Publications by authors named "Carola G Vinuesa"

101 Publications

Increased burden of rare variants in genes of the endosomal Toll-like receptor pathway in patients with systemic lupus erythematosus.

Lupus 2021 Jul 16:9612033211033979. Epub 2021 Jul 16.

Department of Immunology and Infectious Disease, John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia.

Objective: To compare the frequency of rare variants in genes of the pathophysiologically relevant endosomal Toll-like receptor (eTLR) pathway and any quantifiable differences in variant rarity, predicted deleteriousness, or molecular proximity in patients with systemic lupus erythematosus (SLE) and healthy controls.

Patients And Methods: 65 genes associated with the eTLR pathway were identified by literature search and pathway analysis. Using next generation sequencing techniques, these were compared in two randomised cohorts of patients with SLE (n = 114 and n = 113) with 197 healthy controls. Genetically determined ethnicity was used to normalise minor allele frequencies (MAF) for the identified genetic variants and these were then compared by their frequency: rare (MAF < 0.005), uncommon (MAF 0.005-0.02), and common (MAF >0.02). This was compared to the results for 65 randomly selected genes.

Results: Patients with SLE are more likely to carry a rare nonsynonymous variant affecting proteins within the eTLR pathway than healthy controls. Furthermore, individuals with SLE are more likely to have multiple rare variants in this pathway. There were no differences in rarity, Combined Annotation Dependent Depletion (CADD) score, or molecular proximity for rare eTLR pathway variants.

Conclusions: Rare non-synonymous variants are enriched in patients with SLE in the eTLR pathway. This supports the hypothesis that SLE arises from several rare variants of relatively large effect rather than many common variants of small effect.
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http://dx.doi.org/10.1177/09612033211033979DOI Listing
July 2021

CD4 T cells that help B cells - a proposal for uniform nomenclature.

Trends Immunol 2021 08 6;42(8):658-669. Epub 2021 Jul 6.

Lymphocyte Signalling and Development, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK.

T follicular helper (Tfh) cells cognately guide differentiation of antigen-primed B cells in secondary lymphoid tissues. 'Tfh-like' populations not expressing the canonical Tfh cell transcription factor BCL6 have also been described, which can aid particular aspects of B cell differentiation. Tfh and Tfh-like cells are essential for protective and pathological humoral immunity. These CD4 T cells that help B cells are polarized to produce diverse combinations of cytokines and chemokine receptors and can be grouped into distinct subsets that promote antibodies of different isotype, affinity, and duration, according to the nature of immune challenge. However, unified nomenclature to describe the distinct functional Tfh and Tfh-like cells does not exist. While explicitly acknowledging cellular plasticity, we propose categorizing these cell states into three groups based on phenotype and function, paired with their anatomical site of action.
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http://dx.doi.org/10.1016/j.it.2021.06.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8324560PMC
August 2021

Sequence-dependent inhibition of cGAS and TLR9 DNA sensing by 2'-O-methyl gapmer oligonucleotides.

Nucleic Acids Res 2021 06;49(11):6082-6099

Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria 3168, Australia.

Oligonucleotide-based therapeutics have the capacity to engage with nucleic acid immune sensors to activate or block their response, but a detailed understanding of these immunomodulatory effects is currently lacking. We recently showed that 2'-O-methyl (2'OMe) gapmer antisense oligonucleotides (ASOs) exhibited sequence-dependent inhibition of sensing by the RNA sensor Toll-Like Receptor (TLR) 7. Here we discovered that 2'OMe ASOs can also display sequence-dependent inhibitory effects on two major sensors of DNA, namely cyclic GMP-AMP synthase (cGAS) and TLR9. Through a screen of 80 2'OMe ASOs and sequence mutants, we characterized key features within the 20-mer ASOs regulating cGAS and TLR9 inhibition, and identified a highly potent cGAS inhibitor. Importantly, we show that the features of ASOs inhibiting TLR9 differ from those inhibiting cGAS, with only a few sequences inhibiting both pathways. Together with our previous studies, our work reveals a complex pattern of immunomodulation where 95% of the ASOs tested inhibited at least one of TLR7, TLR9 or cGAS by ≥30%, which may confound interpretation of their in vivo functions. Our studies constitute the broadest analysis of the immunomodulatory effect of 2'OMe ASOs on nucleic acid sensing to date and will support refinement of their therapeutic development.
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http://dx.doi.org/10.1093/nar/gkab451DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8216285PMC
June 2021

Follicular regulatory T cells produce neuritin to regulate B cells.

Cell 2021 04 11;184(7):1775-1789.e19. Epub 2021 Mar 11.

Dept of Immunology and Infectious Disease, The John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia. Electronic address:

Regulatory T cells prevent the emergence of autoantibodies and excessive IgE, but the precise mechanisms are unclear. Here, we show that BCL6-expressing Tregs, known as follicular regulatory T (Tfr) cells, produce abundant neuritin protein that targets B cells. Mice lacking Tfr cells or neuritin in Foxp3-expressing cells accumulated early plasma cells in germinal centers (GCs) and developed autoantibodies against histones and tissue-specific self-antigens. Upon immunization, these mice also produced increased plasma IgE and IgG1. We show that neuritin is taken up by B cells, causes phosphorylation of numerous proteins, and dampens IgE class switching. Neuritin reduced differentiation of mouse and human GC B cells into plasma cells, downregulated BLIMP-1, and upregulated BCL6. Administration of neuritin to Tfr-deficient mice prevented the accumulation of early plasma cells in GCs. Production of neuritin by Tfr cells emerges as a central mechanism to suppress B cell-driven autoimmunity and IgE-mediated allergies.
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http://dx.doi.org/10.1016/j.cell.2021.02.027DOI Listing
April 2021

Infanticide vs. inherited cardiac arrhythmias.

Europace 2021 03;23(3):441-450

Istituto Auxologico Italiano, IRCCS, Center for Cardiac Arrhythmias of Genetic Origin, Via Pier Lombardo, 22, 20135 Milan, Italy.

Aims: In 2003, an Australian woman was convicted by a jury of smothering and killing her four children over a 10-year period. Each child died suddenly and unexpectedly during a sleep period, at ages ranging from 19 days to 18 months. In 2019 we were asked to investigate if a genetic cause could explain the children's deaths as part of an inquiry into the mother's convictions.

Methods And Results: Whole genomes or exomes of the mother and her four children were sequenced. Functional analysis of a novel CALM2 variant was performed by measuring Ca2+-binding affinity, interaction with calcium channels and channel function. We found two children had a novel calmodulin variant (CALM2 G114R) that was inherited maternally. Three genes (CALM1-3) encode identical calmodulin proteins. A variant in the corresponding residue of CALM3 (G114W) was recently reported in a child who died suddenly at age 4 and a sibling who suffered a cardiac arrest at age 5. We show that CALM2 G114R impairs calmodulin's ability to bind calcium and regulate two pivotal calcium channels (CaV1.2 and RyR2) involved in cardiac excitation contraction coupling. The deleterious effects of G114R are similar to those produced by G114W and N98S, which are considered arrhythmogenic and cause sudden cardiac death in children.

Conclusion: A novel functional calmodulin variant (G114R) predicted to cause idiopathic ventricular fibrillation, catecholaminergic polymorphic ventricular tachycardia, or mild long QT syndrome was present in two children. A fatal arrhythmic event may have been triggered by their intercurrent infections. Thus, calmodulinopathy emerges as a reasonable explanation for a natural cause of their deaths.
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http://dx.doi.org/10.1093/europace/euaa272DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7947592PMC
March 2021

Nfkb2 variants reveal a p100-degradation threshold that defines autoimmune susceptibility.

J Exp Med 2021 02;218(2)

Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia.

NF-κB2/p100 (p100) is an inhibitor of κB (IκB) protein that is partially degraded to produce the NF-κB2/p52 (p52) transcription factor. Heterozygous NFKB2 mutations cause a human syndrome of immunodeficiency and autoimmunity, but whether autoimmunity arises from insufficiency of p52 or IκB function of mutated p100 is unclear. Here, we studied mice bearing mutations in the p100 degron, a domain that harbors most of the clinically recognized mutations and is required for signal-dependent p100 degradation. Distinct mutations caused graded increases in p100-degradation resistance. Severe p100-degradation resistance, due to inheritance of one highly degradation-resistant allele or two subclinical alleles, caused thymic medullary hypoplasia and autoimmune disease, whereas the absence of p100 and p52 did not. We inferred a similar mechanism occurs in humans, as the T cell receptor repertoires of affected humans and mice contained a hydrophobic signature of increased self-reactivity. Autoimmunity in autosomal dominant NFKB2 syndrome arises largely from defects in nonhematopoietic cells caused by the IκB function of degradation-resistant p100.
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http://dx.doi.org/10.1084/jem.20200476DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7595743PMC
February 2021

A Dual-Antigen Enzyme-Linked Immunosorbent Assay Allows the Assessment of Severe Acute Respiratory Syndrome Coronavirus 2 Antibody Seroprevalence in a Low-Transmission Setting.

J Infect Dis 2021 01;223(1):10-14

Department of Immunology and Infectious Disease, John Curtin School of Medical Research, The Australian National University, Canberra, Australia.

Estimates of seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies have been hampered by inadequate assay sensitivity and specificity. Using an enzyme-linked immunosorbent assay-based approach that combines data about immunoglobulin G responses to both the nucleocapsid and spike receptor binding domain antigens, we show that excellent sensitivity and specificity can be achieved. We used this assay to assess the frequency of virus-specific antibodies in a cohort of elective surgery patients in Australia and estimated seroprevalence in Australia to be 0.28% (95% Confidence Interval, 0-1.15%). These data confirm the low level of transmission of SARS-CoV-2 in Australia before July 2020 and validate the specificity of our assay.
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http://dx.doi.org/10.1093/infdis/jiaa623DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7665523PMC
January 2021

COVID-19 Makes B Cells Forget, but T Cells Remember.

Cell 2020 10 4;183(1):13-15. Epub 2020 Sep 4.

Department of Immunology and Infectious Disease, John Curtin School of Medical Research, Australian National University, 131 Garran Road, Acton, 2601 ACT, Australia; China Australia Centre for Personalised Immunology (CACPI), Renji Hospital, School of Medicine, Shanghai Jiao Tong University (SJTUSM), Shanghai, 200001, China. Electronic address:

Understanding which arms of the immune response are responsible for protection against SARS-CoV-2 infection is key to predicting long-term immunity and to inform vaccine design. Two studies in this issue of Cell collectively suggest that, although SARS-CoV-2 infection may blunt long-lived antibody responses, immune memory might still be achieved through virus-specific memory T cells.
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http://dx.doi.org/10.1016/j.cell.2020.09.013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7472965PMC
October 2020

Equitable Expanded Carrier Screening Needs Indigenous Clinical and Population Genomic Data.

Am J Hum Genet 2020 08;107(2):175-182

National Centre for Indigenous Genomics, Australian National University, Canberra, ACT 2600, Australia; John Curtin School of Medical Research, Australian National University, Canberra, ACT 2600, Australia.

Expanded carrier screening (ECS) for recessive monogenic diseases requires prior knowledge of genomic variation, including DNA variants that cause disease. The composition of pathogenic variants differs greatly among human populations, but historically, research about monogenic diseases has focused mainly on people with European ancestry. By comparison, less is known about pathogenic DNA variants in people from other parts of the world. Consequently, inclusion of currently underrepresented Indigenous and other minority population groups in genomic research is essential to enable equitable outcomes in ECS and other areas of genomic medicine. Here, we discuss this issue in relation to the implementation of ECS in Australia, which is currently being evaluated as part of the national Government's Genomics Health Futures Mission. We argue that significant effort is required to build an evidence base and genomic reference data so that ECS can bring significant clinical benefit for many Aboriginal and/or Torres Strait Islander Australians. These efforts are essential steps to achieving the Australian Government's objectives and its commitment "to leveraging the benefits of genomics in the health system for all Australians." They require culturally safe, community-led research and community involvement embedded within national health and medical genomics programs to ensure that new knowledge is integrated into medicine and health services in ways that address the specific and articulated cultural and health needs of Indigenous people. Until this occurs, people who do not have European ancestry are at risk of being, in relative terms, further disadvantaged.
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http://dx.doi.org/10.1016/j.ajhg.2020.06.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7413856PMC
August 2020

A missense mutation in the MLKL brace region promotes lethal neonatal inflammation and hematopoietic dysfunction.

Nat Commun 2020 06 19;11(1):3150. Epub 2020 Jun 19.

The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, 3052, Australia.

MLKL is the essential effector of necroptosis, a form of programmed lytic cell death. We have isolated a mouse strain with a single missense mutation, Mlkl, that alters the two-helix 'brace' that connects the killer four-helix bundle and regulatory pseudokinase domains. This confers constitutive, RIPK3 independent killing activity to MLKL. Homozygous mutant mice develop lethal postnatal inflammation of the salivary glands and mediastinum. The normal embryonic development of Mlkl homozygotes until birth, and the absence of any overt phenotype in heterozygotes provides important in vivo precedent for the capacity of cells to clear activated MLKL. These observations offer an important insight into the potential disease-modulating roles of three common human MLKL polymorphisms that encode amino acid substitutions within or adjacent to the brace region. Compound heterozygosity of these variants is found at up to 12-fold the expected frequency in patients that suffer from a pediatric autoinflammatory disease, chronic recurrent multifocal osteomyelitis (CRMO).
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http://dx.doi.org/10.1038/s41467-020-16819-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7305203PMC
June 2020

Rare genetic variants in systemic autoimmunity.

Immunol Cell Biol 2020 07 16;98(6):490-499. Epub 2020 May 16.

Centre for Personalised Immunology, NHMRC Centre for Research Excellence, Acton, ACT, 2601, Australia.

Autoimmune disease is a substantial cause of morbidity and is strongly influenced by genetic risk. Extensive efforts have characterized the overall genetic basis of many autoimmune diseases, typically by investigation of common variants. While these common variants have modest effects and may cumulatively predispose to disease, it is also increasingly apparent that rare variants have significantly greater effect on phenotype and are likely to contribute to autoimmune disease. Recent advances have illustrated the next fundamental step in elucidating the genetic basis of autoimmunity, moving beyond association to demonstrate the functional consequences of these variants.
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http://dx.doi.org/10.1111/imcb.12339DOI Listing
July 2020

Non-parametric Heat Map Representation of Flow Cytometry Data: Identifying Cellular Changes Associated With Genetic Immunodeficiency Disorders.

Front Immunol 2019 11;10:2134. Epub 2019 Sep 11.

Department of Immunology and Infectious Diseases, Australian National University, Canberra, ACT, Australia.

Genetic primary immunodeficiency diseases are increasingly recognized, with pathogenic mutations changing the composition of circulating leukocyte subsets measured by flow cytometry (FCM). Discerning changes in multiple subpopulations is challenging, and subtle trends might be missed if traditional reference ranges derived from a control population are applied. We developed an algorithm where centiles were allocated using non-parametric comparison to controls, generating multiparameter heat maps to simultaneously represent all leukocyte subpopulations for inspection of trends within a cohort or segregation with a putative genetic mutation. To illustrate this method, we analyzed patients with Primary Antibody Deficiency (PAD) and kindreds harboring mutations in (encoding TACI), , and . In PAD, loss of switched memory B cells (B-SM) was readily demonstrated, but as a continuous, not dichotomous, variable. Expansion of CXCR5+/CD45RA- CD4+ T cells (X5-Th cells) was a prominent feature in PAD, particularly in TACI mutants, and patients with expansion in CD21-lo B cells or transitional B cells were readily apparent. We observed differences between unaffected and affected TACI mutants (increased B cells and CD8+ T-effector memory cells, loss of B-SM cells and non-classical monocytes), cellular signatures that distinguished haploinsufficiency itself (expansion of plasmablasts, activated CD4+ T cells, regulatory T cells, and X5-Th cells) from its clinical expression (B-cell depletion), and those that were associated with gain-of-function mutation (decreased CD8+ T effector memory cells, B cells, CD21-lo B cells, B-SM cells, and NK cells). Co-efficients of variation exceeded 30% for 36/54 FCM parameters, but by comparing inter-assay variation with disease-related variation, we ranked each parameter in terms of laboratory precision vs. disease variability, identifying X5-Th cells (and derivatives), naïve, activated, and central memory CD8+ T cells, transitional B cells, memory and SM-B cells, plasmablasts, activated CD4 cells, and total T cells as the 10 most useful cellular parameters. Applying these to cluster analysis of our PAD cohort, we could detect subgroups with the potential to reflect underlying genotypes. Heat mapping of normalized FCM data reveals cellular trends missed by standard reference ranges, identifies changes associating with a phenotype or genotype, and could inform hypotheses regarding pathogenesis of genetic immunodeficiency.
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http://dx.doi.org/10.3389/fimmu.2019.02134DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6749093PMC
October 2020

Class-Switch Recombination Occurs Infrequently in Germinal Centers.

Immunity 2019 08 30;51(2):337-350.e7. Epub 2019 Jul 30.

Department of Immunology and Infectious Disease and Centre for Personalised Immunology, The John Curtin School of Medical Research, The Australian National University, Canberra ACT 0200, Australia; China-Australia Centre for Personalised Immunology, Department of Rheumatology, Shanghai Renji Hospital, Shanghai JiaoTong University, Shanghai, China. Electronic address:

Class-switch recombination (CSR) is a DNA recombination process that replaces the immunoglobulin (Ig) constant region for the isotype that can best protect against the pathogen. Dysregulation of CSR can cause self-reactive BCRs and B cell lymphomas; understanding the timing and location of CSR is therefore important. Although CSR commences upon T cell priming, it is generally considered a hallmark of germinal centers (GCs). Here, we have used multiple approaches to show that CSR is triggered prior to differentiation into GC B cells or plasmablasts and is greatly diminished in GCs. Despite finding a small percentage of GC B cells expressing germline transcripts, phylogenetic trees of GC BCRs from secondary lymphoid organs revealed that the vast majority of CSR events occurred prior to the onset of somatic hypermutation. As such, we have demonstrated the existence of IgM-dominated GCs, which are unlikely to occur under the assumption of ongoing switching.
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http://dx.doi.org/10.1016/j.immuni.2019.07.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6914312PMC
August 2019

Genomic test ends a long diagnostic odyssey in a patient with resistance to thyroid hormones.

Thyroid Res 2019 15;12. Epub 2019 Jul 15.

Institute of Pathophysiology and Nuclear Medicine, University Clinical Hospital, Skopje, Macedonia.

Background: Resistance to thyroid hormones is a very rare condition, which is often misdiagnosed and mistreated. The cases where there is a concomitant autoimmune thyroid disorder are ultra-rare and particularly challenging to treat. Diagnostic and research-based genomic testing can sometimes identify pathogenic variants unrelated to the primary reason for testing (incidental findings).

Case Presentation: We present a patient with thyroid resistance associated with hypothyroid Hashimoto thyroiditis. The long diagnostic odyssey spanning over 20-years included repeated misdiagnoses and mistreatments and was concluded by a research-based genomic testing, identifying a "de novo" pathogenic variant. The varying sensitivity of various tissues to thyroid hormones accompanied by hypothyroid Hashimoto thyroiditis continues to pose a significant treatment challenge.

Conclusions: Thyroid hormone resistance continues to be an un(der)- and misdiagnosed thyroid condition whose management is particularly challenging when associated with autoimmune thyroid disease. Whole exome sequencing has the potential to identify pathogenic variants as incidental findings. Reporting such secondary findings from genomic testing may be particularly important in the context of the rarity of the condition and the potential clinical consequences of misdiagnosis and mistreatment.
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http://dx.doi.org/10.1186/s13044-019-0068-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6631449PMC
July 2019

Regulatory roles of IL-10-producing human follicular T cells.

J Exp Med 2019 08 17;216(8):1843-1856. Epub 2019 Jun 17.

Department of Immunology and Infectious Disease and Centre for Personalised Immunology, The John Curtin School of Medical Research, The Australian National University, Canberra, Australia

Mucosal lymphoid tissues such as human tonsil are colonized by bacteria and exposed to ingested and inhaled antigens, requiring tight regulation of immune responses. Antibody responses are regulated by follicular helper T (T) cells and FOXP3 follicular regulatory T (T) cells. Here we describe a subset of human tonsillar follicular T cells identified by expression of T markers and CD25 that are the main source of follicular T (T) cell-derived IL-10. Despite lack of FOXP3 expression, CD25 T cells resemble T reg cells in high CTLA4 expression, low IL-2 production, and their ability to repress T cell proliferation. CD25 T cell-derived IL-10 dampens induction of B cell class-switching to IgE. In children, circulating total IgE titers were inversely correlated with the frequencies of tonsil CD25 T cells and IL-10-producing T cells but not with total T reg cells, T, or IL-10-producing T cells. Thus, CD25 T cells emerge as a subset with unique T and B cell regulatory activities that may help prevent atopy.
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http://dx.doi.org/10.1084/jem.20190493DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6683995PMC
August 2019

Functional rare and low frequency variants in BLK and BANK1 contribute to human lupus.

Nat Commun 2019 05 17;10(1):2201. Epub 2019 May 17.

Department of Immunology, The Canberra Hospital, Garran, 2601, ACT, Australia.

Systemic lupus erythematosus (SLE) is the prototypic systemic autoimmune disease. It is thought that many common variant gene loci of weak effect act additively to predispose to common autoimmune diseases, while the contribution of rare variants remains unclear. Here we describe that rare coding variants in lupus-risk genes are present in most SLE patients and healthy controls. We demonstrate the functional consequences of rare and low frequency missense variants in the interacting proteins BLK and BANK1, which are present alone, or in combination, in a substantial proportion of lupus patients. The rare variants found in patients, but not those found exclusively in controls, impair suppression of IRF5 and type-I IFN in human B cell lines and increase pathogenic lymphocytes in lupus-prone mice. Thus, rare gene variants are common in SLE and likely contribute to genetic risk.
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http://dx.doi.org/10.1038/s41467-019-10242-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6525203PMC
May 2019

Gain-of-function mutation causes human combined immune deficiency.

J Exp Med 2018 11 18;215(11):2715-2724. Epub 2018 Oct 18.

Centre for Personalised Immunology, Australian National University, Canberra, Australia

Genetic mutations account for many devastating early onset immune deficiencies. In contrast, less severe and later onset immune diseases, including in patients with no prior family history, remain poorly understood. Whole exome sequencing in two cohorts of such patients identified a novel heterozygous de novo missense mutation (c.607G>A) in two separate kindreds in whom probands presented with immune dysregulation, combined T and B cell deficiency, inflammation, and epithelial defects. encodes IKK2, which activates NF-κB signaling. IKK2 results in enhanced NF-κB signaling, as well as T and B cell functional defects. IKK2 is a highly conserved residue, and to prove causation, we generated an accurate mouse model by introducing the precise orthologous codon change in using CRISPR/Cas9. Mice and humans carrying this missense mutation exhibit remarkably similar cellular and biochemical phenotypes. Accurate mouse models engineered by CRISPR/Cas9 can help characterize novel syndromes arising from de novo germline mutations and yield insight into pathogenesis.
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http://dx.doi.org/10.1084/jem.20180639DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6219745PMC
November 2018

Systemic lupus erythematosus: A new autoimmune disorder in Kabuki syndrome.

Eur J Med Genet 2019 Jun 11;62(6):103538. Epub 2018 Sep 11.

Department of Paediatrics, Division of Rheumatology and Immunology, University Hospital Centre Zagreb, University of Zagreb School of Medicine, Zagreb, Croatia. Electronic address:

We report a case of a 17-year-old Caucasian girl with syndromic features of clinically unrecognized Kabuki syndrome (KS), who developed systemic lupus erythematosus (SLE). Diagnosis of KS was established after whole exome sequencing (WES) and detection of de novo frameshift 1bp deletion in histone-lysine N-methyltransferase 2D gene (KMT2D). The pathogenic variant in exon 34 (c.8626delC: 55 reads C, 56 reads delC), has not been described previously and is predicted to truncate the protein (p.Gln2876Serfs*34) resulting in KMT2D loss of function. Notwithstanding that patients with KS have a substantial susceptibility to various autoimmune diseases, to the best of our knowledge this is the first report of an SLE and KS association. The exact relationship between the two conditions in our patient is difficult to determine with certainty, as a number of clinical features, including positive antiphospholipid antibodies, persistent hypogammaglobulinemia and the episode of convulsions may occur in both conditions, suggesting potential overlap of KS and SLE. The combination of a high susceptibility towards infections and an autoimmune disorder present a great challenge when trying to achieve the optimum therapy which will enable the patient to stay on the thin line of remission. This case report emphasizes the value of WES as a powerful tool for the diagnosis of rare disorders and/or unusual disease presentations of possible genetic cause.
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http://dx.doi.org/10.1016/j.ejmg.2018.09.005DOI Listing
June 2019

Synaptic Interactions in Germinal Centers.

Front Immunol 2018 13;9:1858. Epub 2018 Aug 13.

John Curtin School of Medical Research, Australian National University, Acton, ACT, Australia.

The germinal center (GC) is a complex, highly dynamic microanatomical niche that allows the generation of high-affinity antibody-producing plasma cells and memory B cells. These cells constitute the basis of long-lived highly protective antibody responses. For affinity maturation to occur, B cells undergo multiple rounds of proliferation and mutation of the genes that encode the immunoglobulin V region followed by selection by specialized T cells called follicular helper T (T) cells. In order to achieve this result, the GC requires spatially and temporally coordinated interactions between the different cell types, including B and T lymphocytes and follicular dendritic cells. Cognate interactions between T and GC B cells resemble cellular connections and synaptic communication within the nervous system, which allow signals to be transduced rapidly and effectively across the synaptic cleft. Such immunological synapses are particularly critical in the GC where the speed of T-B cell interactions is faster and their duration shorter than at other sites. In addition, the antigen-based specificity of cognate interactions in GCs is critical for affinity-based selection in which B cells compete for T cell help so that rapid modulation of the signaling threshold determines the outcome of the interaction. In the context of GCs, which contain large numbers of cells in a highly compacted structure, focused delivery of signals across the interacting cells becomes particularly important. Promiscuous or bystander delivery of positive selection signals could potentially lead to the appearance of long-lived self-reactive B cell clones. Cytokines, cytotoxic granules, and more recently neurotransmitters have been shown to be transferred from T to B cells upon cognate interactions. This review describes the current knowledge on immunological synapses occurring during GC responses including the type of granules, their content, and function in T-mediated help to B cells.
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http://dx.doi.org/10.3389/fimmu.2018.01858DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6099157PMC
September 2019

STAT3 regulates cytotoxicity of human CD57+ CD4+ T cells in blood and lymphoid follicles.

Sci Rep 2018 02 23;8(1):3529. Epub 2018 Feb 23.

Department of Immunology and Infectious Disease, John Curtin School of Medical Research, Australian National University, ACT, 2601, Australia.

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, but compared to their CD57- PD-1 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 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.
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http://dx.doi.org/10.1038/s41598-018-21389-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5824848PMC
February 2018

Atypical chemokine receptor 4 shapes activated B cell fate.

J Exp Med 2018 03 31;215(3):801-813. Epub 2018 Jan 31.

Department of Molecular and Cellular Biology, School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia

Activated B cells can initially differentiate into three functionally distinct fates-early plasmablasts (PBs), germinal center (GC) B cells, or early memory B cells-by mechanisms that remain poorly understood. Here, we identify atypical chemokine receptor 4 (ACKR4), a decoy receptor that binds and degrades CCR7 ligands CCL19/CCL21, as a regulator of early activated B cell differentiation. By restricting initial access to splenic interfollicular zones (IFZs), ACKR4 limits the early proliferation of activated B cells, reducing the numbers available for subsequent differentiation. Consequently, ACKR4 deficiency enhanced early PB and GC B cell responses in a CCL19/CCL21-dependent and B cell-intrinsic manner. Conversely, aberrant localization of ACKR4-deficient activated B cells to the IFZ was associated with their preferential commitment to the early PB linage. Our results reveal a regulatory mechanism of B cell trafficking via an atypical chemokine receptor that shapes activated B cell fate.
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http://dx.doi.org/10.1084/jem.20171067DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5839757PMC
March 2018

HIV Immunogens: Affinity Is Key.

Immunity 2018 01;48(1):11-13

Department of Immunology and Infectious Disease, The John Curtin School of Medical Research, Australian National University, Canberra, Australia. Electronic address:

Generation of broadly neutralizing antibodies is a key aim of HIV vaccine design, but the precursor B cells are rare. Abbott et al. (2018) report that high affinity and avidity immunogens are required to promote maturation of low frequency B cells in germinal centers.
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http://dx.doi.org/10.1016/j.immuni.2018.01.002DOI Listing
January 2018

Unconventional Pro-inflammatory CD4 T Cell Response in B Cell-Deficient Mice Infected with .

Front Immunol 2017 21;8:1548. Epub 2017 Nov 21.

Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI - CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.

Chagas disease, caused by the parasite , is endemic in Latin America but has become a global public health concern by migration of infected people. It has been reported that parasite persistence as well as the intensity of the inflammatory immune response are determinants of the clinical manifestations of the disease. Even though inflammation is indispensable for host defense, when deregulated, it can contribute to tissue injury and organ dysfunction. Here, we report the importance of B cells in conditioning T cell response in infection. Mice deficient in mature B cells (muMT mice) infected with exhibited an increase in plasma TNF concentration, TNF-producing CD4 T cells, and mortality. The increase in TNF-producing CD4 T cells was accompanied by a reduction in IFNγCD4 T cells and a decrease of the frequency of regulatory Foxp3, IL-10, and IL17CD4 T cells populations. The CD4 T cell population activated by infection, in absence of mature B cells, had a high frequency of Ly6C cells and showed a lower expression of inhibitory molecules such as CTLA-4, PD-1, and LAG3. CD4 T cells from infected muMT mice presented a high frequency of CD62LCD44 cells, which is commonly associated with a naïve phenotype. Through transfer experiments we demonstrated that CD4 T cells from infected muMT mice were able to condition the CD4 T cells response from infected wild-type mice. Interestingly, using Blimp-flox/flox-CD23icre mice we observed that in absence of plasmablast/plasma cell -infected mice exhibited a higher number of TNF-producing CD4 T cells. Our results showed that the absence of B cells during infection affected the T cell response at different levels and generated a favorable scenario for unconventional activation of CD4 T cell leading to an uncontrolled effector response and inflammation. The product of B cell differentiation, the plasmablast/plasma cells, could be able to regulate TNF-producing CD4 T cells since their absence favor the increase of the number of TNF CD4 in -infected mice.
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http://dx.doi.org/10.3389/fimmu.2017.01548DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5702327PMC
November 2017

Modulation of Roquin Function in Myeloid Cells Reduces -Induced Inflammation.

J Immunol 2017 09 26;199(5):1796-1804. Epub 2017 Jul 26.

Tuberculosis Research Program, Centenary Institute, Newtown, New South Wales 2042, Australia;

Damaging inflammation is a hallmark of infection, and understanding how this is regulated is important for the development of new therapies to limit excessive inflammation. The E3 ubiquitin ligase, Roquin, is involved in immune regulation; however, its role in immunity to is unknown. To address this, we infected mice with a point mutation in (). Aerosol-infected mice showed enhanced control of infection associated with delayed bacterial dissemination and upregulated TNF production in the lungs after 2 wk. However, this early control of infection was not maintained, and by 8 wk postinfection mice demonstrated an increased bacterial burden and dysregulated inflammation in the lungs. As the inflammation in the lungs of the mice could have been influenced by emerging autoimmune conditions that are characteristic of the mice aging, the function of Roquin was examined in immune cell subsets in the absence of autoimmune complications. bacillus Calmette-Guérin-primed T cells transferred into mice provided equivalent protection in the spleen and liver. Interestingly, the transfer of mycobacteria-specific (P25 CD4 TCR transgenic) wild-type spleen cells into mice actually led to enhanced protection with reduced bacterial load, decreased chemokine expression, and reduced inflammation in the lungs compared with transfers into mice expressing intact Roquin. These studies suggest that modulation of Roquin in myeloid cells may reduce both inflammation and bacterial growth during the chronic phase of infection.
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http://dx.doi.org/10.4049/jimmunol.1602069DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5570526PMC
September 2017

T-derived dopamine accelerates productive synapses in germinal centres.

Nature 2017 07 12;547(7663):318-323. Epub 2017 Jul 12.

Department of Immunology and Infectious Disease, John Curtin School of Medical Research, Australian National University, Canberra, Australian Capital Territory 2601, Australia.

Protective high-affinity antibody responses depend on competitive selection of B cells carrying somatically mutated B-cell receptors by follicular helper T (T) cells in germinal centres. The rapid T-B-cell interactions that occur during this process are reminiscent of neural synaptic transmission pathways. Here we show that a proportion of human T cells contain dense-core granules marked by chromogranin B, which are normally found in neuronal presynaptic terminals storing catecholamines such as dopamine. T cells produce high amounts of dopamine and release it upon cognate interaction with B cells. Dopamine causes rapid translocation of intracellular ICOSL (inducible T-cell co-stimulator ligand, also known as ICOSLG) to the B-cell surface, which enhances accumulation of CD40L and chromogranin B granules at the human T cell synapse and increases the synapse area. Mathematical modelling suggests that faster dopamine-induced T-B-cell interactions increase total germinal centre output and accelerate it by days. Delivery of neurotransmitters across the T-B-cell synapse may be advantageous in the face of infection.
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http://dx.doi.org/10.1038/nature23013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5540173PMC
July 2017

Plexin B2 and Semaphorin 4C Guide T Cell Recruitment and Function in the Germinal Center.

Cell Rep 2017 05;19(5):995-1007

Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China; Laboratory of Dynamic Immunobiology, Institute for Immunology, Tsinghua University, Beijing 100084, China; Department of Basic Medical Sciences, School of Medicine, Tsinghua University, Beijing 100084, China; School of Life Sciences, Tsinghua University, Beijing 100084, China. Electronic address:

Follicular T helper (T) cells orchestrate the germinal center (GC) response locally. T localization in GCs is controlled by chemo-guidance cues and antigen-specific adhesion. Here. we define an antigen-independent, contact-dependent, adhesive guidance system for T cells. Unusual for amoeboid cell migration, the system is composed of transmembrane plexin B2 (PlxnB2) molecule, which is highly expressed by GC B cells, and its transmembrane binding partner semaphorin 4C (Sema4C), which is upregulated on T cells. Sema4C on T cells serves as a receptor to sense the GC-presented PlxnB2 cue and biases T migration inwards at the GC edge to promote GC access. The absence of PlxnB2 from the GC or Sema4C from T cells causes T accumulation along the GC border, impairs T-B cell interactions in the GC, and is associated with defective plasma cell production and affinity maturation. Therefore, Sema4C and PlxnB2 regulate GC T recruitment and function and optimize antibody responses.
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http://dx.doi.org/10.1016/j.celrep.2017.04.022DOI Listing
May 2017

Germinal Center Lymphocyte Ratios and Successful HIV Vaccines.

Trends Mol Med 2017 02 12;23(2):95-97. Epub 2017 Jan 12.

Department of Immunology and Infectious Disease, John Curtin School of Medical Research, Australian National University, Canberra, Australia. Electronic address:

Current HIV vaccines are poor inducers of neutralizing antibodies (nAbs). A recent study in Cell Reports used serial fine-needle aspirates from rhesus macaque lymph nodes following HIV-1 surface envelope glycoprotein (Env) trimer immunization, generating a substantial production of HIV-1 nAbs. A remarkable correlation was found between antibody titers and a high frequency and ratio of germinal center B and T follicular helper (T) lymphocytes.
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http://dx.doi.org/10.1016/j.molmed.2016.12.009DOI Listing
February 2017

IL-27 Directly Enhances Germinal Center B Cell Activity and Potentiates Lupus in Sanroque Mice.

J Immunol 2016 10 12;197(8):3008-3017. Epub 2016 Sep 12.

Immunology Division, Garvan Institute of Medical Research, Darlinghurst, New South Wales 2010, Australia;

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 CD20CD38CD27CD95CD10 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 Roquin lupus mouse model. Il27raRoquin 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.
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http://dx.doi.org/10.4049/jimmunol.1600652DOI Listing
October 2016

T Follicular Helper Cells in Transplantation.

Transplantation 2016 Aug;100(8):1650-5

1 Department of Immunology and Infectious Disease, John Curtin School of Medical Research and Centre for Personalised Immunology, Australian National University, Canberra, Australia.2 Department of Renal Medicine, The Canberra Hospital, Canberra, Australia.3 Australian National University Medical School, Canberra, Australia.

The recently described T follicular helper (Tfh) cell is required for the production of high affinity antibody. After contact with follicular dendritic cells, Tfh cells move into the germinal centre and provide help to B cells both by direct B cell-T cell interaction and production of IL-21. This drives proliferation, differentiation, and affinity maturation of the B cells to produce plasma cells capable of secreting high-affinity antibody. Circulating Tfh cells are produced by movement of Tfh cells from lymph nodes after dendritic cell contact. A reduction of Tfh cell-associated molecules is linked with increased expression of other chemokine receptors to form Th1-, Th2-, and Th17-like Tfh cells. These circulating Tfh cells are able to help B cells in vitro and to move into target tissues to support antibody production. Alloantibody production is dependent on T-cell help via the indirect pathway. Antibody-mediated rejection is therefore dependent on Tfh cells. Animal data suggest that Tfh cells and B cells migrate to the allograft and are involved in alloantibody production within a tertiary lymphoid organ. There is some data supporting the same process within human allografts. The requirement for T-cell help provides a potential therapeutic target in the treatment of antibody-mediated rejection.
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http://dx.doi.org/10.1097/TP.0000000000001217DOI Listing
August 2016
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