through antibody repertoire editing is presented. We show that affinity discrimination between B cells is driven by a competition between obtaining T cell help and removal of B cells from the light zone, either through apoptosis or by a return to the dark zone of germinal centers. We demonstrate that this mechanism also allows for the negative selection of self reactive B cells and maintenance of B cell tolerance during the germinal center reaction. Finally, we demonstrate that clonal expansion upon return to the germinal center dark zone amplifies differences in the antigen affinity of B cells that survive the light zone.

scholarly journals Ubiquitin-mediated fluctuations in MHC class II facilitate efficient germinal center B cell responses

2016 ◽  
Vol 213 (6) ◽  
pp. 993-1009 ◽  
Author(s):  
Oliver Bannard ◽  
Simon J. McGowan ◽  
Jonatan Ersching ◽  
Satoshi Ishido ◽  
Gabriel D. Victora ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Mhc Class Ii ◽  
Somatic Hypermutation ◽  
Ectopic Expression ◽  
Cell Receptor ◽  
Class Ii ◽  
Affinity Maturation ◽  
Efficiency Of Selection ◽  
T Cell Help

Antibody affinity maturation occurs in germinal centers (GCs) through iterative rounds of somatic hypermutation and selection. Selection involves B cells competing for T cell help based on the amount of antigen they capture and present on their MHC class II (MHCII) proteins. How GC B cells are able to rapidly and repeatedly transition between mutating their B cell receptor genes and then being selected shortly after is not known. We report that MHCII surface levels and degradation are dynamically regulated in GC B cells. Through ectopic expression of a photoconvertible MHCII-mKikGR chimeric gene, we found that individual GC B cells differed in the rates of MHCII protein turnover. Fluctuations in surface MHCII levels were dependent on ubiquitination and the E3 ligase March1. Increases in March1 expression in centroblasts correlated with decreases in surface MHCII levels, whereas CD83 expression in centrocytes helped to stabilize MHCII at that stage. Defects in MHCII ubiquitination caused GC B cells to accumulate greater amounts of a specific peptide–MHCII (pMHCII), suggesting that MHCII turnover facilitates the replacement of old complexes. We propose that pMHCII complexes are periodically targeted for degradation in centroblasts to favor the presentation of recently acquired antigens, thereby promoting the fidelity and efficiency of selection.

scholarly journals Molecular characterization of major histocompatibility complex class II gene expression and demonstration of antigen-specific T cell response indicate a new phenotype in class II-deficient patients.

1995 ◽  
Vol 181 (4) ◽  
pp. 1411-1423 ◽  
Author(s):  
I Hauber ◽  
H Gulle ◽  
H M Wolf ◽  
M Maris ◽  
H Eggenbauer ◽  
...  
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
Major Histocompatibility Complex ◽  
B Cells ◽  
Mhc Class Ii ◽  
Class Ii ◽  
Specific Protein ◽  
Histocompatibility Complex ◽  
Hla Dr ◽  
Class Ii Antigens

Major histocompatibility complex (MHC) class II deficiency is an inherited autosomal recessive combined immunodeficiency. The disease is known as bare lymphocyte syndrome (BLS). BLS is characterized by a lack of constitutive MHC class II expression on macrophages and B cells as well as a lack of induced MHC class II expression on cells other than professional antigen-presenting cells (APCs) due to the absence of mRNA and protein of the human leukocyte antigen (HLA) class II molecules, designated HLA-DR, -DQ, and -DP. The defect in gene expression is located at the transcriptional level and affects all class II genes simultaneously. Here we have analyzed transcription and protein expression of class II antigens in Epstein-Barr virus (EBV)-transformed B lymphoblastoid cell lines and mononuclear cells (MNCs) of twin brothers. Whereas flow cytometric analysis failed to detect class II antigens on the cell surface of the patients' EBV-B cells and MNCs, examination of the genes coding for HLA-DR, -DQ, -DP, and the invariant chain (Ii) by reverse transcriptase-polymerase chain reaction amplification resulted in an unusual mRNA pattern in the B cell lines of the patients (HLA-DR alpha +, -DR beta, -DQ alpha +, -DQ beta -, -DP alpha -; -DP beta +, Ii+). In accordance with these findings no HLA-DR beta-specific protein was detected by immunoblotting, whereas low levels of HLA-DR alpha and normal levels of Ii were present. In contrast to EBV-B cells, the MNCs of both patients displayed a residual HLA-DR beta, -DQ beta, and -DP alpha mRNA signal. Furthermore, HLA-DR beta-specific protein was found in addition to HLA-DR alpha by immunoblotting of cell lysates, even though it was clearly decreased as compared with controls. Our results indicate that the defect in class II antigen expression is not necessarily present to the same extent in B cells and cells of other lineages. mRNA levels of HLA-DR beta were found to be enriched in adherent cells within the MNC fraction. Further investigations indicated that the MHC class II expressed is functional in antigen presentation, as the two boys' CD4+ T cells became activated and expressed interleukin-2R after stimulation of peripheral blood mononuclear cell cultures with recall antigen (tetanus toxoid). Furthermore, T cells tested in one of the two patients responded to both MHC class I and II allostimulation, and this response was inhibited by monoclonal antibodies of the respective specificity.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Increased Activated Circulating T Follicular Helper Cells and Changes in B Cell Subsets in Immune TTP (iTTP) and in Response to Rituximab Treatment

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 23-24
Author(s):  
Jin-Sup Shin ◽  
Geraldine Cambridge ◽  
Yanping Guo ◽  
Marie Scully ◽  
Mari Thomas
Keyword(s):  
B Cells ◽  
B Cell ◽  
Advisory Board ◽  
Memory B Cells ◽  
Adamts13 Activity ◽  
Igg Antibodies ◽  
Follicular Helper ◽  
B Cell Subsets ◽  
T Cell Help

Background: T follicular helper cells (Tfh), characterised by surface expression of CXCR5, PD1 and ICOS, regulate development of antigen-specific B cell immunity through germinal centre (GC) formation, generation of long-lived memory B cells and high-affinity plasma cells. Methods: In this prospective study of peripheral blood B and circulating Tfh (cTfh) cell subsets, iTTP patients at 32 acute presentations, 23 elective rituximab (ER) episodes and 27 age & sex-matched healthy controls (HC) were studied using flow cytometry. All acute cases received PEX, steroids and RTX. All ER patients previously received RTX as acute therapy or previous ER at a median of 22 months (range 12-191 months). Serial samples were taken post-rituximab (RTX). B cell return was defined by laboratory CD19 count (<5 x 106/L). Statistical analysis was performed using GraphPad Prism 8. Results: 11/32 (34%) acute cases received potentially immunomodulatory therapy prior to blood sampling and were excluded. Median ADAMTS13 activity was <5 IU/dL (<5-10.4 IU/dL) and anti-ADAMTS13 IgG 46% (2-127%). In 23 ER cases, median ADAMTS13 activity was 9 IU/dL (<5-24IU/dL) and antibody 8% (2-89%). At acute presentation, CD4+CXCR5+ and CD4+CXCR5+PD1+ cTfh were decreased compared to HC (6.1% vs 9.4%; [p=0.003] and 1.2% vs 1.8%; [p=0.003] respectively), whereas activated cTfh (CD4+CXCR5+PD1+ICOS+) were increased (0.95% vs 0.55%; [p=0.01]) (Table 1). B cell subsets in acute iTTP showed decreased pre-switch and switched memory subsets compared to HC: IgD+/CD27+ [p=0.003]; IgD-/CD27+ [p=0.02] and IgD-/CD38+ [p=0.008]. Plasmablasts (IgD-CD38++) were increased [p=0.03] (Figure 1). ER patients pre-RTX had increased transitional and naïve B cells compared to HC [p=0.001; p<0.0001 respectively] and increased percentages of plasmablasts [p<0.0001]. Memory subsets defined by IgD/CD38 were all significantly decreased [p<0.0001] (Figure 1). Activated cTfh were increased in ER pre-RTX compared to HC [p<0.0001], whereas CD4+CXCR5+ICOS+ cells were reduced. There was no difference in CD4+CXCR5+ cells (Table 1). Memory subsets (defined by IgD/CD38) in ER were all significantly reduced compared with acute iTTP cases (Figure 1) likely to be due to previously described (often long term) changes in B cell subsets following B cell return after RTX. Longitudinal analysis: B cell return post-RTX in acute cases occurred mainly with transitional/naïve cells at a median of 8 months (0.5-14) but was not associated with iTTP relapse. Memory B cell subsets (defined by IgD/CD38) were significantly reduced at B cell return (Table 2). In ER patients, B cell subsets at repopulation were generally similar to levels seen prior to re-treatment with RTX. Frequency of cTfh was not significantly altered by RTX therapy in either acute TTP or ER. Two ER patients were followed longitudinally from RTX therapy, through ADAMTS13 normalisation & subsequent fall requiring further RTX re-treatment. Asymptomatic ADAMTS13 relapse (activity <15 IU/dL) was temporally related with an apparent maturation to memory phenotype and increase in % plasmablasts. Conclusions: At acute iTTP presentation and prior to elective re-treatment with RTX, activated (CD4+CXCR5+PD1+ICOS+) cTfh cells are increased, suggesting a role of T cell help in development of anti-ADAMTS13 IgG antibodies. Prior to RTX, B cell phenotype is also altered in acute TTP, with decreased frequency of memory subsets and a trend to increased naïve cells and plasmablasts. Persistent changes in B cell subsets were seen in ER patients who had received previous RTX with naive cells predominating and reduced memory cells. Interestingly, no patient relapsed/ required re-treatment related to B cell return, with relapse occurring at least 4 months after detection of B cells. Resumption of the autoimmune response therefore appeared limited by the rate of maturation of autoantigen(ADAMTS13)-specific B cells, either by selection/differentiation of ADAMTS13-naive B cells and/or expansion of ADAMTS13-specific memory B cells to Ig producing cells. This process, presumably driven by interaction with Tfh cells, suggests a role of T cell help in development of anti-ADAMTS13 IgG antibodies. Longitudinal analysis of the evolution of B and cTfh cells may help in predicting relapse in iTTP. Disclosures Scully: Alexion: Consultancy, Speakers Bureau; Ablynx/Sanofi: Consultancy, Other: Advisory Board, Speakers Bureau; Novartis: Other: Advisory Board, Speakers Bureau; Takeda: Consultancy, Speakers Bureau; Sanofi: Consultancy, Speakers Bureau; Takeda: Speakers Bureau; Shire/Takeda: Other: Advisory Board, Research Funding, Speakers Bureau. Thomas:Ablynx: Honoraria, Other: Advisory Board; Sanofi: Honoraria, Other: Advisory Board; Bayer: Honoraria, Speakers Bureau.

scholarly journals Detecting specific memory t and b cells in volunteers annually revaccinated with live anthrax vaccine

2019 ◽  
Vol 9 (3-4) ◽  
pp. 495-503
Author(s):  
V. V. Firstova ◽  
A. S. Kartseva ◽  
M. V. Silkina ◽  
M. A. Marin ◽  
Ia. O. Muntian ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Peripheral Blood ◽  
Early Stage ◽  
T Cell Subsets ◽  
Cytotoxic T Cell ◽  
Igg Antibodies ◽  
Specific Memory ◽  
Hla Dr

Currently, live anthrax vaccine has been used for vaccine prophylaxis in Russia and neighbor countries for seve ral decades, but precise mechanism of post-vaccination protection mechanism remains unclear. Here, we provide data on examining serum antibody level against protective antigen (PA) and lethal factor (LF) in repeatedly vaccinated volun teers at early stage (5–8 days) and 1 month after the performing pre-scheduled annual revaccination. Amount of peripheral blood antigen-specific memory T cells after previous vaccinations was analyzed. It was showed that frequency of CD3+CD45RO+CD62L– memory effector T cells was increased in the majority of volunteers on day 5-8 day after performing pre-scheduled annual revaccination that peaked at day 7 by elevating it by 2-fold compared with the control group. Percentage of anthrax-specific central memory T cells did not increase at early stage after vaccination, whereas amount of activated CD3+CD45RO+CD62L+HLA-DR+ subset within this memory T cell population was increased. Likewise, percentage of activated CD3+CD45RO+CD62L–HLA-DR+ effector memory T cell subset was also increased. Moreover, serum anti-PA IgG were detected on day 5–8 day after pre-scheduled annual revaccination in half of volunteers, whereas anti-LF IgG were found only in a single volunteer. Rapidly elevated amount of serum anthrax-specific IgG antibodies evidences about sustained memory B cell response in peripheral blood samples in volunteers after pre-scheduled annual revaccination. However, percentage of CD19+CD27+ memory B cells was not significantly elevated at early stage after revaccination that tended to increase. Both helper and cytotoxic T cell subsets were activated on day 5–8 after revaccination revealed by upregulated expression of CD69 and/or CD25 markers, with the latter predominantly found on helper T cells, thereby accounting for their high proliferative activity, whereas the former — on cytotoxic T cell subsets. Detection of anti-PA IgG antibodies correlates with protection against anthrax, which was confirmed in animal models. Unfortunately, the level of serum anti-PA IgG antibodies rapidly declines after vaccination. Ability of memory B cells to rapidly trigger production of anthrax-specific antibodies in response to revaccination suggests that anti-anthrax immunity may be evaluated by measuring frequency of peripheral blood anthrax-specific memory B and T cells.

Mice with MHC class II− B cells

1997 ◽  
Vol 56 (1-3) ◽  
pp. 203 ◽  
Author(s):  
G Williams
Keyword(s):  
B Cells ◽  
Mhc Class Ii ◽  
Class Ii
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