RESUMO
Differentiation of Ag-specific B cells into class-switched, high-affinity, Ab-secreting cells provides protection against invading pathogens but is undesired when Abs target self-tissues in autoimmunity, beneficial non-self-blood transfusion products, or therapeutic proteins. Essential T cell factors have been uncovered that regulate T cell-dependent B cell differentiation. We performed a screen using a secreted protein library to identify novel factors that promote this process and may be used to combat undesired Ab formation. We tested the differentiating capacity of 756 secreted proteins on human naive or memory B cell differentiation in a setting with suboptimal T cell help in vitro (suboptimal CD40L and IL-21). High-throughput flow cytometry screening and validation revealed that type I IFNs and soluble FAS ligand (sFASL) induce plasmablast differentiation in memory B cells. Furthermore, sFASL induces robust secretion of IgG1 and IgG4 Abs, indicative of functional plasma cell differentiation. Our data suggest a mechanistic connection between elevated sFASL levels and the induction of autoreactive Abs, providing a potential therapeutic target in autoimmunity. Indeed, the modulators identified in this secretome screen are associated with systemic lupus erythematosus and may also be relevant in other autoimmune diseases and allergy.
Assuntos
Células Produtoras de Anticorpos/imunologia , Diferenciação Celular/imunologia , Proteína Ligante Fas/imunologia , Memória Imunológica/imunologia , Interleucinas/imunologia , Lúpus Eritematoso Sistêmico/imunologia , Animais , Autoimunidade/imunologia , Linfócitos B/imunologia , Ligante de CD40/imunologia , Linhagem Celular , Células HEK293 , Humanos , Ativação Linfocitária/imunologia , Camundongos , Células NIH 3T3 , Plasmócitos/imunologia , Linfócitos T/imunologiaRESUMO
BACKGROUND: Trigeminal ganglia (TG) neurons are the main site of lifelong latent herpes simplex virus type 1 (HSV-1) infection. T-cells in ganglia contribute to long-term control of latent HSV-1 infection, but it is unclear whether these cells are bona fide tissue-resident memory T-cells (TRM). We optimized the processing of human post-mortem nervous tissue to accurately phenotype T-cells in human TG ex vivo and in situ. METHODS: Peripheral blood mononuclear cells (PBMC; 5 blood donors) were incubated with several commercial tissue digestion enzyme preparations to determine off-target effect on simultaneous detection of 15 specific T-cell subset markers by flow cytometry. Next, optimized enzymatic digestion was applied to ex vivo phenotype T-cells in paired PBMC, normal appearing white matter (NAWM) and TG of 8 deceased brain donors obtained < 9 h post-mortem by flow cytometry. Finally, the phenotypic and functional markers, and spatial orientation of T-cells in relation to neuronal somata, were determined in TG tissue sections of five HSV-1-latently infected individuals by multiparametric in situ analysis. RESULTS: Collagenase IV digestion of human nervous tissue was most optimal to obtain high numbers of viable T-cells without disrupting marker surface expression. Compared to blood, majority T-cells in paired NAWM and TG were effector memory T-cells expressing the canonical TRM markers CD69, CXCR6 and the immune checkpoint marker PD1, and about half co-expressed CD103. A trend of relatively higher TRM frequencies were detected in TG of latently HSV-1-infected compared to HSV-1 naïve individuals. Subsequent in situ analysis of latently HSV-1-infected TG showed the presence of cytotoxic T-cells (TIA-1+), which occasionally showed features of proliferation (KI-67+) and activation (CD137+), but without signs of degranulation (CD107a+) nor damage (TUNEL+) of TG cells. Whereas majority T-cells expressed PD-1, traits of T-cell senescence (p16INK4a+) were not detected. CONCLUSIONS: The human TG represents an immunocompetent environment in which both CD4 and CD8 TRM are established and retained. Based on our study insights, we advocate for TRM-targeted vaccine strategies to bolster local HSV-1-specific T-cell immunity, not only at the site of recurrent infection but also at the site of HSV-1 latency.
Assuntos
Herpes Simples , Infecções por Herpesviridae , Herpesvirus Humano 1 , Linfócitos T CD8-Positivos , Humanos , Antígeno Ki-67/metabolismo , Antígenos Comuns de Leucócito/metabolismo , Leucócitos Mononucleares , Células T de Memória , Receptor de Morte Celular Programada 1/metabolismo , Gânglio TrigeminalRESUMO
IgG4 antibodies are unique to humans. IgG4 is associated with tolerance during immunotherapy in allergy, but also with pathology, as in pemphigus vulgaris and IgG4-related disease. Its induction is largely restricted to nonmicrobial antigens, and requires repeated or prolonged antigenic stimulation, for reasons poorly understood. An important aspect in generating high-affinity IgG antibodies is chemokine receptor-mediated migration of B cells into appropriate niches, such as germinal centers. Here, we show that compared to IgG1 B cells, circulating IgG4 B cells express lower levels of CXCR3, CXCR4, CXCR5, CCR6, and CCR7, chemokine receptors involved in GC reactions and generation of long-lived plasma cells. This phenotype was recapitulated by in vitro priming of naive B cells with an IgG4-inducing combination of TFH /TH2 cytokines. Consistent with these observations, we found a low abundance of IgG4 B cells in secondary lymphoid tissues in vivo, and the IgG4 antibody response is substantially more short-lived compared to other IgG subclasses in patient groups undergoing CD20+ B cell depletion therapy with rituximab. These results prompt the hypothesis that factors needed to form IgG4 B cells restrain at the same time the induction of a robust migratory phenotype that could support a long-lived IgG4 antibody response.
Assuntos
Linfócitos B/imunologia , Imunoglobulina G/sangue , Receptores de Quimiocinas/fisiologia , Animais , Plasticidade Celular , Colite Ulcerativa/imunologia , Humanos , Imunoglobulina G/classificação , Interleucina-4/farmacologia , Camundongos , Células NIH 3T3RESUMO
OBJECTIVE: Results from anti-CD20 therapies demonstrate that B- and T-cell interaction is a major driver of multiple sclerosis (MS). The local presence of B-cell follicle-like structures and oligoclonal bands in MS patients indicates that certain B cells infiltrate the central nervous system (CNS) to mediate pathology. Which peripheral triggers underlie the development of CNS-infiltrating B cells is not fully understood. METHODS: Ex vivo flow cytometry was used to assess chemokine receptor profiles of B cells in blood, cerebrospinal fluid, meningeal, and brain tissues of MS patients (n = 10). Similar analyses were performed for distinct memory subsets in the blood of untreated and natalizumab-treated MS patients (n = 38). To assess T-bet(CXCR3)+ B-cell differentiation, we cultured B cells from MS patients (n = 21) and healthy individuals (n = 34) under T helper 1- and TLR9-inducing conditions. Their CNS transmigration capacity was confirmed using brain endothelial monolayers. RESULTS: CXC chemokine receptor 3 (CXCR3)-expressing B cells were enriched in different CNS compartments of MS patients. Treatment with the clinically effective drug natalizumab prevented the recruitment of CXCR3high IgG1+ subsets, corresponding to their increased ability to cross CNS barriers in vitro. Blocking of interferon-γ (IFNγ) reduced the transmigration potential and antigen-presenting function of these cells. IFNγ-induced B cells from MS patients showed increased T-bet expression and plasmablast development. Additional TLR9 triggering further upregulated T-bet and CXCR3, and was essential for IgG1 switching. INTERPRETATION: This study demonstrates that T-bethigh IgG1+ B cells are triggered by IFNγ and TLR9 signals, likely contributing to enhanced CXCR3-mediated recruitment and local reactivity in the CNS of MS patients. ANN NEUROL 2019;86:264-278.
Assuntos
Linfócitos B/metabolismo , Encéfalo/metabolismo , Esclerose Múltipla/metabolismo , Receptores CXCR3/biossíntese , Adulto , Idoso , Animais , Encéfalo/fisiologia , Movimento Celular/fisiologia , Feminino , Expressão Gênica , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade , Esclerose Múltipla/genética , Esclerose Múltipla/patologia , Células NIH 3T3 , Receptores CXCR3/genética , Adulto JovemRESUMO
CD70 and CD27 are costimulatory molecules that provide essential signals for the expansion and differentiation of CD8(+) T cells. Here, we show that CD27-driven costimulation lowered the threshold of T cell receptor activation on CD8(+) T cells and enabled responses against low-affinity antigens. Using influenza infection to study in vivo consequences, we found that CD27-driven costimulation promoted a CD8(+) T cell response of overall low affinity. These qualitative effects of CD27 on T cell responses were maintained into the memory phase. On a clonal level, CD27-driven costimulation established a higher degree of variety in memory CD8(+) T cells. The benefit became apparent when mice were reinfected, given that CD27 improved CD8(+) T cell responses against reinfection with viral variants, but not with identical virus. We propose that CD27-driven costimulation is a strategy to generate memory clones that have potential reactivity to a wide array of mutable pathogens.
Assuntos
Linfócitos T CD8-Positivos/metabolismo , Vírus da Influenza A/imunologia , Infecções por Orthomyxoviridae/imunologia , Especificidade do Receptor de Antígeno de Linfócitos T , Membro 7 da Superfamília de Receptores de Fatores de Necrose Tumoral/metabolismo , Animais , Variação Antigênica , Antígenos Virais/imunologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/patologia , Linfócitos T CD8-Positivos/virologia , Células Clonais , Humanos , Memória Imunológica , Vírus da Influenza A/patogenicidade , Ativação Linfocitária/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Especificidade do Receptor de Antígeno de Linfócitos T/genética , Membro 7 da Superfamília de Receptores de Fatores de Necrose Tumoral/genética , Membro 7 da Superfamília de Receptores de Fatores de Necrose Tumoral/imunologiaRESUMO
Apoptosis plays an essential role in the removal of activated CD8 T cells that are no longer required during or postinfection. The Bim-dependent intrinsic pathway of apoptosis removes effector CD8 T cells upon clearance of viral infection, which is driven by withdrawal of growth factors. Binding of Fas ligand to Fas mediates activation-induced T cell death in vitro and cooperates with Bim to eliminate CD8 T cells during chronic infection in vivo, but it is less clear how this pathway of apoptosis is initiated. In this study, we show that the costimulatory TNFR CD27 provides a dual trigger that can enhance survival of CD8 T cells, but also removal of activated CD8 T cells through Fas-driven apoptosis. Using in vitro stimulation assays of murine T cells with cognate peptide, we show that CD27 increases T cell survival after stimulation with low doses of Ag, whereas CD27 induces Fas-driven T cell apoptosis after stimulation with high doses of Ag. In vivo, the impact of constitutive CD70-driven stimulation on the accumulation of memory and effector CD8 T cells is limited by Fas-driven apoptosis. Furthermore, introduction of CD70 signaling during acute infection with influenza virus induces Fas-dependent elimination of influenza-specific CD8 T cells. These findings suggest that CD27 suppresses its costimulatory effects on T cell survival through activation of Fas-driven T cell apoptosis to maintain T cell homeostasis during infection.
Assuntos
Antígenos/imunologia , Apoptose/imunologia , Ligante CD27/imunologia , Linfócitos T CD8-Positivos/imunologia , Transdução de Sinais , Receptor fas/imunologia , Animais , Antígenos/genética , Antígenos/metabolismo , Apoptose/genética , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/imunologia , Proteínas Reguladoras de Apoptose/metabolismo , Proteína 11 Semelhante a Bcl-2 , Ligante CD27/genética , Ligante CD27/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Sobrevivência Celular/genética , Sobrevivência Celular/imunologia , Doença Crônica , Memória Imunológica/genética , Infecções/genética , Infecções/imunologia , Infecções/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/imunologia , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Knockout , Peptídeos/genética , Peptídeos/imunologia , Peptídeos/metabolismo , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/imunologia , Proteínas Proto-Oncogênicas/metabolismo , Membro 7 da Superfamília de Receptores de Fatores de Necrose Tumoral/genética , Membro 7 da Superfamília de Receptores de Fatores de Necrose Tumoral/imunologia , Membro 7 da Superfamília de Receptores de Fatores de Necrose Tumoral/metabolismo , Receptor fas/genética , Receptor fas/metabolismoRESUMO
BACKGROUND: Although distinct brain-homing B cells have been identified in multiple sclerosis (MS), it is unknown how these further evolve to contribute to local pathology. We explored B-cell maturation in the central nervous system (CNS) of MS patients and determined their association with immunoglobulin (Ig) production, T-cell presence, and lesion formation. METHODS: Ex vivo flow cytometry was performed on post-mortem blood, cerebrospinal fluid (CSF), meninges and white matter from 28 MS and 10 control brain donors to characterize B cells and antibody-secreting cells (ASCs). MS brain tissue sections were analysed with immunostainings and microarrays. IgG index and CSF oligoclonal bands were measured with nephelometry, isoelectric focusing, and immunoblotting. Blood-derived B cells were cocultured under T follicular helper-like conditions to evaluate their ASC-differentiating capacity in vitro. FINDINGS: ASC versus B-cell ratios were increased in post-mortem CNS compartments of MS but not control donors. Local presence of ASCs associated with a mature CD45low phenotype, focal MS lesional activity, lesional Ig gene expression, and CSF IgG levels as well as clonality. In vitro B-cell maturation into ASCs did not differ between MS and control donors. Notably, lesional CD4+ memory T cells positively correlated with ASC presence, reflected by local interplay with T cells. INTERPRETATION: These findings provide evidence that local B cells at least in late-stage MS preferentially mature into ASCs, which are largely responsible for intrathecal and local Ig production. This is especially seen in active MS white matter lesions and likely depends on the interaction with CD4+ memory T cells. FUNDING: Stichting MS Research (19-1057 MS; 20-490f MS), National MS Fonds (OZ2018-003).
Assuntos
Esclerose Múltipla , Substância Branca , Humanos , Esclerose Múltipla/metabolismo , Encéfalo/patologia , Células Produtoras de Anticorpos/metabolismo , Células Produtoras de Anticorpos/patologia , Substância Branca/patologia , Imunoglobulina G/metabolismoRESUMO
Differentiation of B cells into antibody-secreting cells (ASCs) is a key process to generate protective humoral immunity. A detailed understanding of the cues controlling ASC differentiation is important to devise strategies to modulate antibody formation. Here, we dissected differentiation trajectories of human naive B cells into ASCs using single-cell RNA sequencing. By comparing transcriptomes of B cells at different stages of differentiation from an in vitro model with ex vivo B cells and ASCs, we uncovered a novel pre-ASC population present ex vivo in lymphoid tissues. For the first time, a germinal-center-like population is identified in vitro from human naive B cells and possibly progresses into a memory B cell population through an alternative route of differentiation, thus recapitulating in vivo human GC reactions. Our work allows further detailed characterization of human B cell differentiation into ASCs or memory B cells in both healthy and diseased conditions.
Assuntos
Células Produtoras de Anticorpos , Linfócitos B , Humanos , Imunidade Humoral , Diferenciação Celular , Análise de Célula ÚnicaRESUMO
A Zika virus (ZIKV) infection during pregnancy can result in severe birth defects such as microcephaly. To date, it is incompletely understood how ZIKV can cross the human placenta. Furthermore, results from studies in pregnant mice and non-human primates are conflicting regarding the role of cross-reactive dengue virus (DENV) antibodies on transplacental ZIKV transmission. Elucidating how ZIKV can cross the placenta and which risk factors contribute to this is important for risk assessment and for potential intervention strategies for transplacental ZIKV transmission. In this study we use an ex vivo human placental perfusion model to study transplacental ZIKV transmission and the effect that cross-reactive DENV antibodies have on this transmission. By using this model, we demonstrate that DENV antibodies significantly increase ZIKV uptake in perfused human placentas and that this increased uptake is neonatal Fc-receptor-dependent. Furthermore, we show that cross-reactive DENV antibodies enhance ZIKV infection in term human placental explants and in primary fetal macrophages but not in primary trophoblasts. Our data supports the hypothesis that presence of cross-reactive DENV antibodies could be an important risk factor for transplacental ZIKV transmission. Furthermore, we demonstrate that the ex vivo placental perfusion model is a relevant and animal friendly model to study transplacental pathogen transmission.
Assuntos
Vírus da Dengue , Dengue , Infecção por Zika virus , Zika virus , Animais , Anticorpos Antivirais , Reações Cruzadas , Modelos Animais de Doenças , Feminino , Humanos , Camundongos , Placenta , GravidezRESUMO
High-affinity antibody-secreting cells (ASC) arise from terminal differentiation of B-cells after coordinated interactions with T follicular helper (Tfh) cells in germinal centers (GC). Elucidation of cues promoting human naive B-cells to progress into ASCs is challenging, as this process is notoriously difficult to induce in vitro while maintaining enough cell numbers to investigate the differentiation route(s). Here, we describe a minimalistic in vitro culture system that supports efficient differentiation of human naive B-cells into antibody-secreting cells. Upon initial stimulations, the interplay between level of CD40 costimulation and the Tfh cell-associated cytokines IL-21 and IL-4 determined the magnitude of B-cell expansion, immunoglobulin class-switching and expression of ASC regulator PRDM1. In contrast, the B-cell-specific transcriptional program was maintained, and efficient ASC formation was hampered. Renewed CD40 costimulation and Tfh cytokines exposure induced rapid secondary STAT3 signaling and extensive ASC differentiation, accompanied by repression of B-cell identity factors PAX5, BACH2 and IRF8 and further induction of PRDM1. Our work shows that, like in vivo, renewed CD40L costimulation also induces efficient terminal ASC differentiation after initial B-cell expansion in vitro. This culture system for efficient differentiation of human naive B-cells into ASCs, while also maintaining high cell numbers, may form an important tool in dissecting human naive B-cell differentiation, thereby enabling identification of novel transcriptional regulators and biomarkers for desired and detrimental antibody formation in humans.
Assuntos
Anticorpos/química , Linfócitos B/citologia , Células 3T3 , Animais , Formação de Anticorpos , Antígenos CD40/metabolismo , Diferenciação Celular , Citocinas/metabolismo , Ensaio de Imunoadsorção Enzimática , Regulação da Expressão Gênica , Centro Germinativo/imunologia , Humanos , Imunoglobulina G/imunologia , Imunoglobulina M/imunologia , Técnicas In Vitro , Ativação Linfocitária/imunologia , Camundongos , Células NIH 3T3 , Fosforilação , Fator 1 de Ligação ao Domínio I Regulador Positivo/metabolismo , Transdução de Sinais , Linfócitos T Auxiliares-Indutores/citologiaRESUMO
Growing evidence indicate that large antigen-containing particles induce potent T cell-dependent high-affinity antibody responses. These responses require large particle internalization after recognition by the B cell receptor (BCR) on B cells. However, the molecular mechanisms governing BCR-mediated internalization remain unclear. Here we use a high-throughput quantitative image analysis approach to discriminate between B cell particle binding and internalization. We systematically show, using small molecule inhibitors, that human B cells require a SYK-dependent IgM-BCR signaling transduction via PI3K to efficiently internalize large anti-IgM-coated particles. IgM-BCR-mediated activation of PI3K involves both the adaptor protein NCK and the co-receptor CD19. Interestingly, we here reveal a strong NCK-dependence without profound requirement of the co-receptor CD19 in B cell responses to large particles. Furthermore, we demonstrate that the IgM-BCR/NCK signaling event facilitates RAC1 activation to promote actin cytoskeleton remodeling necessary for particle engulfment. Thus, we establish NCK/PI3K/RAC1 as an attractive IgM-BCR signaling axis for biological intervention to prevent undesired antibody responses to large particles.
Assuntos
Apresentação de Antígeno/imunologia , Linfócitos B/imunologia , Ativação Linfocitária/imunologia , Fagocitose/imunologia , Transdução de Sinais/imunologia , Proteínas Adaptadoras de Transdução de Sinal/imunologia , Linfócitos B/metabolismo , Humanos , Imunoglobulina M/imunologia , Proteínas Oncogênicas/imunologia , Fosfatidilinositol 3-Quinases/imunologia , Receptores de Antígenos de Linfócitos B/imunologia , Proteínas rac1 de Ligação ao GTP/imunologiaRESUMO
Regulatory B cells (Breg) have been described as a specific immunological subsets in several mouse models. Identification of a human counterpart has remained troublesome, because unique plasma membrane markers or a defining transcription factor have not been identified. Consequently, human Bregs are still primarily defined by production of IL-10. In this study, we sought to elucidate if in vitro-induced human IL-10 producing B cells are a dedicated immunological subset. Using deep immune profiling by multicolor flow cytometry and t-SNE analysis, we show that the majority of cells induced to produce IL-10 co-express pro-inflammatory cytokines IL-6 and/or TNFα. No combination of markers can be identified to define human IL-10+TNFα-IL-6- B cells and rather point to a general activated B cell phenotype. Strikingly, upon culture and restimulation, a large proportion of formerly IL-10 producing B cells lose IL-10 expression, showing that induced IL-10 production is not a stable trait. The combined features of an activated B cell phenotype, transient IL-10 expression and lack of subset-defining markers suggests that in vitro-induced IL-10 producing B cells are not a dedicated subset of regulatory B cells.