ORCID Profile
0000-0001-5387-8413
Current Organisation
Garvan Institute of Medical Research
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Publisher: American Society for Clinical Investigation
Date: 06-06-2019
Publisher: Springer Science and Business Media LLC
Date: 10-03-2016
DOI: 10.1007/S10875-016-0257-6
Abstract: T follicular helper (Tfh) cells are a subset of effector CD4(+) T cells specialised to induce Ab production by B cells. This review highlights some of the recent advances in the field of human Tfh cells that have come from the study of primary immunodeficiencies. In particular it is increasingly evident that the quality of the Tfh cells that are generated, is just as important as the quantity.
Publisher: Wiley
Date: 05-2017
DOI: 10.1038/CTI.2017.17
Publisher: Springer US
Date: 2006
Publisher: American Society of Hematology
Date: 19-09-2013
DOI: 10.1182/BLOOD-2013-02-482331
Abstract: The development and survival of mature NKT cells are impaired in DOCK8-deficient mice. DOCK8 is required for antigen-induced NKT cell proliferation and cytokine production.
Publisher: Elsevier BV
Date: 03-2017
DOI: 10.1016/J.JACI.2016.07.016
Abstract: Dedicator of cytokinesis 8 (DOCK8) deficiency is a combined immunodeficiency caused by autosomal recessive loss-of-function mutations in DOCK8. This disorder is characterized by recurrent cutaneous infections, increased serum IgE levels, and severe atopic disease, including food-induced anaphylaxis. However, the contribution of defects in CD4 We sought to investigate the phenotype and function of DOCK8-deficient CD4 We performed in-depth analysis of the CD4 DOCK8-deficient memory CD4 Investigations into the DOCK8-deficient CD4
Publisher: Elsevier BV
Date: 07-2019
Publisher: Rockefeller University Press
Date: 09-04-2012
DOI: 10.1084/JEM.20112391
Abstract: Patients with the primary immunodeficiency X-linked lymphoproliferative disease (XLP), which is caused by mutations in SH2D1A, are highly susceptible to Epstein-Barr virus (EBV) infection. Nonetheless, some XLP patients demonstrate less severe clinical manifestations after primary infection. SH2D1A encodes the adaptor molecule SLAM-associated protein (SAP), which is expressed in T and natural killer cells and is required for cytotoxicity against B cells, the reservoir for EBV. It is not known why the clinical presentation of XLP is so variable. In this study, we report for the first time the occurrence of somatic reversion in XLP. Reverted SAP-expressing cells resided exclusively within the CD8+ T cell subset, displayed a CD45RA−CCR7− effector memory phenotype, and were maintained at a stable level over time. Importantly, revertant CD8+ SAP+ T cells, but not SAP− cells, proliferated in response to EBV and killed EBV-infected B cells. As somatic reversion correlated with EBV infection, we propose that the virus exerts a selective pressure on the reverted cells, resulting in their expansion in vivo and host protection against ongoing infection.
Publisher: Elsevier BV
Date: 02-2011
DOI: 10.1016/J.COI.2010.10.007
Abstract: CD4+ T cells can differentiate into numerous subsets characterized by expression of a suite of cytokines and effector molecules that endow them with specialized functions. By mediating the differentiation of B cells into memory and plasma cells following exposure to T-dependent antigens (Ag), T follicular helper (TFH) cells have emerged as the predominant subset of CD4+ T cells responsible for regulating humoral immunity. The generation of TFH cells from naïve precursors typically involves sequential cognate interactions with distinct populations of Ag-presenting cells (APCs): dendritic cells within the T-cell zone of lymphoid tissues, and activated B cells at the border of the T-zone and follicle, and then within a germinal center. Recent studies have illuminated the key roles of APCs in TFH development, and have also re-defined the role of B cells in this process.
Publisher: American Society for Clinical Investigation
Date: 04-09-2012
DOI: 10.1172/JCI62949
Publisher: The American Association of Immunologists
Date: 15-10-2002
DOI: 10.4049/JIMMUNOL.169.8.4298
Abstract: Isotype switching by murine B cells follows a pattern whereby the proportion of cells undergoing switching increases with ision number and is regulated by cytokines. Here we explored whether human B cells behaved in a similar manner. The effect of IL-4, IL-10, and IL-13, alone or in combination, on Ig isotype switching by highly purified naive human CD40 ligand (CD40L)-activated B cells was measured against ision number over various harvest times. Switching to IgG was induced by IL-4 and, to a lesser extent, IL-13 and IL-10. The combination of IL-10 with IL-4, but not IL-13, induced a higher percentage of cells to undergo switching. Isotype switching to IgG by human CD40L-activated naive B cells was found to be linked to the ision history of the cells: IgG+ cells appeared in cultures of B cells stimulated with CD40L and IL-4 after approximately the third cell ision, with the majority expressing IgG1, thus revealing a predictable pattern of IgG isotype switching. These results reveal a useful quantitative framework for monitoring the effects of cytokines on proliferation and isotype switching that should prove valuable for screening Ig immunodeficiencies and polymorphisms in the population for a better understanding of the regulation of human humoral immune responses.
Publisher: Elsevier BV
Date: 04-2011
DOI: 10.1016/J.IMMUNI.2011.01.021
Abstract: This study describes a CD4+ T helper (Th) cell subset marked by coexpression of the cytokine interleukin 21 (IL-21) and the gut-homing chemokine receptor CCR9. Although CCR9+ Th cells were observed in healthy mice and humans, they were enriched in the inflamed pancreas and salivary glands of NOD mice and in the circulation of Sjögren's syndrome patients. CCR9+ Th cells expressed large amounts of IL-21, inducible T cell costimulator (ICOS), and the transcription factors Bcl6 and Maf, and also supported antibody production from B cells, thereby resembling T follicular B helper (Tfh) cells. However, in contrast to Tfh cells, CCR9+ Th cells displayed limited expression of CXCR5 and the targets of CCR9+ Th cells were CD8+ T cells whose responsiveness to IL-21 was necessary for the development of diabetes. Thus, CCR9+ Th cells are a subset of IL-21-producing T helper cells that influence regional specification of autoimmune diseases that affect accessory organs of the digestive system.
Publisher: Springer Science and Business Media LLC
Date: 20-08-2018
Publisher: The American Association of Immunologists
Date: 15-09-2017
Abstract: Cytokine-mediated intracellular signaling pathways are fundamental for the development, activation, and differentiation of lymphocytes. These distinct processes underlie protection against infectious diseases after natural infection with pathogens or immunization, thereby providing the host with long-lived immunological memory. In contrast, aberrant cytokine signaling can also result in conditions of immune dysregulation, such as early-onset autoimmunity. Thus, balanced signals provided by distinct cytokines, and delivered to specific cell subsets, are critical for immune homeostasis. The essential roles of cytokines in human immunity have been elegantly and repeatedly revealed by the discovery of in iduals with mutations in cytokine ligands, receptors, and downstream transcription factors that cause primary immunodeficiency or autoimmune conditions. In this article, we review how the discovery and characterization of such in iduals has identified nonredundant, and often highly specialized, functions of specific cytokines and immune cell subsets in human lymphocyte biology, host defense against infections, and immune regulation.
Publisher: Wiley
Date: 30-01-2012
DOI: 10.1111/J.1749-6632.2011.06361.X
Abstract: Regulated interactions between cells of the immune system facilitate the generation of successful immune responses, thereby enabling efficient neutralization and clearance of pathogens and the establishment of both cell- and humoral-mediated immunological memory. The corollary of this is that impediments to efficient cell-cell interactions, normally necessary for differentiation and effector functions of immune cells, underly the clinical features and disease pathogenesis of primary immunodeficiencies. In affected in iduals, these defects manifest as impaired long-term humoral immunity and susceptibility to infection by specific pathogens. In this review, we discuss the importance of, and requirements for, effective interactions between B cells and T cells during the formation of CD4(+) T follicular helper cells and the elicitation of cytotoxic function of virus-specific CD8(+) T cells, as well as how these processes are abrogated in primary immunodeficiencies due to loss-of-function mutations in defined genes.
Publisher: Wiley
Date: 08-06-2010
DOI: 10.1038/ICB.2010.73
Publisher: Informa UK Limited
Date: 2013
DOI: 10.3109/08880019409140540
Abstract: Two cases of juvenile classic Kaposi's sarcoma (KS), one with family history, are described, and the natural history of KS is briefly reviewed. Case 1a was a child whose disease ran an aggressive course and did not respond to therapy. Case 1b was the mother of the child: She had a relapsed localized form that was treated by surgery and chemotherapy, and she has been disease free since 1990. The second juvenile case was a 4-year-old boy with a localized form that relapsed but was successfully treated by surgery, chemotherapy, and radiation therapy. He has been free of disease since 1986. Family history in juvenile KS has not previously been reported unrelated to acquired immunodeficiency syndrome in a Western country.
Publisher: Wiley
Date: 17-01-2005
DOI: 10.1111/J.0105-2896.2005.00230.X
Abstract: X-linked lymphoproliferative disease (XLP) is an inherited immune defect caused by mutations in the Src homology 2 domain-containing gene 1A, which encodes the adapter protein, signaling lymphocytic activation molecule (SLAM)-associated protein (SAP). SAP is expressed in T cells, natural killer (NK) cells, and NKT cells, where it binds to the cytoplasmic domain of the surface receptor SLAM (CD150) and the related receptors, 2B4 (CD244), CD84, Ly9 (CD229), NK-T-B-antigen, and CD2-like receptor-activating cytotoxic T cells. SAP also binds to the Src family tyrosine kinase Fyn and recruits it to SLAM, which leads to the generation of downstream phosphotyrosine signals. While the roles of the SLAM family receptors are only beginning to be understood, experiments suggest that these molecules regulate important aspects of lymphocyte function, such as proliferation, cytokine secretion, cytotoxicity, and antibody production. Thus, in XLP patients who lack functional SAP, the SLAM family receptors may not signal properly. This property likely contributes to the phenotypes of XLP, including fulminant infectious mononucleosis, lymphoma, and hypogammaglobulinemia. Further studies of SAP and the SLAM family receptors will provide insights into XLP and elucidate the signaling events regulating lymphocyte ontogeny and function.
Publisher: Rockefeller University Press
Date: 30-06-2008
DOI: 10.1084/JEM.20080218
Abstract: Hyper–immunoglobulin E syndrome (HIES) is a primary immune deficiency characterized by abnormal and devastating susceptibility to a narrow spectrum of infections, most commonly Staphylococcus aureus and Candida albicans. Recent investigations have identified mutations in STAT3 in the majority of HIES patients studied. Despite the identification of the genetic cause of HIES, the mechanisms underlying the pathological features of this disease remain to be elucidated. Here, we demonstrate a failure of CD4+ T cells harboring heterozygous STAT3 mutations to generate interleukin 17–secreting (i.e., T helper [Th]17) cells in vivo and in vitro due to a failure to express sufficient levels of the Th17-specific transcriptional regulator retinoid-related orphan receptor γt. Because Th17 cells are enriched for cells with specificities against fungal antigens, our results may explain the pattern of infection susceptibility characteristic of patients with HIES. Furthermore, they underscore the importance of Th17 responses in normal host defense against the common pathogens S. aureus and C. albicans.
Publisher: Elsevier BV
Date: 03-2018
Publisher: Wiley
Date: 07-08-2017
DOI: 10.1111/IMM.12793
Publisher: American Society for Clinical Investigation
Date: 09-2021
DOI: 10.1172/JCI150143
Publisher: American Society for Clinical Investigation
Date: 2017
DOI: 10.1172/JCI90727DS1
Publisher: American Society for Clinical Investigation
Date: 17-04-2017
DOI: 10.1172/JCI90727
Publisher: Springer Science and Business Media LLC
Date: 10-2018
Publisher: Wiley
Date: 22-10-2013
DOI: 10.1038/ICB.2013.55
Abstract: The generation of protective antibodies by B cells following natural infection or vaccination requires 'help' from CD4(+) T cells. T follicular helper (Tfh) cells are the specialized CD4(+) T cell subset that has evolved the appropriate mechanisms to induce the activation and differentiation of B cells into immunoglobulin (Ig) secreting cells. As such, appropriate control of Tfh cell generation and function is essential to human health as overactivation is likely to result in autoimmunity, whereas underactivation is often associated with immunodeficiency. Furthermore, an understanding of the regulation of these cells may be invaluable to improved vaccine development strategies. Traditionally Tfh cells have been identified by their anatomical location in secondary lymphoid tissues, which has hindered the study of these cells in humans as access to these tissues is often not feasible. However, recent studies have identified the circulating counterparts to tissue Tfh cells and with this has come a wealth of knowledge gained from the study of these cells in human disease. Here we review some of the recent developments on the role of human Tfh cells in health and disease.
Publisher: Wiley
Date: 08-03-2019
DOI: 10.1111/IMCB.12243
Abstract: Inherited defects in genes encoding for proteins that are involved in the assembly and dynamics of the actin skeleton have increasingly been identified in patients presenting with primary immunodeficiencies. In this review, we summarize a subset of the recently described conditions, emphasizing the clinical features as well as the immunophenotype and pathophysiology.
Publisher: Elsevier BV
Date: 06-2023
Publisher: Springer Science and Business Media LLC
Date: 28-06-2021
Publisher: American Society for Clinical Investigation
Date: 2013
DOI: 10.1172/JCI71927DS1
Publisher: American Society of Hematology
Date: 08-2008
DOI: 10.1182/BLOOD-2007-10-116269
Abstract: Epstein-Barr virus (EBV) persists in healthy virus carriers within the immunoglobulin (Ig)D−CD27+ (class-switched) memory B-cell compartment that normally arises through antigen stimulation and germinal center transit. Patients with X-linked lymphoproliferative disease (XLP) lack such class-switched memory B cells but are highly susceptible to EBV infection, often developing fatal symptoms resembling those seen in EBV-associated hemophagocytic syndrome (EBV-AHS), a disease caused by aberrant virus entry into the NK- or T-cell system. Here we show that XLP patients who survive primary EBV exposure carry relatively high virus loads in the B-cell, but not the NK- or T-cell, compartment. Interestingly, in the absence of conventional class-switched memory B cells, the circulating EBV load was concentrated within a small population of IgM+IgD+CD27+ (nonswitched) memory cells rather than within the numerically dominant naive (IgM+IgD+CD27−) or transitional (CD10+CD27−) subsets. In 2 prospectively studied patients, the circulating EBV load was stable and markers of virus polymorphism detected the same resident strain over time. These results provide the first definitive evidence that EBV can establish persistence in the B-cell system in the absence of fully functional germinal center activity and of a class-switched memory B-cell compartment.
Publisher: The American Association of Immunologists
Date: 08-2008
DOI: 10.4049/JIMMUNOL.181.3.1767
Abstract: Naive B cells can alter the effector function of their Ig molecule by isotype switching, thereby allowing them to secrete not only IgM, but also the switched isotypes IgG, IgA, and IgE. Different isotypes are elicited in response to specific pathogens. Similarly, dysregulated production of switched isotypes underlies the development of various diseases, such as autoimmunity and immunodeficiency. Thus, it is important to characterize mediators controlling isotype switching, as well as their contribution to the overall B cell response. Isotype switching in human naive B cells can be induced by CD40L together with IL-4, IL-10, IL-13, and/or TGF-β. Recently, IL-21 was identified as a switch factor for IgG1 and IgG3. However, the effect of IL-21 on switching to IgA, as well as the interplay between IL-21 and other switch factors, remains unknown. We found that IL-4 and IL-21 in idually induced CD40L-stimulated human naive B cells to undergo switching to IgG, with IL-4 predominantly inducing IgG1+ cells and IL-21 inducing IgG3. Culture of naive B cells with CD40L and IL-21, but not IL-4, also yielded IgA+ cells. Combining IL-4 and IL-21 had ergent effects on isotype switching. Specifically, while IL-4 and IL-21 synergistically increased the generation of IgG1+ cells from CD40L-stimulated B cells, IL-4 concomitantly abolished IL-21-induced switching to IgA. Our findings demonstrate the dynamic interplay between IL-4 and IL-21 in regulating the production of IgG subclasses and IgA, and suggest temporal roles for these cytokines in humoral immune responses to specific pathogens.
Publisher: American Society of Hematology
Date: 26-04-2012
DOI: 10.1182/BLOOD-2011-11-392985
Abstract: T follicular helper (Tfh) cells are critical for providing the necessary signals to induce differentiation of B cells into memory and Ab-secreting cells. Accordingly, it is important to identify the molecular requirements for Tfh cell development and function. We previously found that IL-12 mediates the differentiation of human CD4+ T cells to the Tfh lineage, because IL-12 induces naive human CD4+ T cells to acquire expression of IL-21, BCL6, ICOS, and CXCR5, which typify Tfh cells. We have now examined CD4+ T cells from patients deficient in IL-12Rβ1, TYK2, STAT1, and STAT3 to further explore the pathways involved in human Tfh cell differentiation. Although STAT1 was dispensable, mutations in IL12RB1, TYK2, or STAT3 compromised IL-12–induced expression of IL-21 by human CD4+ T cells. Defective expression of IL-21 by STAT3-deficient CD4+ T cells resulted in diminished B-cell helper activity in vitro. Importantly, mutations in STAT3, but not IL12RB1 or TYK2, also reduced Tfh cell generation in vivo, evidenced by decreased circulating CD4+CXCR5+ T cells. These results highlight the nonredundant role of STAT3 in human Tfh cell differentiation and suggest that defective Tfh cell development and/or function contributes to the humoral defects observed in STAT3-deficient patients.
Publisher: Springer Science and Business Media LLC
Date: 11-2018
DOI: 10.1007/S10875-018-0570-3
Abstract: The original version of this article unfortunately did not display the appropriate captions in the figure. The correct version is displayed below.
Publisher: Wiley
Date: 04-11-2011
Publisher: Oxford University Press (OUP)
Date: 23-05-2006
Abstract: X-linked lymphoproliferative disease (XLP) is an immunodeficiency resulting from mutations in SH2D1A, which encodes signalling lymphocytic activation molecule (SLAM)-associated protein (SAP). In addition to SLAM, SAP associates with several other cell-surface receptors including 2B4 (CD244), Ly9 (CD229), CD84 and NTB-A. SAP contains a single src-homology-2 domain and acts as an intracellular adaptor protein by recruiting the protein tyrosine kinase FynT to the cytoplasmic domains of some of these receptors, which results in the initiation of specific downstream signal transduction pathways. XLP is likely to result from perturbed signalling through one or more of these SAP-associating receptors. In this study, we identified missense (Y54C, I84T and F87S) and insertion (fs82 --> X103) mutations in four different kindreds affected by XLP. Each mutation dramatically reduced the half-life of SAP, thus diminishing its expression in primary lymphocytes as well as in transfected cell lines. Interestingly, although the Y54C and F87S mutations compromised the ability of SAP to associate with different receptors, the I84T mutation had no effect on the ability of SAP to bind SLAM, CD84 or 2B4. However, signalling downstream of SLAM was reduced in the presence of SAP bearing the I84T mutation. These findings indicate that, irrespective of the type of mutation, signalling through SAP-associating receptors in XLP can be impaired by reducing the expression of SAP, the ability of SAP to bind surface receptors and/or its ability to activate signal transduction downstream of the SLAM-SAP complex.
Publisher: Elsevier BV
Date: 12-2020
Publisher: Wiley
Date: 23-02-2016
Publisher: Elsevier BV
Date: 10-2015
Publisher: American Association for the Advancement of Science (AAAS)
Date: 29-10-2021
DOI: 10.1126/SCIIMMUNOL.ABH0891
Abstract: [Figure: see text].
Publisher: Wiley
Date: 30-10-2015
Publisher: Rockefeller University Press
Date: 19-09-2016
DOI: 10.1084/JEM.20160576
Abstract: Combined immunodeficiency (CID) refers to inborn errors of human T cells that also affect B cells because of the T cell deficit or an additional B cell–intrinsic deficit. In this study, we report six patients from three unrelated families with biallelic loss-of-function mutations in RLTPR, the mouse orthologue of which is essential for CD28 signaling. The patients have cutaneous and pulmonary allergy, as well as a variety of bacterial and fungal infectious diseases, including invasive tuberculosis and mucocutaneous candidiasis. Proportions of circulating regulatory T cells and memory CD4+ T cells are reduced. Their CD4+ T cells do not respond to CD28 stimulation. Their CD4+ T cells exhibit a "Th2" cell bias ex vivo and when cultured in vitro, contrasting with the paucity of "Th1," "Th17," and T follicular helper cells. The patients also display few memory B cells and poor antibody responses. This B cell phenotype does not result solely from the T cell deficiency, as the patients’ B cells fail to activate NF-κB upon B cell receptor (BCR) stimulation. Human RLTPR deficiency is a CID affecting at least the CD28-responsive pathway in T cells and the BCR-responsive pathway in B cells.
Publisher: Rockefeller University Press
Date: 11-07-2016
DOI: 10.1084/JEM.20151467
Abstract: Naive CD4+ T cells differentiate into specific effector subsets—Th1, Th2, Th17, and T follicular helper (Tfh)—that provide immunity against pathogen infection. The signaling pathways involved in generating these effector cells are partially known. However, the effects of mutations underlying human primary immunodeficiencies on these processes, and how they compromise specific immune responses, remain unresolved. By studying in iduals with mutations in key signaling pathways, we identified nonredundant pathways regulating human CD4+ T cell differentiation in vitro. IL12Rβ1/TYK2 and IFN-γR/STAT1 function in a feed-forward loop to induce Th1 cells, whereas IL-21/IL-21R/STAT3 signaling is required for Th17, Tfh, and IL-10–secreting cells. IL12Rβ1/TYK2 and NEMO are also required for Th17 induction. Strikingly, gain-of-function STAT1 mutations recapitulated the impact of dominant-negative STAT3 mutations on Tfh and Th17 cells, revealing a putative inhibitory effect of hypermorphic STAT1 over STAT3. These findings provide mechanistic insight into the requirements for human T cell effector function, and explain clinical manifestations of these immunodeficient conditions. Furthermore, they identify molecules that could be targeted to modulate CD4+ T cell effector function in the settings of infection, vaccination, or immune dysregulation.
Publisher: Elsevier BV
Date: 05-2015
DOI: 10.1016/J.IMMUNI.2015.04.010
Abstract: The mechanistic links between genetic variation and autoantibody production in autoimmune disease remain obscure. Autoimmune lymphoproliferative syndrome (ALPS) is caused by inactivating mutations in FAS or FASL, with autoantibodies thought to arise through failure of FAS-mediated removal of self-reactive germinal center (GC) B cells. Here we show that FAS is in fact not required for this process. Instead, FAS inactivation led to accumulation of a population of unconventional GC B cells that underwent somatic hypermutation, survived despite losing antigen reactivity, and differentiated into a large population of plasma cells that included autoantibody-secreting clones. IgE(+) plasma cell numbers, in particular, increased after FAS inactivation and a major cohort of ALPS-affected patients were found to have hyper-IgE. We propose that these previously unidentified cells, designated "rogue GC B cells," are a major driver of autoantibody production and provide a mechanistic explanation for the linked production of IgE and autoantibodies in autoimmune disease.
Publisher: Springer Science and Business Media LLC
Date: 17-05-2013
DOI: 10.1038/NRI3447
Abstract: Antibody production is an important feature of the vertebrate immune system. Antibodies neutralize and clear pathogens, thereby protecting against infectious diseases. Such humoral immunity has great longevity, often persisting for the host's lifetime. Long-lived humoral immunity depends on help provided by CD4(+) T cells, namely T follicular helper (TFH) cells, which support the differentiation of antigen-specific B cells into memory and plasma cells. TFH cells are stringently regulated, as aberrant TFH cell activity is involved in immunopathologies such as autoimmunity, immunodeficiencies and lymphomas. The elucidation of the mechanisms that regulate TFH cell differentiation, function and fate should highlight targets for novel therapeutics.
Publisher: American Society of Hematology
Date: 05-12-2013
DOI: 10.1182/BLOOD-2013-06-506865
Abstract: IL21-mediated induction of CD25 expression on naïve human B cells requires STAT3. A lack of response to IL-2 may lify humoral immunodeficiency in patients with STAT3, IL2RG, or IL21R mutations due to unresponsiveness to IL21.
Publisher: Rockefeller University Press
Date: 02-07-2012
DOI: 10.1084/JEM.20120994
Abstract: The generation of high-affinity antibodies (Abs) plays a critical role in the neutralization and clearance of pathogens and subsequent host survival after natural infection with a variety of microorganisms. Most currently available vaccines rely on the induction of long-lived protective humoral immune responses by memory B cells and plasma cells, underscoring the importance of Abs in host protection. Ab responses against most antigens (Ags) require interactions between B cells and CD4+ T helper cells, and it is now well recognized that T follicular helper cells (Tfh) specialize in providing cognate help to B cells and are fundamentally required for the generation of T cell–dependent B cell responses. Perturbations in the development and/or function of Tfh cells can manifest as immunopathologies, such as immunodeficiency, autoimmunity, and malignancy. Unraveling the cellular and molecular requirements underlying Tfh cell formation and maintenance will help to identify molecules that could be targeted for the treatment of immunological diseases that are characterized by insufficient or excessive Ab responses.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 14-12-2018
DOI: 10.1126/SCIIMMUNOL.AAU6759
Abstract: Human IFN-γ–dependent immunity to mycobacteria is less compromised in IL-12Rβ2 or IL-23R deficiency than IL-12Rβ1 deficiency.
Publisher: Rockefeller University Press
Date: 21-03-2023
DOI: 10.1084/JEM.20221020
Abstract: Heterozygous loss-of-function (LOF) mutations in PIK3R1 (encoding phosphatidylinositol 3-kinase [PI3K] regulatory subunits) cause activated PI3Kδ syndrome 2 (APDS2), which has a similar clinical profile to APDS1, caused by heterozygous gain-of-function (GOF) mutations in PIK3CD (encoding the PI3K p110δ catalytic subunit). While several studies have established how PIK3CD GOF leads to immune dysregulation, less is known about how PIK3R1 LOF mutations alter cellular function. By studying a novel CRISPR/Cas9 mouse model and patients’ immune cells, we determined how PIK3R1 LOF alters cellular function. We observed some overlap in cellular defects in APDS1 and APDS2, including decreased intrinsic B cell class switching and defective Tfh cell function. However, we also identified unique APDS2 phenotypes including defective expansion and affinity maturation of Pik3r1 LOF B cells following immunization, and decreased survival of Pik3r1 LOF pups. Further, we observed clear differences in the way Pik3r1 LOF and Pik3cd GOF altered signaling. Together these results demonstrate crucial differences between these two genetic etiologies.
Publisher: Elsevier BV
Date: 06-2019
Publisher: American Society for Clinical Investigation
Date: 02-2021
DOI: 10.1172/JCI142434
Publisher: Elsevier BV
Date: 10-2021
DOI: 10.1016/J.COI.2021.06.011
Abstract: The production of high-affinity antibodies is a key feature of the vertebrate immune system. Antibodies neutralize and clear pathogens, thereby protecting against infectious diseases. However, dysregulated production of antibodies can cause immune pathologies, such as autoimmunity and immune deficiency. Long-lived humoral immunity depends on B-cell help provided by T follicular helper (Tfh) cells, which support the differentiation of antigen (Ag)-specific B cells into memory and plasma cells. Tfh cells are generated from naïve CD4
Publisher: American Society of Hematology
Date: 03-12-2020
Abstract: Biallelic mutations in the genes encoding CD27 or its ligand CD70 underlie inborn errors of immunity (IEIs) characterized predominantly by Epstein-Barr virus (EBV)-associated immune dysregulation, such as chronic viremia, severe infectious mononucleosis, hemophagocytic lymphohistiocytosis (HLH), lymphoproliferation, and malignancy. A comprehensive understanding of the natural history, immune characteristics, and transplant outcomes has remained elusive. Here, in a multi-institutional global collaboration, we collected the clinical information of 49 patients from 29 families (CD27, n = 33 CD70, n = 16), including 24 previously unreported in iduals and identified a total of 16 distinct mutations in CD27, and 8 in CD70, respectively. The majority of patients (90%) were EBV+ at diagnosis, but only ∼30% presented with infectious mononucleosis. Lymphoproliferation and lymphoma were the main clinical manifestations (70% and 43%, respectively), and 9 of the CD27-deficient patients developed HLH. Twenty-one patients (43%) developed autoinflammatory features including uveitis, arthritis, and periodic fever. Detailed immunological characterization revealed aberrant generation of memory B and T cells, including a paucity of EBV-specific T cells, and impaired effector function of CD8+ T cells, thereby providing mechanistic insight into cellular defects underpinning the clinical features of disrupted CD27/CD70 signaling. Nineteen patients underwent allogeneic hematopoietic stem cell transplantation (HSCT) prior to adulthood predominantly because of lymphoma, with 95% survival without disease recurrence. Our data highlight the marked predisposition to lymphoma of both CD27- and CD70-deficient patients. The excellent outcome after HSCT supports the timely implementation of this treatment modality particularly in patients presenting with malignant transformation to lymphoma.
Publisher: Rockefeller University Press
Date: 05-06-2023
DOI: 10.1084/JEM.20221105
Abstract: B cells develop from hematopoietic stem cells in the bone marrow. Once generated, they serve multiple roles in immune regulation and host defense. However, their most important function is producing antibodies (Ab) that efficiently clear invading pathogens. This is achieved by generating memory B cells that rapidly respond to subsequent Ag exposure, and plasma cells (PCs) that continually secrete Ab. These B cell subsets maintain humoral immunity and host protection against recurrent infections for extended periods of time. Thus, the generation of antigen (Ag)-specific memory cells and PCs underlies long-lived serological immunity, contributing to the success of most vaccines. Our understanding of immunity is often derived from animal models. However, analysis of in iduals with monogenic defects that disrupt immune cell function are unprecedented models to link genotypes to clinical phenotypes, establish mechanisms of disease pathogenesis, and elucidate critical pathways for immune cell development and differentiation. Here, we review fundamental breakthroughs in unraveling the complexities of humoral immunity in humans that have come from the discovery of inborn errors disrupting B cell function.
Publisher: Annual Reviews
Date: 04-2007
DOI: 10.1146/ANNUREV.IMMUNOL.25.022106.141651
Abstract: SAP (SLAM-associated protein) was identified in 1998 as an adaptor molecule involved in the intracellular signaling pathways elicited through the cell surface receptor SLAM and as the protein defective in the human immunodeficiency X-linked lymphoproliferative disease (XLP). During the past eight years, it has been established that the SLAM family of cell surface receptors (SLAM, 2B4, NTB-A, Ly9, CD84) and the SAP family of adaptors (SAP, EAT-2, ERT) play critical roles in lymphocyte development, differentiation, and acquisition of effector functions. Studies of these proteins have shown unexpected roles in cytokine production by T cells and myeloid cells, T cell–dependent humoral immune responses, NK cell–mediated cytotoxicity, and NKT cell development. This review highlights recent findings that have improved our understanding of the roles of the SLAM and SAP families of molecules in immune regulation and discusses how perturbations in the signaling pathways involving these proteins can result in different disease states.
Publisher: Elsevier BV
Date: 08-2010
Publisher: Wiley
Date: 02-2004
DOI: 10.1046/J.0818-9641.2003.01206.X
Abstract: Lymphocyte differentiation is a complex process regulated by the integration of signals received through a variety of cell surface receptors that results in populations of differentiated cells that have acquired novel characteristics and effector functions. Differentiation of T and B lymphocytes into effector cells, such as cytokine-secreting CD4+ T cells, cytotoxic CD8+ T cells and Ig-secreting B cells, as well as alterations in cell surface phenotype, have been reported to be associated with cell ision. Nevertheless, the genesis of heterogeneity in effector cell type is unknown. A strictly deterministic view holds that heterogeneity arises from distinct signalling histories for each functionally or phenotypically different cell type. In contrast, a probabilistic interpretation proposes that internal stochastic regulation of gene expression gives rise to lymphocytes of mixed phenotypes. To help distinguish between these explanations, we examined the expression of CD27, CCR7, CD45RA and CD45RO by human naive CD4+ T cells in the context of the ision history of the lymphocyte. Our results show that each marker independently changes with progressive isions, strongly supporting the proposal that phenotypic heterogeneity in lymphocytes can arise as the result of independent stochastic processes controlling the expression of in idual molecules.
Publisher: The American Association of Immunologists
Date: 15-12-2007
DOI: 10.4049/JIMMUNOL.179.12.8180
Abstract: Differentiation of B cells into Ig-secreting cells (ISC) is critical for the generation of protective humoral immune responses. Because of the important role played by secreted Ig in host protection against infection, it is necessary to identify molecules that control B cell differentiation. Recently, IL-21 was reported to generate ISC from activated human B cells. In this study, we examined the effects of IL-21 on the differentiation of all human mature B cell subsets—neonatal, transitional, naive, germinal center, IgM-memory, and isotype-switched memory cells—into ISC and compared its efficacy to that of IL-10, a well-known mediator of human B cell differentiation. IL-21 rapidly induced the generation of ISC and the secretion of vast quantities IgM, IgG and IgA from all of these B cell subsets. Its effect exceeded that of IL-10 by up to 100-fold, highlighting the potency of IL-21 as a B cell differentiation factor. Strikingly, IL-4 suppressed the stimulatory effects of IL-21 on naive B cells by reducing the expression of B-lymphocyte induced maturation protein-1 (Blimp-1). In contrast, memory B cells were resistant to the inhibitory effects of IL-4. Finally, the ability of human tonsillar CD4+CXCR5+CCR7− T follicular helper (TFH) cells, known to be a rich source of IL-21, to induce the differentiation of autologous B cells into ISC was mediated by the production of IL-21. These findings suggest that IL-21 produced by TFH cells during the primary as well as the subsequent responses to T cell-dependent Ag makes a major contribution to eliciting and maintaining long-lived humoral immunity.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 08-06-2018
DOI: 10.1126/SCIIMMUNOL.AAT4956
Abstract: ZNF341 is a newly characterized transcription factor controlling baseline and inducible transcription of the human STAT3 gene.
Publisher: Rockefeller University Press
Date: 11-11-2013
DOI: 10.1084/JEM.20130323
Abstract: Long-lived antibody memory is mediated by the combined effects of long-lived plasma cells (PCs) and memory B cells generated in response to T cell–dependent antigens (Ags). IL-10 and IL-21 can activate multiple signaling pathways, including STAT1, STAT3, and STAT5 ERK PI3K/Akt, and potently promote human B cell differentiation. We previously showed that loss-of-function mutations in STAT3, but not STAT1, abrogate IL-10– and IL-21–mediated differentiation of human naive B cells into plasmablasts. We report here that, in contrast to naive B cells, STAT3-deficient memory B cells responded to these STAT3-activating cytokines, differentiating into plasmablasts and secreting high levels of IgM, IgG, and IgA, as well as Ag-specific IgG. This was associated with the induction of the molecular machinery necessary for PC formation. Mutations in IL21R, however, abolished IL-21–induced responses of both naive and memory human B cells and compromised memory B cell formation in vivo. These findings reveal a key role for IL-21R/STAT3 signaling in regulating human B cell function. Furthermore, our results indicate that the threshold of STAT3 activation required for differentiation is lower in memory compared with naive B cells, thereby identifying an intrinsic difference in the mechanism underlying differentiation of naive versus memory B cells.
Publisher: Springer Science and Business Media LLC
Date: 27-09-2016
DOI: 10.1038/NCOMMS3523
Publisher: American Association for the Advancement of Science (AAAS)
Date: 11-2019
DOI: 10.1126/SCIIMMUNOL.AAX7965
Abstract: Human JNK1 is essential for IL-17A/F–dependent mucocutaneous immunity to Candida and for TGF-β–dependent homeostasis of connective tissues.
Publisher: Elsevier BV
Date: 09-2009
DOI: 10.1016/J.IMMUNI.2009.07.002
Abstract: Follicular helper T (Tfh) cells provide selection signals to germinal center B cells, which is essential for long-lived antibody responses. High CXCR5 and low CCR7 expression facilitates their homing to B cell follicles and distinguishes them from T helper 1 (Th1), Th2, and Th17 cells. Here, we showed that Bcl-6 directs Tfh cell differentiation: Bcl-6-deficient T cells failed to develop into Tfh cells and could not sustain germinal center responses, whereas forced expression of Bcl-6 in CD4(+) T cells promoted expression of the hallmark Tfh cell molecules CXCR5, CXCR4, and PD-1. Bcl-6 bound to the promoters of the Th1 and Th17 cell transcriptional regulators T-bet and RORgammat and repressed IFN-gamma and IL-17 production. Bcl-6 also repressed expression of many microRNAs (miRNAs) predicted to control the Tfh cell signature, including miR-17-92, which repressed CXCR5 expression. Thus, Bcl-6 positively directs Tfh cell differentiation, through combined repression of miRNAs and transcription factors.
Publisher: American Society for Clinical Investigation
Date: 19-01-2006
DOI: 10.1172/JCI25720
Publisher: American Society for Clinical Investigation
Date: 03-03-2005
DOI: 10.1172/JCI200523139
Publisher: Springer Science and Business Media LLC
Date: 13-02-2005
DOI: 10.1038/NM1189
Abstract: The adaptor molecule SAP is expressed in T lymphocytes and natural killer (NK) cells, where it regulates cytokine production and cytotoxicity. Here, we show that SAP, encoded by the SH2D1A gene locus, also has a crucial role during the development of NKT cells, a lymphocyte subset with immunoregulatory functions in response to infection, cancer and autoimmune disease. Following stimulation with the NKT cell-specific agonist alpha-galactosyl ceramide (alphaGC), Sh2d1a-/- splenocytes did not produce cytokines or activate other lymphoid lineages in an NKT cell-dependent manner. While evaluating the abnormalities in alphaGC-induced immune responses, we observed that Sh2d1a-/- animals lacked NKT cells in the thymus and peripheral organs. The defect in NKT cell ontogeny was hematopoietic cell autonomous and could be rescued by reconstitution of SAP expression within Sh2d1a-/- bone marrow cells. Seventeen in iduals with X-linked lymphoproliferative disease (XLP), who harbored germline mutations in SH2D1A, also lacked NKT cells. Furthermore, a female XLP carrier showed completely skewed X chromosome inactivation within NKT cells, but not T or B cells. Thus, SAP is a crucial regulator of NKT cell ontogeny in humans and in mice. The absence of NKT cells may contribute to the phenotypes of SAP deficiency, including abnormal antiviral and antitumor immunity and hypogammaglobulinemia.
Publisher: Elsevier BV
Date: 09-2005
DOI: 10.1016/0092-8674(92)90308-Y
Abstract: We have generated mutant mice that do not express pp59fyn, a nonreceptor protein tyrosine kinase related to pp60src, by homologous recombination in embryonic stem cells. fyn- mice did not display an overt phenotype. Because fyn is associated with the T cell receptor (TCR), thymocyte and T cell signaling was analyzed in the mutant background. Cross-linking of TCR-CD3 in thymocytes led to markedly reduced calcium fluxes and abrogated proliferation, whereas mature splenic T cells retained largely normal proliferation despite depressed calcium movements and IL-2 production. Similarly, proliferation induced by Thy-1 cross-linking was reduced in thymocytes but not in splenic T cells. fyn- thymocytes were impaired at a late stage of maturation and showed limited clonal deletion to the Mls-1a self-super-antigen but not to staphylococcal enterotoxin A. These results implicate fyn as a critical component in TCR signaling in thymocytes and, potentially, in the process that determines T cell repertoire in the adult mouse.
Publisher: Wiley
Date: 16-04-2020
DOI: 10.1002/CYTO.A.24018
Publisher: American Association for the Advancement of Science (AAAS)
Date: 14-12-2018
DOI: 10.1126/SCIIMMUNOL.AAU8714
Abstract: Homozygosity for the P1104A missense variant of the TYK2 Janus kinase is common monogenic etiology of primary tuberculosis.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 07-08-2015
Abstract: The immune system needs its full array of soldiers—including cells and the molecules they secrete—to optimally protect the host. When this isn't the case, minor infections can become chronic or even deadly. Markle et al. report the discovery of seven in iduals carrying loss-of-function mutations in RORC, which encodes the transcription factors RORγ and RORγT. These in iduals lacked immune cells that produce the cytokine interleukin-17, causing them to suffer from chronic candidiasis. RORC-deficient in iduals also exhibited impaired immunity to mycobacterium, probably due to reduced production of the cytokine interferon-γ, a molecule not known to require RORC for its induction. Science , this issue p. 606
Publisher: The American Association of Immunologists
Date: 15-09-2017
Abstract: Mutations in the dedicator of cytokinesis 8 (DOCK8) gene cause an autosomal recessive form of hyper-IgE syndrome, characterized by chronic immunodeficiency with persistent microbial infection and increased incidence of malignancy. These manifestations suggest a defect in cytotoxic lymphocyte function and immune surveillance. However, how DOCK8 regulates NK cell–driven immune responses remains unclear. In this article, we demonstrate that DOCK8 regulates NK cell cytotoxicity and cytokine production in response to target cell engagement or receptor ligation. Genetic ablation of DOCK8 in human NK cells attenuated cytokine transcription and secretion through inhibition of Src family kinase activation, particularly Lck, downstream of target cell engagement or NKp30 ligation. PMA/Ionomycin treatment of DOCK8-deficient NK cells rescued cytokine production, indicating a defect proximal to receptor ligation. Importantly, NK cells from DOCK8-deficient patients had attenuated production of IFN-γ and TNF-α upon NKp30 stimulation. Taken together, we reveal a novel molecular mechanism by which DOCK8 regulates NK cell–driven immunity.
Publisher: Springer Science and Business Media LLC
Date: 22-08-2018
DOI: 10.1038/S41467-018-05772-7
Abstract: 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.
Publisher: Springer Science and Business Media LLC
Date: 27-04-2007
Publisher: Springer Science and Business Media LLC
Date: 05-08-2015
DOI: 10.1038/NI1497
Abstract: T(H)-17 cells are a distinct lineage of proinflammatory T helper cells that are essential for autoimmune disease. In mice, commitment to the T(H)-17 lineage is dependent on transforming growth factor-beta and interleukin 6 (IL-6). Here we demonstrate that IL-23 and IL-1beta induced the development of human T(H)-17 cells expressing IL-17A, IL-17F, IL-22, IL-26, interferon-gamma, the chemokine CCL20 and transcription factor RORgammat. In situ, T(H)-17 cells were identified by expression of the IL-23 receptor and the memory T cell marker CD45RO. Psoriatic skin lesions contained IL-23-producing dendritic cells and were enriched in the cytokines produced by human T(H)-17 cells that promote the production of antimicrobial peptides in human keratinocytes. Our data collectively indicate that human and mouse T(H)-17 cells require distinct factors during differentiation and that human T(H)-17 cells may regulate innate immunity in epithelial cells.
Publisher: American Society of Hematology
Date: 09-2008
DOI: 10.1182/BLOOD-2008-02-142745
Abstract: The production of immunoglobulin E (IgE) is tightly regulated. This is evidenced by the fact that it comprises less than 0.0001% of serum Ig, and aberrant production causes atopic conditions, including allergy, rhinitis, and anaphylaxis. Interleukin-4 (IL-4) is a well-characterized inducer of IgE by human and murine B cells, whereas interferon-γ can antagonize this effect. IL-21 has also been recognized for its ability to suppress IL-4–induced IgE production by murine B cells. Here, we identified IL-21 as an inducer of IgE production by CD40L-stimulated human naive B cells. Furthermore, there was a striking synergy between IL-4 and IL-21 on inducing IgE secretion by CD40L-stimulated human B cells, such that the levels detected under these conditions exceeded those induced by IL-4 or IL-21 alone by more than 10-fold. IL-21 induced activation of STAT3 and analysis of B cells from patients with loss-of-function STAT3 mutations revealed that the ability of IL-21 to induce IgE secretion, and augment that driven by IL-4, was STAT3-dependent. These findings highlight a fundamental difference between the regulation of IgE production by human and murine B cells and have implications for the dysregulated production of IgE in conditions characterized by extremely high levels of serum IgE.
Publisher: Rockefeller University Press
Date: 17-10-2011
DOI: 10.1084/JEM.20110345
Abstract: In humans, DOCK8 immunodeficiency syndrome is characterized by severe cutaneous viral infections. Thus, CD8 T cell function may be compromised in the absence of DOCK8. In this study, by analyzing mutant mice and humans, we demonstrate a critical, intrinsic role for DOCK8 in peripheral CD8 T cell survival and function. DOCK8 mutation selectively diminished the abundance of circulating naive CD8 T cells in both species, and in DOCK8-deficient humans, most CD8 T cells displayed an exhausted CD45RA+CCR7− phenotype. Analyses in mice revealed the CD8 T cell abnormalities to be cell autonomous and primarily postthymic. DOCK8 mutant naive CD8 T cells had a shorter lifespan and, upon encounter with antigen on dendritic cells, exhibited poor LFA-1 synaptic polarization and a delay in the first cell ision. Although DOCK8 mutant T cells underwent near-normal primary clonal expansion after primary infection with recombinant influenza virus in vivo, they showed greatly reduced memory cell persistence and recall. These findings highlight a key role for DOCK8 in the survival and function of human and mouse CD8 T cells.
Publisher: Rockefeller University Press
Date: 22-11-2010
DOI: 10.1084/JEM.20100064
Abstract: Maturation and selection of high-affinity B cell clones in the germinal center (GC) relies on support from T follicular helper (TFH) cells. TFH cells are characterized by their localization to the B cell follicle and their high expression of the costimulatory molecules ICOS and PD1 and the cytokine IL-21, which promotes immunoglobulin (Ig) class switching and production by B cells. We show that the heterodimeric cytokine IL-27 is critical for the function of TFH cells and for normal and pathogenic GC responses. IL-27 signaling to T cells results in the production of IL-21, a known autocrine factor for the maintenance of TFH cells, in a STAT3-dependent manner. IL-27 also enhances the survival of activated CD4+ T cells and the expression of TFH cell phenotypic markers. In vivo, expression of the IL-27Rα chain is required to support IL-21 production and TFH cell survival in a T cell–intrinsic manner. The production of high-affinity antibodies is reduced, and pristane-elicited autoantibodies and glomerulonephritis are significantly diminished, in Il27ra−/− mice. Together, our data show a nonredundant role for IL-27 in the development of T cell–dependent antibody responses.
Publisher: American Society for Clinical Investigation
Date: 2012
DOI: 10.1172/JCI62949DS1
Publisher: Wiley
Date: 09-2009
DOI: 10.1038/ICB.2009.64
Abstract: T follicular helper (T(FH)) cells are a specialized subset of CD4(+) T cells that localize to B-cell follicles, where they are positioned to provide help for the induction of optimal humoral immune responses. Key features of T(FH) cells are the expressions of CXCR5, ICOS, interleukin (IL)-21 and BCL-6. The requirements for human T(FH) cell development are unknown. Here we show that IL-6, IL-12, IL-21 and IL-23 are capable of inducing IL-21 expression in naïve CD4(+) T cells isolated from human tonsils, peripheral blood and cord blood. However, only IL-12 induced sustained expressions of CXCR5 and ICOS on these activated naïve CD4(+) T cells, and endowed them with the ability to provide increased help to B cells for their differentiation into immunoglobulin-secreting cells. The effects of IL-12 were independent of interferon-gamma and T-bet, and associated with upregulation of BCL-6 expression. Thus, these cytokines, particularly IL-12, are likely to act at an early stage during dendritic cell-mediated priming of naïve CD4(+) T cells into a T(FH) cell fate, and thus underpin antibody-mediated immunity.
Publisher: Rockefeller University Press
Date: 23-06-2021
DOI: 10.1084/JEM.20202726
Abstract: We have described a child suffering from Mendelian susceptibility to mycobacterial disease (MSMD) due to autosomal recessive, complete T-bet deficiency, which impairs IFN-γ production by innate and innate-like adaptive, but not mycobacterial-reactive purely adaptive, lymphocytes. Here, we explore the persistent upper airway inflammation (UAI) and blood eosinophilia of this patient. Unlike wild-type (WT) T-bet, the mutant form of T-bet from this patient did not inhibit the production of Th2 cytokines, including IL-4, IL-5, IL-9, and IL-13, when overexpressed in T helper 2 (Th2) cells. Moreover, Herpesvirus saimiri–immortalized T cells from the patient produced abnormally large amounts of Th2 cytokines, and the patient had markedly high plasma IL-5 and IL-13 concentrations. Finally, the patient’s CD4+ αβ T cells produced most of the Th2 cytokines in response to chronic stimulation, regardless of their antigen specificities, a phenotype reversed by the expression of WT T-bet. T-bet deficiency thus underlies the excessive production of Th2 cytokines, particularly IL-5 and IL-13, by CD4+ αβ T cells, causing blood eosinophilia and UAI. The MSMD of this patient results from defective IFN-γ production by innate and innate-like adaptive lymphocytes, whereas the UAI and eosinophilia result from excessive Th2 cytokine production by adaptive CD4+ αβ T lymphocytes.
Publisher: The American Association of Immunologists
Date: 15-10-2016
Abstract: Germinal centers (GC) give rise to high-affinity and long-lived Abs and are critical in immunity and autoimmunity. IL-27 supports GCs by promoting survival and function of T follicular helper cells. We demonstrate that IL-27 also directly enhances GC B cell function. Exposure of naive human B cells to rIL-27 during in vitro activation enhanced their differentiation into CD20+CD38+CD27lowCD95+CD10+ cells, consistent with the surface marker phenotype of GC B cells. This effect was inhibited by loss-of-function mutations in STAT1 but not STAT3. To extend these findings, we studied the in vivo effects of IL-27 signals to B cells in the GC-driven Roquinsan/san lupus mouse model. Il27ra−/−Roquinsan/san mice exhibited significantly reduced GCs, IgG2a(c)+ autoantibodies, and nephritis. Mixed bone marrow chimeras confirmed that IL-27 acts through B cell– and CD4+ T cell–intrinsic mechanisms to support GCs and alter the production of pathogenic Ig isotypes. To our knowledge, our data provide the first evidence that IL-27 signals directly to B cells promote GCs and support the role of IL-27 in lupus.
Publisher: Oxford University Press (OUP)
Date: 19-04-2010
Abstract: Although inflammation is emerging as a candidate prostate cancer risk factor, the T-helper cytokine-rich [interleukins (IL)-5, 13 and 4] chromosomal region at 5q31.1 has been implicated in prostate cancer pathogenesis. In particular, IL-4 has been associated with prostate cancer progression, whereas the IL-4 -589C>T (rs2243250) promoter variant has been associated with differential gene expression. We genotyped rs2243250 and 11 tag single-nucleotide polymorphisms (SNPs) spanning 200 kb across the 5q31.1 region on 825 cases and 732 controls from the Risk Factors for Prostate Cancer Study. The minor alleles of rs2243250 and an IL-4 tagSNP rs2227284 were associated with a small increase in prostate cancer risk. Per allele odds ratios (ORs) are 1.32 [95% confidence interval (CI) 1.08-1.61, P = 0.006] and 1.26 (95% CI 1.07-1.48, P = 0.005), respectively. Although these associations were not replicated in an analysis of the Melbourne Collaborative Cohort Study, including 810 cases and 1733 controls, no clinicopathological characteristic was implicated for this ergence. Correlating rs2243250 genotypes to IL-4 gene transcript levels and circulating IL-4 plasma levels, we observe in contrast to previous reports, a non-significant trend toward the minor T-allele decreasing the likelihood of IL-4 activity. From our observed association between a low IL-4 producing promoter T-allele and prostate cancer risk, our study suggests an antitumor role for IL-4 in prostate cancer. Although we saw no association for IL-5 or IL-13 gene variants and prostate cancer risk, our findings call for further evaluation of IL-4 as a contributor to prostate cancer susceptibility.
Publisher: Elsevier BV
Date: 08-2013
Publisher: Rockefeller University Press
Date: 24-08-2015
DOI: 10.1084/JEM.20140280
Abstract: Autosomal recessive, complete TYK2 deficiency was previously described in a patient (P1) with intracellular bacterial and viral infections and features of hyper-IgE syndrome (HIES), including atopic dermatitis, high serum IgE levels, and staphylococcal abscesses. We identified seven other TYK2-deficient patients from five families and four different ethnic groups. These patients were homozygous for one of five null mutations, different from that seen in P1. They displayed mycobacterial and/or viral infections, but no HIES. All eight TYK2-deficient patients displayed impaired but not abolished cellular responses to (a) IL-12 and IFN-α/β, accounting for mycobacterial and viral infections, respectively (b) IL-23, with normal proportions of circulating IL-17+ T cells, accounting for their apparent lack of mucocutaneous candidiasis and (c) IL-10, with no overt clinical consequences, including a lack of inflammatory bowel disease. Cellular responses to IL-21, IL-27, IFN-γ, IL-28/29 (IFN-λ), and leukemia inhibitory factor (LIF) were normal. The leukocytes and fibroblasts of all seven newly identified TYK2-deficient patients, unlike those of P1, responded normally to IL-6, possibly accounting for the lack of HIES in these patients. The expression of exogenous wild-type TYK2 or the silencing of endogenous TYK2 did not rescue IL-6 hyporesponsiveness, suggesting that this phenotype was not a consequence of the TYK2 genotype. The core clinical phenotype of TYK2 deficiency is mycobacterial and/or viral infections, caused by impaired responses to IL-12 and IFN-α/β. Moreover, impaired IL-6 responses and HIES do not appear to be intrinsic features of TYK2 deficiency in humans.
Publisher: Elsevier BV
Date: 07-2009
DOI: 10.1016/J.IMMUNI.2009.06.009
Abstract: T follicular helper (Tfh) cells are crucial for generating humoral immune responses. In this issue of Immunity, Schmitt et al. (2009) reveal the differentiation of human Tfh cells is dependent on dendritic cell-derived interleukin-12.
Publisher: Rockefeller University Press
Date: 17-07-2018
DOI: 10.1084/JEM.20180010
Abstract: Gain-of-function (GOF) mutations in PIK3CD, encoding the p110δ subunit of phosphatidylinositide 3-kinase (PI3K), cause a primary immunodeficiency. Affected in iduals 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 in iduals with p110δ inhibitors.
Publisher: Rockefeller University Press
Date: 04-01-2010
DOI: 10.1084/JEM.20091706
Abstract: Engagement of cytokine receptors by specific ligands activate Janus kinase–signal transducer and activator of transcription (STAT) signaling pathways. The exact roles of STATs in human lymphocyte behavior remain incompletely defined. Interleukin (IL)-21 activates STAT1 and STAT3 and has emerged as a potent regulator of B cell differentiation. We have studied patients with inactivating mutations in STAT1 or STAT3 to dissect their contribution to B cell function in vivo and in response to IL-21 in vitro. STAT3 mutations dramatically reduced the number of functional, antigen (Ag)-specific memory B cells and abolished the ability of IL-21 to induce naive B cells to differentiate into plasma cells (PCs). This resulted from impaired activation of the molecular machinery required for PC generation. In contrast, STAT1 deficiency had no effect on memory B cell formation in vivo or IL-21–induced immunoglobulin secretion in vitro. Thus, STAT3 plays a critical role in generating effector B cells from naive precursors in humans. STAT3-activating cytokines such as IL-21 thus underpin Ag-specific humoral immune responses and provide a mechanism for the functional antibody deficit in STAT3-deficient patients.
Publisher: Wiley
Date: 19-11-2019
DOI: 10.1111/IMCB.12215
Abstract: Interleukin-9 (IL-9) producing CD4
Publisher: Springer Science and Business Media LLC
Date: 23-02-2018
DOI: 10.1038/S41598-018-21389-8
Abstract: A subset of human follicular helper T cells (TFH) cells expresses CD57 for which no distinct function has been identified. We show that CD57+ TFH cells are universally PD-1 hi , but compared to their CD57− PD-1 hi counterparts, express little IL-21 or IL-10 among others. Instead, CD57 expression on TFH cells marks cytotoxicity transcriptional signatures that translate into only a weak cytotoxic phenotype. Similarly, circulating PD-1+ CD57+ CD4+ T cells make less cytokine than their CD57− PD-1+ counterparts, but have a prominent cytotoxic phenotype. By analysis of responses to STAT3-dependent cytokines and cells from patients with gain- or loss-of-function STAT3 mutations, we show that CD4+ T cell cytotoxicity is STAT3-dependent. TFH formation also requires STAT3, but paradoxically, once formed, PD-1 hi cells become unresponsive to STAT3. These findings suggest that changes in blood and germinal center cytotoxicity might be affected by changes in STAT3 signaling, or modulation of PD-1 by therapy.
Publisher: Frontiers Media SA
Date: 04-09-2019
Publisher: American Association for the Advancement of Science (AAAS)
Date: 24-02-2023
DOI: 10.1126/SCIIMMUNOL.ABQ5204
Abstract: Patients with autosomal recessive (AR) IL-12p40 or IL-12Rβ1 deficiency display Mendelian susceptibility to mycobacterial disease (MSMD) due to impaired IFN-γ production and, less commonly, chronic mucocutaneous candidiasis (CMC) due to impaired IL-17A/F production. We report six patients from four kindreds with AR IL-23R deficiency. These patients are homozygous for one of four different loss-of-function IL23R variants. All six patients have a history of MSMD, but only two suffered from CMC. We show that IL-23 induces IL-17A only in MAIT cells, possibly contributing to the incomplete penetrance of CMC in patients unresponsive to IL-23. By contrast, IL-23 is required for both baseline and Mycobacterium -inducible IFN-γ immunity in both Vδ2 + γδ T and MAIT cells, probably contributing to the higher penetrance of MSMD in these patients. Human IL-23 appears to contribute to IL-17A/F–dependent immunity to Candida in a single lymphocyte subset but is required for IFN-γ–dependent immunity to Mycobacterium in at least two lymphocyte subsets.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 12-2014
Publisher: The American Association of Immunologists
Date: 15-05-2011
Abstract: High expression of CXCR5 is one of the defining hallmarks of T follicular helper cells (TFH), a CD4 Th cell subset that promotes germinal center reactions and the selection and affinity maturation of B cells. CXCR5 is also expressed on 20–25% of peripheral blood human central memory CD4 T cells (TCM), although the definitive function of these cells is not fully understood. The constitutive expression of CXCR5 on TFH cells and a fraction of circulating TCM suggests that CXCR5+ TCM may represent a specialized subset of memory-type TFH cells programmed for homing to follicles and providing B cell help. To verify this assumption, we analyzed this cell population and show its specialized function in supporting humoral immune responses. Compared with their CXCR5− TCM counterparts, CXCR5+ TCM expressed high levels of the chemokine CXCL13 and efficiently induced plasma cell differentiation and Ig secretion. We found that the distinct B cell helper qualities of CXCR5+ TCM were mainly due to high ICOS expression and pronounced responsiveness to ICOS ligand costimulation together with large IL-10 secretion. Furthermore, B cell helper attributes of CXCR5+ TCM were almost exclusively acquired on cognate interaction with B cells, but not with dendritic cells. This implies that a preferential recruitment of circulating CXCR5+ TCM to CXCL13-rich B cell follicles is required for the promotion of a quick and efficient protective secondary humoral immune response. Taken together, we propose that CXCR5+ TCM represent a distinct memory cell subset specialized in supporting Ab-mediated immune responses.
Publisher: Wiley
Date: 22-11-2011
DOI: 10.1111/J.1749-6632.2010.05824.X
Abstract: Effective B cell-mediated immunity, including the formation of germinal centers and the generation of high-affinity memory B cells and long-lived plasma cells, is dependent on CD4(+) T cells. Immunodeficiencies that present with defects in the antibody response have provided insights into the molecular mechanisms of B cell responses and the provision of T cell help. One such immunodeficiency is X-linked lymphoproliferative disease (XLP), which results from mutations in SH2D1A, the gene encoding SLAM-associated protein (SAP). Patients with XLP present with humoral defects characterized by hypogammaglobulinemia. We now know that SAP, through its signaling downstream of multiple members of the signaling lymphocytic activation molecule (SLAM) family of cell surface receptors, plays a crucial role in many aspects of this immune response. Here, we discuss the role of SAP in the generation of humoral immunity, particularly T cell-dependent antibody responses and the generation of germinal centers.
Publisher: American Society for Clinical Investigation
Date: 15-10-2013
DOI: 10.1172/JCI71927
Publisher: Frontiers Media SA
Date: 07-02-2018
Publisher: Elsevier BV
Date: 11-2012
DOI: 10.1016/J.JIM.2008.07.017
Abstract: Current methods for the detection and isolation of antigen-specific CD4(+) and CD8(+) T cells require the availability of peptide/MHC multimers or are restricted to cells that produce cytokines after antigen contact. Here we show that de novo cell surface expression of the TNF-receptor family member CD137 (4-1BB) identifies recently activated, but not resting, human CD4(+) and CD8(+) memory T cells. Maximum CD137 expression level is uniformly observed in both T-cell subsets at 24h after stimulation with antigen. In experiments with CMV and EBV-reactive T cells, we confirmed the specificity of CD137 expression by co-staining with peptide/HLA tetramers. Substantial proportions of CD137(+) T cells did not produce IFN-gamma, suggesting that CD137 detects a broader repertoire of antigen-specific T cells. Activated CD137(+) T cells could be easily purified by MACS and expanded in vitro thereafter. This CD137-based enrichment method was capable of isolating 2-fold higher numbers of anti-viral CD4(+) and CD8(+) T cells compared to the IFN-gamma secretion assay. In conclusion, antigen-triggered CD137 expression allows the rapid detection and sorting of virus-reactive CD4(+) and CD8(+) T cells. The CD137 assay is most attractive for the simultaneous targeting of anti-viral T helper and effector cells in monitoring studies and adoptive immunotherapy trials.
Publisher: Rockefeller University Press
Date: 04-05-2015
DOI: 10.1084/JEM.20141992
Abstract: Unconventional T cells such as γδ T cells, natural killer T cells (NKT cells) and mucosal-associated invariant T cells (MAIT cells) are a major component of the immune system however, the cytokine signaling pathways that control their development and function in humans are unknown. Primary immunodeficiencies caused by single gene mutations provide a unique opportunity to investigate the role of specific molecules in regulating human lymphocyte development and function. We found that in iduals with loss-of-function mutations in STAT3 had reduced numbers of peripheral blood MAIT and NKT but not γδ T cells. Analysis of STAT3 mosaic in iduals revealed that this effect was cell intrinsic. Surprisingly, the residual STAT3-deficient MAIT cells expressed normal levels of the transcription factor RORγt. Despite this, they displayed a deficiency in secretion of IL-17A and IL-17F, but were able to secrete normal levels of cytokines such as IFNγ and TNF. The deficiency in MAIT and NKT cells in STAT3-deficient patients was mirrored by loss-of-function mutations in IL12RB1 and IL21R, respectively. Thus, these results reveal for the first time the essential role of STAT3 signaling downstream of IL-23R and IL-21R in controlling human MAIT and NKT cell numbers.
Publisher: Springer Science and Business Media LLC
Date: 24-08-2016
DOI: 10.1038/NATURE19428
Publisher: Elsevier BV
Date: 06-2014
DOI: 10.1016/J.COI.2014.01.015
Abstract: Signalling in lymphocytes through cytokine receptors is critical for their development, activation and differentiation into effector cells that mediate protection against pathogens and provide the host with protective immunological memory. The essential role of cytokine signalling has been established not only by the generation and examination of gene-targeted mice, but also 'Experiments of Nature' whereby monogenic mutations cause primary immunodeficient conditions characterised by impaired immunity to infectious diseases due to compromised lymphocyte function. Mutations in STAT3 cause autosomal dominant hyper-IgE syndrome. Here, we will review how the study of STAT3-deficient in iduals has revealed non-redundant functions of STAT3 and specific cytokines in human lymphocyte biology, and have delineated mechanisms underlying the distinct clinical features of autosomal dominant hyper-IgE syndrome.
Publisher: Rockefeller University Press
Date: 29-07-2013
DOI: 10.1084/JEM.20130592
Abstract: Kaposi sarcoma (KS), a human herpes virus 8 (HHV-8 also called KSHV)–induced endothelial tumor, develops only in a small fraction of in iduals infected with HHV-8. We hypothesized that inborn errors of immunity to HHV-8 might underlie the exceedingly rare development of classic KS in childhood. We report here autosomal recessive OX40 deficiency in an otherwise healthy adult with childhood-onset classic KS. OX40 is a co-stimulatory receptor expressed on activated T cells. Its ligand, OX40L, is expressed on various cell types, including endothelial cells. We found OX40L was abundantly expressed in KS lesions. The mutant OX40 protein was poorly expressed on the cell surface and failed to bind OX40L, resulting in complete functional OX40 deficiency. The patient had a low proportion of effector memory CD4+ T cells in the peripheral blood, consistent with impaired CD4+ T cell responses to recall antigens in vitro. The proportion of effector memory CD8+ T cells was less diminished. The proportion of circulating memory B cells was low, but the antibody response in vivo was intact, including the response to a vaccine boost. Together, these findings suggest that human OX40 is necessary for robust CD4+ T cell memory and confers apparently selective protective immunity against HHV-8 infection in endothelial cells.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 04-07-0004
DOI: 10.1126/SCIIMMUNOL.ABQ3277
Abstract: High-level expression of the transcription factor T-bet characterizes a phenotypically distinct murine B cell population known as “age-associated B cells” (ABCs). T-bet–deficient mice have reduced ABCs and impaired humoral immunity. We describe a patient with inherited T-bet deficiency and largely normal humoral immunity including intact somatic hypermutation, affinity maturation and memory B cell formation in vivo, and B cell differentiation into Ig-producing plasmablasts in vitro. Nevertheless, the patient exhibited skewed class switching to IgG1, IgG4, and IgE, along with reduced IgG2, both in vivo and in vitro. Moreover, T-bet was required for the in vivo and in vitro development of a distinct subset of human B cells characterized by reduced expression of CD21 and the concomitantly high expression of CD19, CD20, CD11c, FCRL5, and T-bet, a phenotype that shares many features with murine ABCs. Mechanistically, human T-bet governed CD21 lo CD11c hi B cell differentiation by controlling the chromatin accessibility of lineage-defining genes in these cells: FAS , IL21R , SEC61B , DUSP4 , DAPP1 , SOX5 , CD79B , and CXCR4 . Thus, human T-bet is largely redundant for long-lived protective humoral immunity but is essential for the development of a distinct subset of human CD11c hi CD21 lo B cells.
Publisher: Springer Science and Business Media LLC
Date: 27-11-2012
DOI: 10.1038/NI.2166
Abstract: Lipid antigens trigger help from natural killer T cells (NKT cells) for B cells, and direct conjugation of lipid agonists to antigen profoundly augments antibody responses. Here we show that in vivo, NKT cells engaged in stable and prolonged cognate interactions with B cells and induced the formation of early germinal centers. Mouse and human NKT cells formed CXCR5(+)PD-1(hi) follicular helper NKT cells (NKT(FH) cells), and this process required expression of the transcriptional repressor Bcl-6, signaling via the coreceptor CD28 and interaction with B cells. NKT(FH) cells provided direct cognate help to antigen-specific B cells that was dependent on interleukin 21 (IL-21). Unlike T cell-dependent germinal centers, those driven by NKT(FH) cells did not generate long-lived plasma cells. Our results demonstrate the existence of a Bcl-6-dependent subset of NKT cells specialized in providing help to B cells.
No related grants have been discovered for Cindy Ma.