Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 109
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Exp Med ; 218(2)2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33119033

RESUMO

The TNF superfamily ligand BAFF maintains the survival of naive B cells by signaling through its surface receptor, BAFFR. Activated B cells maintain expression of BAFFR after they differentiate into germinal center (GC) or memory B cells (MBCs). However, the functions of BAFFR in these antigen-experienced B cell populations remain unclear. Here, we show that B cell-intrinsic BAFFR does not play a significant role in the survival or function of GC B cells or in the generation of the somatically mutated MBCs derived from them. Instead, BAFF/BAFFR signaling was required to generate the unmutated, GC-independent MBCs that differentiate directly from activated B cell blasts early in the response. Furthermore, amplification of BAFFR signaling in responding B cells did not affect GCs or the generation of GC-derived MBCs but greatly expanded the GC-independent MBC response. Although BAFF/BAFFR signaling specifically controlled the formation of the GC-independent MBC response, both types of MBCs required input from this pathway for optimal long-term survival.

2.
Proc Natl Acad Sci U S A ; 117(36): 22341-22350, 2020 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-32855302

RESUMO

Conformational diversity and self-cross-reactivity of antigens have been correlated with evasion from neutralizing antibody responses. We utilized single cell B cell sequencing, biolayer interferometry and X-ray crystallography to trace mutation selection pathways where the antibody response must resolve cross-reactivity between foreign and self-proteins bearing near-identical contact surfaces, but differing in conformational flexibility. Recurring antibody mutation trajectories mediate long-range rearrangements of framework (FW) and complementarity determining regions (CDRs) that increase binding site conformational diversity. These antibody mutations decrease affinity for self-antigen 19-fold and increase foreign affinity 67-fold, to yield a more than 1,250-fold increase in binding discrimination. These results demonstrate how conformational diversity in antigen and antibody does not act as a barrier, as previously suggested, but rather facilitates high affinity and high discrimination between foreign and self.


Assuntos
Anticorpos , Diversidade de Anticorpos/genética , Autoantígenos , Rearranjo Gênico do Linfócito B/genética , Mutação/genética , Animais , Anticorpos/química , Anticorpos/genética , Anticorpos/metabolismo , Afinidade de Anticorpos/genética , Autoanticorpos/química , Autoanticorpos/genética , Autoanticorpos/metabolismo , Autoantígenos/química , Autoantígenos/metabolismo , Regiões Determinantes de Complementaridade/genética , Imunidade Humoral/genética , Camundongos , Modelos Moleculares , Conformação Proteica , Hipermutação Somática de Imunoglobulina/genética
3.
Mol Metab ; 41: 101048, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32610071

RESUMO

OBJECTIVE: Glycogen is a major energy reserve in liver and skeletal muscle. The master metabolic regulator AMP-activated protein kinase (AMPK) associates with glycogen via its regulatory ß subunit carbohydrate-binding module (CBM). However, the physiological role of AMPK-glycogen binding in energy homeostasis has not been investigated in vivo. This study aimed to determine the physiological consequences of disrupting AMPK-glycogen interactions. METHODS: Glycogen binding was disrupted in mice via whole-body knock-in (KI) mutation of either the AMPK ß1 (W100A) or ß2 (W98A) isoform CBM. Systematic whole-body, tissue and molecular phenotyping was performed in KI and respective wild-type (WT) mice. RESULTS: While ß1 W100A KI did not affect whole-body metabolism or exercise capacity, ß2 W98A KI mice displayed increased adiposity and impairments in whole-body glucose handling and maximal exercise capacity relative to WT. These KI mutations resulted in reduced total AMPK protein and kinase activity in liver and skeletal muscle of ß1 W100A and ß2 W98A, respectively, versus WT mice. ß1 W100A mice also displayed loss of fasting-induced liver AMPK total and α-specific kinase activation relative to WT. Destabilisation of AMPK was associated with increased fat deposition in ß1 W100A liver and ß2 W98A skeletal muscle versus WT. CONCLUSIONS: These results demonstrate that glycogen binding plays critical roles in stabilising AMPK and maintaining cellular, tissue and whole-body energy homeostasis.

5.
J Exp Med ; 217(7)2020 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-32407433

RESUMO

Memory B cells (MBCs) are key for protection from reinfection. However, it is mechanistically unclear how germinal center (GC) B cells differentiate into MBCs. MYC is transiently induced in cells fated for GC expansion and plasma cell (PC) formation, so-called positively selected GC B cells. We found that these cells coexpressed MYC and MIZ1 (MYC-interacting zinc-finger protein 1 [ZBTB17]). MYC and MIZ1 are transcriptional activators; however, they form a transcriptional repressor complex that represses MIZ1 target genes. Mice lacking MYC-MIZ1 complexes displayed impaired cell cycle entry of positively selected GC B cells and reduced GC B cell expansion and PC formation. Notably, absence of MYC-MIZ1 complexes in positively selected GC B cells led to a gene expression profile alike that of MBCs and increased MBC differentiation. Thus, at the GC positive selection stage, MYC-MIZ1 complexes are required for effective GC expansion and PC formation and to restrict MBC differentiation. We propose that MYC and MIZ1 form a module that regulates GC B cell fate.

6.
Cell ; 180(5): 878-894.e19, 2020 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-32059783

RESUMO

Pathogenic autoantibodies arise in many autoimmune diseases, but it is not understood how the cells making them evade immune checkpoints. Here, single-cell multi-omics analysis demonstrates a shared mechanism with lymphoid malignancy in the formation of public rheumatoid factor autoantibodies responsible for mixed cryoglobulinemic vasculitis. By combining single-cell DNA and RNA sequencing with serum antibody peptide sequencing and antibody synthesis, rare circulating B lymphocytes making pathogenic autoantibodies were found to comprise clonal trees accumulating mutations. Lymphoma driver mutations in genes regulating B cell proliferation and V(D)J mutation (CARD11, TNFAIP3, CCND3, ID3, BTG2, and KLHL6) were present in rogue B cells producing the pathogenic autoantibody. Antibody V(D)J mutations conferred pathogenicity by causing the antigen-bound autoantibodies to undergo phase transition to insoluble aggregates at lower temperatures. These results reveal a pre-neoplastic stage in human lymphomagenesis and a cascade of somatic mutations leading to an iconic pathogenic autoantibody.


Assuntos
Autoanticorpos/genética , Doenças Autoimunes/genética , Linfócitos B/imunologia , Linfoma/genética , Animais , Autoanticorpos/imunologia , Doenças Autoimunes/imunologia , Doenças Autoimunes/patologia , Linfócitos B/patologia , Proteínas Adaptadoras de Sinalização CARD/genética , Proteínas de Transporte/genética , Evolução Clonal/genética , Evolução Clonal/imunologia , Ciclina D3/genética , Guanilato Ciclase/genética , Humanos , Proteínas Imediatamente Precoces/genética , Região Variável de Imunoglobulina/genética , Região Variável de Imunoglobulina/imunologia , Proteínas Inibidoras de Diferenciação/genética , Linfoma/imunologia , Linfoma/patologia , Camundongos , Mutação/genética , Mutação/imunologia , Proteínas de Neoplasias/genética , Análise de Sequência de DNA/métodos , Análise de Sequência de RNA/métodos , Análise de Célula Única/métodos , Proteína 3 Induzida por Fator de Necrose Tumoral alfa/genética , Proteínas Supressoras de Tumor/genética , Recombinação V(D)J/genética
7.
Immunol Cell Biol ; 98(6): 480-489, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32080878

RESUMO

Preventing self-reactive lymphocytes from participating in effector responses is fundamental to maintaining immunological self-tolerance and circumventing autoimmunity. A range of complementary mechanisms are known to act upon the primary B- and T-cell repertoires to this effect, eliminating or silencing lymphocytes expressing self-reactive antigen receptors generated through V(D)J recombination in early lymphoid precursors. In the case of B cells, secondary diversification of antigen receptor repertoire by somatic hypermutation (SHM) provides an additional challenge, especially because this occurs in germinal center (GC) B cells that are actively responding to antigen and primed for differentiation into antibody-producing plasma cells. While it is clear that self-tolerance mechanisms do act to prevent antibody production by self-reactive GC B cells, it is also apparent that most pathogenic autoantibodies carry somatic mutations and so have derived from a GC response. Recent advances in the analysis of autoantibody-producing cells associated with human autoimmune diseases together with insights gained from animal models have increased our understanding of the relationships between GCs, SHM and autoantibody production. Here we discuss these developments and focus in particular on how they have illuminated the genesis and pathogenesis of one archetypal autoantibody, rheumatoid factor.

8.
J Exp Med ; 217(2)2020 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-31841125

RESUMO

Antibody-mediated autoimmune diseases are a major health burden. However, our understanding of how self-reactive B cells escape self-tolerance checkpoints to secrete pathogenic autoantibodies remains incomplete. Here, we demonstrate that patients with monogenic immune dysregulation caused by gain-of-function mutations in PIK3CD, encoding the p110δ catalytic subunit of phosphoinositide 3-kinase (PI3K), have highly penetrant secretion of autoreactive IgM antibodies. In mice with the corresponding heterozygous Pik3cd activating mutation, self-reactive B cells exhibit a cell-autonomous subversion of their response to self-antigen: instead of becoming tolerized and repressed from secreting autoantibody, Pik3cd gain-of-function B cells are activated by self-antigen to form plasmablasts that secrete high titers of germline-encoded IgM autoantibody and hypermutating germinal center B cells. However, within the germinal center, peripheral tolerance was still enforced, and there was selection against B cells with high affinity for self-antigen. These data show that the strength of PI3K signaling is a key regulator of pregerminal center B cell self-tolerance and thus represents a druggable pathway to treat antibody-mediated autoimmunity.


Assuntos
Formação de Anticorpos/genética , Autoanticorpos/imunologia , Classe I de Fosfatidilinositol 3-Quinases/genética , Mutação com Ganho de Função , Tolerância Imunológica/imunologia , Plasmócitos/imunologia , Animais , Autoanticorpos/sangue , Autoantígenos/imunologia , Autoimunidade/genética , Classe I de Fosfatidilinositol 3-Quinases/sangue , Classe I de Fosfatidilinositol 3-Quinases/metabolismo , Feminino , Centro Germinativo/imunologia , Humanos , Imunoglobulina M/sangue , Imunoglobulina M/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Transdução de Sinais/genética
9.
Curr Opin Immunol ; 63: 29-34, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31835060

RESUMO

Germinal centers (GCs) are well known for their important role in shaping the secondary B cell repertoire to generate antibodies capable of binding with high-affinity and specificity to foreign antigens. Somatic hypermutation of the Ig variable region genes in GC B cells represents a highly efficient mechanism for generating new antibody variants with increased antigen affinity. To be effective, however, this process needs to be intimately linked with equally efficient processes that positively select high-affinity clones for perpetuation in the GC and, ultimately, for differentiation into plasma cell and memory B cell effector populations. Just as important is the need for mechanisms of negative selection that remove GC B cell clones with unwanted specificities, particularly those that have gained reactivity with self-components. Here, we discuss recent advances in our understanding of the various selective processes that occur within the GC and identify the major questions in this field that remain to be answered.

10.
Nat Immunol ; 20(10): 1299-1310, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31534238

RESUMO

Resisting and tolerating microbes are alternative strategies to survive infection, but little is known about the evolutionary mechanisms controlling this balance. Here genomic analyses of anatomically modern humans, extinct Denisovan hominins and mice revealed a TNFAIP3 allelic series with alterations in the encoded immune response inhibitor A20. Each TNFAIP3 allele encoded substitutions at non-catalytic residues of the ubiquitin protease OTU domain that diminished IκB kinase-dependent phosphorylation and activation of A20. Two TNFAIP3 alleles encoding A20 proteins with partial phosphorylation deficits seemed to be beneficial by increasing immunity without causing spontaneous inflammatory disease: A20 T108A;I207L, originating in Denisovans and introgressed in modern humans throughout Oceania, and A20 I325N, from an N-ethyl-N-nitrosourea (ENU)-mutagenized mouse strain. By contrast, a rare human TNFAIP3 allele encoding an A20 protein with 95% loss of phosphorylation, C243Y, caused spontaneous inflammatory disease in humans and mice. Analysis of the partial-phosphorylation A20 I325N allele in mice revealed diminished tolerance of bacterial lipopolysaccharide and poxvirus inoculation as tradeoffs for enhanced immunity.


Assuntos
Infecções por Poxviridae/imunologia , Poxviridae/fisiologia , Domínios Proteicos/genética , Proteína 3 Induzida por Fator de Necrose Tumoral alfa/genética , Alelos , Animais , Extinção Biológica , Humanos , Imunidade , Inflamação , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Mutação de Sentido Incorreto/genética , Fosforilação
12.
J Allergy Clin Immunol ; 144(1): 236-253, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30738173

RESUMO

BACKGROUND: Gain-of-function (GOF) mutations in PIK3CD cause a primary immunodeficiency characterized by recurrent respiratory tract infections, susceptibility to herpesvirus infections, and impaired antibody responses. Previous work revealed defects in CD8+ T and B cells that contribute to this clinical phenotype, but less is understood about the role of CD4+ T cells in disease pathogenesis. OBJECTIVE: We sought to dissect the effects of increased phosphoinositide 3-kinase (PI3K) signaling on CD4+ T-cell function. METHODS: We performed detailed ex vivo, in vivo, and in vitro phenotypic and functional analyses of patients' CD4+ T cells and a novel murine disease model caused by overactive PI3K signaling. RESULTS: PI3K overactivation caused substantial increases in numbers of memory and follicular helper T (TFH) cells and dramatic changes in cytokine production in both patients and mice. Furthermore, PIK3CD GOF human TFH cells had dysregulated phenotype and function characterized by increased programmed cell death protein 1, CXCR3, and IFN-γ expression, the phenotype of a TFH cell subset with impaired B-helper function. This was confirmed in vivo in which Pik3cd GOF CD4+ T cells also acquired an aberrant TFH phenotype and provided poor help to support germinal center reactions and humoral immune responses by antigen-specific wild-type B cells. The increase in numbers of both memory and TFH cells was largely CD4+ T-cell extrinsic, whereas changes in cytokine production and TFH cell function were cell intrinsic. CONCLUSION: Our studies reveal that CD4+ T cells with overactive PI3K have aberrant activation and differentiation, thereby providing mechanistic insight into dysfunctional antibody responses in patients with PIK3CD GOF mutations.


Assuntos
Linfócitos T CD4-Positivos , Diferenciação Celular , Fosfatidilinositol 3-Quinases/genética , Animais , Linfócitos T CD4-Positivos/metabolismo , Citocinas/metabolismo , Mutação com Ganho de Função , Humanos , Camundongos , Fenótipo
13.
Nat Commun ; 9(1): 3372, 2018 08 22.
Artigo em Inglês | MEDLINE | ID: mdl-30135429

RESUMO

Vaccine-induced immunity depends on the generation of memory B cells (MBC). However, where and how MBCs are reactivated to make neutralising antibodies remain unknown. Here we show that MBCs are prepositioned in a subcapsular niche in lymph nodes where, upon reactivation by antigen, they rapidly proliferate and differentiate into antibody-secreting plasma cells in the subcapsular proliferative foci (SPF). This novel structure is enriched for signals provided by T follicular helper cells and antigen-presenting subcapsular sinus macrophages. Compared with contemporaneous secondary germinal centres, SPF have distinct single-cell molecular signature, cell migration pattern and plasma cell output. Moreover, SPF are found both in human and mouse lymph nodes, suggesting that they are conserved throughout mammalian evolution. Our data thus reveal that SPF is a seat of immunological memory that may be exploited to rapidly mobilise secondary antibody responses and improve vaccine efficacy.


Assuntos
Linfócitos B/metabolismo , Linfonodos/metabolismo , Animais , Linfócitos B/imunologia , Linfócitos T CD4-Positivos/metabolismo , Movimento Celular/efeitos dos fármacos , Células Cultivadas , Citometria de Fluxo , Humanos , Linfonodos/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Modelos Teóricos , Pirazóis/farmacologia , Pirimidinas/farmacologia , Tamoxifeno/farmacologia
14.
J Exp Med ; 215(8): 2073-2095, 2018 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-30018075

RESUMO

Gain-of-function (GOF) mutations in PIK3CD, encoding the p110δ subunit of phosphatidylinositide 3-kinase (PI3K), cause a primary immunodeficiency. Affected individuals display impaired humoral immune responses following infection or immunization. To establish mechanisms underlying these immune defects, we studied a large cohort of patients with PIK3CD GOF mutations and established a novel mouse model using CRISPR/Cas9-mediated gene editing to introduce a common pathogenic mutation in Pik3cd In both species, hyperactive PI3K severely affected B cell development and differentiation in the bone marrow and the periphery. Furthermore, PI3K GOF B cells exhibited intrinsic defects in class-switch recombination (CSR) due to impaired induction of activation-induced cytidine deaminase (AID) and failure to acquire a plasmablast gene signature and phenotype. Importantly, defects in CSR, AID expression, and Ig secretion were restored by leniolisib, a specific p110δ inhibitor. Our findings reveal key roles for balanced PI3K signaling in B cell development and long-lived humoral immunity and memory and establish the validity of treating affected individuals with p110δ inhibitors.


Assuntos
Linfócitos B/citologia , Linfócitos B/imunologia , Classe I de Fosfatidilinositol 3-Quinases/genética , Mutação em Linhagem Germinativa/genética , Fosfatidilinositol 3-Quinases/genética , Animais , Afinidade de Anticorpos/imunologia , Células da Medula Óssea/citologia , Diferenciação Celular , Proliferação de Células , Criança , Mutação com Ganho de Função/genética , Humanos , Switching de Imunoglobulina , Imunoglobulinas/metabolismo , Interleucinas/farmacologia , Camundongos , Modelos Animais , Fenótipo , Fosfatidilinositol 3-Quinases/metabolismo , Plasmócitos/metabolismo , Transdução de Sinais
15.
Am J Physiol Endocrinol Metab ; 315(2): E286-E293, 2018 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-29664675

RESUMO

Glucose transporter 6 (GLUT6) is a member of the facilitative glucose transporter family. GLUT6 is upregulated in several cancers but is not widely expressed in normal tissues. Previous studies have shown that GLUT6 knockdown kills endometrial cancer cells that express elevated levels of the protein. However, whether GLUT6 represents a viable anticancer drug target is unclear because the role of GLUT6 in normal metabolic physiology is unknown. Herein we generated GLUT6 knockout mice to determine how loss of GLUT6 affected whole body glucose homeostasis and metabolic physiology. We found that the mouse GLUT6 ( Slc2a6) gene expression pattern was similar to humans with mRNA found primarily in brain and spleen. CRISPR-Cas9-mediated deletion of Slc2a6 did not alter mouse development, growth, or whole body glucose metabolism in male or female mice fed either a chow diet or Western diet. GLUT6 deletion did not impact glucose tolerance or blood glucose and insulin levels in male or female mice fed either diet. However, compared with wild-type littermate controls, GLUT6 null female mice had a relatively minor decrease in fat accumulation when fed Western diet and had a lower respiratory exchange ratio when fed chow diet. Collectively, these data show that GLUT6 is not a major regulator of whole body metabolic physiology; therefore, GLUT6 inhibition may have minimal adverse effects if targeted for cancer therapy.


Assuntos
Proteínas Facilitadoras de Transporte de Glucose/genética , Metabolismo/genética , Metabolismo/fisiologia , Adiposidade/genética , Animais , Glicemia/metabolismo , Peso Corporal/genética , Sistemas CRISPR-Cas , Dieta , Metabolismo Energético/genética , Feminino , Genótipo , Glucose/metabolismo , Teste de Tolerância a Glucose , Homeostase/genética , Insulina/sangue , Masculino , Camundongos , Camundongos Knockout
16.
Proc Natl Acad Sci U S A ; 115(19): 4921-4926, 2018 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-29669924

RESUMO

Activation-induced deaminase (AID) initiates hypermutation of Ig genes in activated B cells by converting C:G into U:G base pairs. G1-phase variants of uracil base excision repair (BER) and mismatch repair (MMR) then deploy translesion polymerases including REV1 and Pol η, which exacerbates mutation. dNTP paucity may contribute to hypermutation, because dNTP levels are reduced in G1 phase to inhibit viral replication. To derestrict G1-phase dNTP supply, we CRISPR-inactivated SAMHD1 (which degrades dNTPs) in germinal center B cells. Samhd1 inactivation increased B cell virus susceptibility, increased transition mutations at C:G base pairs, and substantially decreased transversion mutations at A:T and C:G base pairs in both strands. We conclude that SAMHD1's restriction of dNTP supply enhances AID's mutagenicity and that the evolution of Ig hypermutation included the repurposing of antiviral mechanisms based on dNTP starvation.


Assuntos
Linfócitos B/imunologia , Fase G1/imunologia , Ativação Linfocitária , Mutação , Proteína 1 com Domínio SAM e Domínio HD , Hipermutação Somática de Imunoglobulina/imunologia , Animais , Linfócitos B/citologia , Citidina Desaminase/imunologia , DNA Polimerase Dirigida por DNA , Fase G1/genética , Masculino , Camundongos , Camundongos Transgênicos , Nucleotidiltransferases/genética , Nucleotidiltransferases/imunologia , Proteína 1 com Domínio SAM e Domínio HD/genética , Proteína 1 com Domínio SAM e Domínio HD/imunologia
17.
Science ; 360(6385): 223-226, 2018 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-29650674

RESUMO

Antibodies have the specificity to differentiate foreign antigens that mimic self antigens, but it remains unclear how such specificity is acquired. In a mouse model, we generated B cells displaying an antibody that cross-reacts with two related protein antigens expressed on self versus foreign cells. B cell anergy was imposed by self antigen but reversed upon challenge with high-density foreign antigen, leading to germinal center recruitment and antibody gene hypermutation. Single-cell analysis detected rapid selection for mutations that decrease self affinity and slower selection for epistatic mutations that specifically increase foreign affinity. Crystal structures revealed that these mutations exploited subtle topological differences to achieve 5000-fold preferential binding to foreign over self epitopes. Resolution of antigenic mimicry drove the optimal affinity maturation trajectory, highlighting the value of retaining self-reactive clones as substrates for protective antibody responses.


Assuntos
Anticorpos/genética , Formação de Anticorpos/genética , Autoantígenos/imunologia , Centro Germinativo/imunologia , Mimetismo Molecular/genética , Tolerância a Antígenos Próprios , Animais , Anticorpos/química , Anticorpos/imunologia , Afinidade de Anticorpos/genética , Linfócitos B/imunologia , Anergia Clonal , Reações Cruzadas , Cristalografia por Raios X , Camundongos , Camundongos Mutantes , Mutação , Nucleoproteínas/genética , Nucleoproteínas/imunologia , Seleção Genética , Análise de Célula Única
18.
J Exp Med ; 215(3): 801-813, 2018 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-29386231

RESUMO

Activated B cells can initially differentiate into three functionally distinct fates-early plasmablasts (PBs), germinal center (GC) B cells, or early memory B cells-by mechanisms that remain poorly understood. Here, we identify atypical chemokine receptor 4 (ACKR4), a decoy receptor that binds and degrades CCR7 ligands CCL19/CCL21, as a regulator of early activated B cell differentiation. By restricting initial access to splenic interfollicular zones (IFZs), ACKR4 limits the early proliferation of activated B cells, reducing the numbers available for subsequent differentiation. Consequently, ACKR4 deficiency enhanced early PB and GC B cell responses in a CCL19/CCL21-dependent and B cell-intrinsic manner. Conversely, aberrant localization of ACKR4-deficient activated B cells to the IFZ was associated with their preferential commitment to the early PB linage. Our results reveal a regulatory mechanism of B cell trafficking via an atypical chemokine receptor that shapes activated B cell fate.


Assuntos
Linfócitos B/citologia , Linfócitos B/metabolismo , Linhagem da Célula , Receptores CCR/metabolismo , Animais , Antígenos/metabolismo , Proliferação de Células , Centro Germinativo/metabolismo , Camundongos Endogâmicos C57BL , Baço/citologia
19.
Immunol Cell Biol ; 96(2): 128-136, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29363187

RESUMO

The G protein-coupled receptor 65 (GPR65) gene has been genetically associated with several autoimmune diseases, including multiple sclerosis (MS). GPR65 is predominantly expressed in lymphoid organs and is activated by extracellular protons. In this study, we tested whether GPR65 plays a functional role in demyelinating autoimmune disease. Using a murine model of MS, experimental autoimmune encephalomyelitis (EAE), we found that Gpr65-deficient mice develop exacerbated disease. CD4+ helper T cells are key drivers of EAE pathogenesis, however, Gpr65 deficiency in these cells did not contribute to the observed exacerbated disease. Instead, Gpr65 expression levels were found to be highest on invariant natural killer T (iNKT) cells. EAE severity in Gpr65-deficient mice was normalized in the absence of iNKT cells (CD1d-deficient mice), suggesting that GPR65 signals in iNKT cells are important for suppressing autoimmune disease. These findings provide functional support for the genetic association of GPR65 with MS and demonstrate GPR65 signals suppress autoimmune activity in EAE.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Encefalomielite Autoimune Experimental/imunologia , Células T Matadoras Naturais/imunologia , Transferência Adotiva , Animais , Modelos Animais de Doenças , Progressão da Doença , Encefalomielite Autoimune Experimental/patologia , Camundongos Endogâmicos C57BL , Glicoproteína Mielina-Oligodendrócito/imunologia , Fragmentos de Peptídeos/imunologia , Receptores Acoplados a Proteínas-G/deficiência , Receptores Acoplados a Proteínas-G/metabolismo
20.
Annu Rev Immunol ; 36: 339-357, 2018 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-29356584

RESUMO

Maintenance of immunological self-tolerance requires lymphocytes carrying self-reactive antigen receptors to be selectively prevented from mounting destructive or inflammatory effector responses. Classically, self-tolerance is viewed in terms of the removal, editing, or silencing of B and T cells that have formed self-reactive antigen receptors during their early development. However, B cells activated by foreign antigen can enter germinal centers (GCs), where they further modify their antigen receptor by somatic hypermutation (SHM) of their immunoglobulin genes. The inevitable emergence of activated, self-reactive GC B cells presents a unique challenge to the maintenance of self-tolerance that must be rapidly countered to avoid autoantibody production. Here we discuss current knowledge of the mechanisms that enforce B cell self-tolerance, with particular focus on the control of self-reactive GC B cells. We also consider how self-reactive GC B cells can escape self-tolerance to initiate autoantibody production or instead be redeemed via SHM and used in productive antibody responses.


Assuntos
Autoimunidade , Linfócitos B/imunologia , Centro Germinativo/imunologia , Animais , Autoanticorpos/imunologia , Autoantígenos/imunologia , Linfócitos B/metabolismo , Centro Germinativo/metabolismo , Humanos , Tolerância Imunológica , Ativação Linfocitária/genética , Ativação Linfocitária/imunologia , Plasmócitos/imunologia , Plasmócitos/metabolismo , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA