Publications by authors named "Nicole A Mifsud"

48 Publications

Kinetics of Abacavir-Induced Remodelling of the Major Histocompatibility Complex Class I Peptide Repertoire.

Front Immunol 2021 19;12:672737. Epub 2021 May 19.

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

Abacavir hypersensitivity syndrome can occur in individuals expressing the HLA-B*57:01 major histocompatibility complex class I allotype when utilising the drug abacavir as a part of their anti-retroviral regimen. The drug is known to bind within the HLA-B*57:01 antigen binding cleft, leading to the selection of novel self-peptide ligands, thus provoking life-threatening immune responses. However, the sub-cellular location of abacavir binding and the mechanics of altered peptide selection are not well understood. Here, we probed the impact of abacavir on the assembly of HLA-B*57:01 peptide complexes. We show that whilst abacavir had minimal impact on the maturation or average stability of HLA-B*57:01 molecules, abacavir was able to differentially enhance the formation, selectively decrease the dissociation, and alter tapasin loading dependency of certain HLA-B*57:01-peptide complexes. Our data reveals a spectrum of abacavir mediated effects on the immunopeptidome which reconciles the heterogeneous functional T cell data reported in the literature.
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http://dx.doi.org/10.3389/fimmu.2021.672737DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8170132PMC
May 2021

CD8 T cell landscape in Indigenous and non-Indigenous people restricted by influenza mortality-associated HLA-A*24:02 allomorph.

Nat Commun 2021 05 18;12(1):2931. Epub 2021 May 18.

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

Indigenous people worldwide are at high risk of developing severe influenza disease. HLA-A*24:02 allele, highly prevalent in Indigenous populations, is associated with influenza-induced mortality, although the basis for this association is unclear. Here, we define CD8 T-cell immune landscapes against influenza A (IAV) and B (IBV) viruses in HLA-A*24:02-expressing Indigenous and non-Indigenous individuals, human tissues, influenza-infected patients and HLA-A*24:02-transgenic mice. We identify immunodominant protective CD8 T-cell epitopes, one towards IAV and six towards IBV, with A24/PB2-specific CD8 T cells being cross-reactive between IAV and IBV. Memory CD8 T cells towards these specificities are present in blood (CD27CD45RA phenotype) and tissues (CD103CD69 phenotype) of healthy individuals, and effector CD27CD45RAPD-1CD38CD8 T cells in IAV/IBV patients. Our data show influenza-specific CD8 T-cell responses in Indigenous Australians, and advocate for T-cell-mediated vaccines that target and boost the breadth of IAV/IBV-specific CD8 T cells to protect high-risk HLA-A*24:02-expressing Indigenous and non-Indigenous populations from severe influenza disease.
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http://dx.doi.org/10.1038/s41467-021-23212-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8132304PMC
May 2021

CD8 T cells specific for an immunodominant SARS-CoV-2 nucleocapsid epitope display high naive precursor frequency and TCR promiscuity.

Immunity 2021 05 15;54(5):1066-1082.e5. Epub 2021 Apr 15.

Department of Infectious Diseases, Austin Hospital, Heidelberg, VIC 3084, Australia; Department of Medicine and Radiology, The University of Melbourne, Parkville, VIC 3000, Australia; Data Analytics Research and Evaluation (DARE) Centre, Austin Health and The University of Melbourne, Heidelberg, VIC 3084, Australia.

To better understand primary and recall T cell responses during coronavirus disease 2019 (COVID-19), it is important to examine unmanipulated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific T cells. By using peptide-human leukocyte antigen (HLA) tetramers for direct ex vivo analysis, we characterized CD8 T cells specific for SARS-CoV-2 epitopes in COVID-19 patients and unexposed individuals. Unlike CD8 T cells directed toward subdominant epitopes (B7/N, A2/S, and A24/S) CD8 T cells specific for the immunodominant B7/N epitope were detected at high frequencies in pre-pandemic samples and at increased frequencies during acute COVID-19 and convalescence. SARS-CoV-2-specific CD8 T cells in pre-pandemic samples from children, adults, and elderly individuals predominantly displayed a naive phenotype, indicating a lack of previous cross-reactive exposures. T cell receptor (TCR) analyses revealed diverse TCRαβ repertoires and promiscuous αβ-TCR pairing within B7/NCD8 T cells. Our study demonstrates high naive precursor frequency and TCRαβ diversity within immunodominant B7/N-specific CD8 T cells and provides insight into SARS-CoV-2-specific T cell origins and subsequent responses.
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http://dx.doi.org/10.1016/j.immuni.2021.04.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8049468PMC
May 2021

Carbamazepine Induces Focused T Cell Responses in Resolved Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis Cases But Does Not Perturb the Immunopeptidome for T Cell Recognition.

Front Immunol 2021 12;12:653710. Epub 2021 Apr 12.

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

Antiseizure medications (ASMs) are frequently implicated in T cell-mediated drug hypersensitivity reactions and cause skin tropic pathologies that range in severity from mild rashes to life-threatening systemic syndromes. During the acute stages of the more severe manifestations of these reactions, drug responsive proinflammatory CD8 T cells display classical features of Th1 cytokine production ( IFNγ) and cytolysis ( granzyme B, perforin). These T cells may be found locally at the site of pathology ( blister cells/fluid), as well as systemically ( blood, organs). What is less understood are the long-lived immunological effects of the memory T cell pool following T cell-mediated drug hypersensitivity reactions. In this study, we examine the ASM carbamazepine (CBZ) and the CBZ-reactive memory T cell pool in patients who have a history of either Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN) from 3-to-20 years following their initial adverse reaction. We show that drug restimulation of CBZ-reactive CD8 T cells results in a proinflammatory profile and produces a mainly focused, yet private, T cell receptor (TCR) usage amongst human leukocyte antigen (HLA)-B*15:02-positive SJS or TEN patients. Additionally, we show that expression of these CBZ-reactive TCRs in a reporter cell line, lacking endogenous αβTCR, recapitulates the features of TCR activation reported for ASM-treated T cell lines/clones, providing a useful tool for further functional validations. Finally, we conduct a comprehensive evaluation of the HLA-B*15:02 immunopeptidome following ASM (or a metabolite) treatment of a HLA-B*15:02-positive B-lymphoblastoid cell line (C1R.B*15:02) and minor perturbation of the peptide repertoire. Collectively, this study shows that the CBZ-reactive T cells characterized require both the drug and HLA-B*15:02 for activation and that reactivation of memory T cells from blood results in a focused TCR profile in patients with resolved disease.
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http://dx.doi.org/10.3389/fimmu.2021.653710DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8071863PMC
April 2021

Resourcing, annotating, and analysing synthetic peptides of SARS-CoV-2 for immunopeptidomics and other immunological studies.

Proteomics 2021 Apr 2:e2100036. Epub 2021 Apr 2.

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

SARS-CoV-2 has caused a significant ongoing pandemic worldwide. A number of studies have examined the T cell mediated immune responses against SARS-CoV-2, identifying potential T cell epitopes derived from the SARS-CoV-2 proteome. Such studies will aid in identifying targets for vaccination and immune monitoring. In this study, we applied tandem mass spectrometry and proteomic techniques to a library of ∼40,000 synthetic peptides, in order to generate a large dataset of SARS-CoV-2 derived peptide MS/MS spectra. On this basis, we built an online knowledgebase, termed virusMS (https://virusms.erc.monash.edu/), to document, annotate and analyse these synthetic peptides and their spectral information. VirusMS incorporates a user-friendly interface to facilitate searching, browsing and downloading the database content. Detailed annotations of the peptides, including experimental information, peptide modifications, predicted peptide-HLA (human leukocyte antigen) binding affinities, and peptide MS/MS spectral data, are provided in virusMS.
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http://dx.doi.org/10.1002/pmic.202100036DOI Listing
April 2021

Thermostability profiling of MHC-bound peptides: a new dimension in immunopeptidomics and aid for immunotherapy design.

Nat Commun 2020 12 9;11(1):6305. Epub 2020 Dec 9.

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

The features of peptide antigens that contribute to their immunogenicity are not well understood. Although the stability of peptide-MHC (pMHC) is known to be important, current assays assess this interaction only for peptides in isolation and not in the context of natural antigen processing and presentation. Here, we present a method that provides a comprehensive and unbiased measure of pMHC stability for thousands of individual ligands detected simultaneously by mass spectrometry (MS). The method allows rapid assessment of intra-allelic and inter-allelic differences in pMHC stability and reveals profiles of stability that are broader than previously appreciated. The additional dimensionality of the data facilitated the training of a model which improves the prediction of peptide immunogenicity, specifically of cancer neoepitopes. This assay can be applied to any cells bearing MHC or MHC-like molecules, offering insight into not only the endogenous immunopeptidome, but also that of neoepitopes and pathogen-derived sequences.
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http://dx.doi.org/10.1038/s41467-020-20166-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7726561PMC
December 2020

A Shared TCR Bias toward an Immunogenic EBV Epitope Dominates in HLA-B*07:02-Expressing Individuals.

J Immunol 2020 09 19;205(6):1524-1534. Epub 2020 Aug 19.

Department of Medicine, Monash University, Central Clinical School, The Alfred Hospital, Melbourne, Victoria 3004, Australia;

EBV is one of the most common viruses found in humans and is prototypic of a persistent viral infection characterized by periods of latency. Across many HLA class I molecules, the latent-specific CD8 T cell response is focused on epitopes derived from the EBNA-3 protein family. In the case of HLA-B*07:02 restriction, a highly frequent class I allele, the T cell response is dominated by an epitope spanning residues 379-387 of EBNA-3 (RPPIFIRRL [EBV]). However, little is known about either the TCR repertoire specific for this epitope or the molecular basis for this observed immunodominance. The EBV CD8 T cell response was common among both EBV-seropositive HLA-B*07:02 healthy and immunocompromised individuals. Similar TCRs were identified in EBV-specific CD8 T cell repertoires across multiple HLA-B7 individuals, indicating a shared Ag-driven bias in TCR usage. In particular, TRBV4-1 and TRAV38 usage was observed in five out of six individuals studied. In this study, we report the crystal structure of a TRBV4-1 TCR-HLA-B*07:02/EBV complex, which provides a molecular basis for the observed TRBV4-1 bias. These findings enhance our understanding of the CD8 T cell response toward a common EBV determinant in HLA-B*07:02 individuals.
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http://dx.doi.org/10.4049/jimmunol.2000249DOI Listing
September 2020

In-depth mining of the immunopeptidome of an acute myeloid leukemia cell line using complementary ligand enrichment and data acquisition strategies.

Mol Immunol 2020 07 5;123:7-17. Epub 2020 May 5.

Department of Biochemistry and Molecular Biology and Infection and Immunity Program, Biomedicine Discovery Institute, Monash University, Clayton 3800, VIC, Australia. Electronic address:

The identification of T cell epitopes derived from tumour specific antigens remains a significant challenge for the development of peptide-based vaccines and immunotherapies. The use of mass spectrometry-based approaches (immunopeptidomics) can provide powerful new avenues for the identification of such epitopes. In this study we report the use of complementary peptide antigen enrichment methods and a comprehensive mass spectrometric acquisition strategy to provide in-depth immunopeptidome data for the THP-1 cell line, a cell line used widely as a model of human leukaemia. To accomplish this, we combined robust experimental workflows that incorporated ultrafiltration or off-line reversed phase chromatography to enrich peptide ligand as well as a multifaceted data acquisition strategy using an Orbitrap Fusion LC-MS instrument. Using the combined datasets from the two ligand enrichment methods we gained significant depth in immunopeptidome coverage by identifying a total of 41,816 HLA class I peptides from THP-1 cells, including a significant number of peptides derived from different oncogenes or over expressed proteins associated with cancer. The physicochemical properties of the HLA-bound peptides dictated their recovery using the two ligand enrichment approaches and their distribution across the different precursor charge states considered in the data acquisition strategy. The data highlight the complementarity of the two enrichment procedures, and in cases where sample is not limiting, suggest that the combination of both approaches will yield the most comprehensive immunopeptidome information.
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http://dx.doi.org/10.1016/j.molimm.2020.04.008DOI Listing
July 2020

The complexity of T cell-mediated penicillin hypersensitivity reactions.

Allergy 2021 01 6;76(1):150-167. Epub 2020 Jul 6.

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

Penicillin refers to a group of beta-lactam antibiotics that are the first-line treatment for a range of infections. However, they also possess the ability to form novel antigens, or neoantigens, through haptenation of proteins and can stimulate a range of immune-mediated adverse reactions-collectively known as drug hypersensitivity reactions (DHRs). IgE-mediated reactions towards these neoantigens are well studied; however, IgE-independent reactions are less well understood. These reactions usually manifest in a delayed manner as different forms of cutaneous eruptions or liver injury consistent with priming of an immune response. Ex vivo studies have confirmed the infiltration of T cells into the site of inflammation, and the subsets of T cells involved appear dependent on the nature of the reaction. Here, we review the evidence that has led to our current understanding of these immune-mediated reactions, discussing the nature of the lesional T cells, the characterization of drug-responsive T cells isolated from patient blood, and the potential mechanisms by which penicillins enter the antigen processing and presentation pathway to stimulate these deleterious responses. Thus, we highlight the need for a more comprehensive understanding of the underlying genetic and molecular basis of penicillin-induced DHRs.
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http://dx.doi.org/10.1111/all.14355DOI Listing
January 2021

Preferential HLA-B27 Allorecognition Displayed by Multiple Cross-Reactive Antiviral CD8 T Cell Receptors.

Front Immunol 2020 19;11:248. Epub 2020 Feb 19.

Respiratory Medicine Laboratory, Department of Medicine, Central Clinical School, Monash University, Melbourne, VIC, Australia.

T cells provide essential immunosurveillance to combat and eliminate infection from pathogens, yet these cells can also induce unwanted immune responses via T cell receptor (TCR) cross-reactivity, also known as heterologous immunity. Indeed, pathogen-induced TCR cross-reactivity has shown to be a common, robust, and functionally potent mechanism that can trigger a spectrum of human immunopathologies associated with either transplant rejection, drug allergy, and autoimmunity. Here, we report that several virus-specific CD8 T cells directed against peptides derived from chronic viruses (EBV, CMV, and HIV-1) presented by high frequency HLA-A and -B allomorphs differentially cross-react toward HLA-B27 allotypes in a highly focused and hierarchical manner. Given the commonality of cross-reactive T cells and their potential contribution to adverse outcomes in allogeneic transplants, our study demonstrates that multiple antiviral T cells recognizing the same HLA allomorph could pose an extra layer of complexity for organ matching.
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http://dx.doi.org/10.3389/fimmu.2020.00248DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7042382PMC
March 2021

Response to Comment on "A subset of HLA-I peptides are not genomically templated: Evidence for cis- and trans-spliced peptide ligands".

Sci Immunol 2019 08;4(38)

Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia.

This is our response to the Technical Comment by Rolfs where we point out errors in their reanalysis of our data.
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http://dx.doi.org/10.1126/sciimmunol.aaw8457DOI Listing
August 2019

Downregulation of MHC Class I Expression by Influenza A and B Viruses.

Front Immunol 2019 29;10:1158. Epub 2019 May 29.

Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Parkville, VIC, Australia.

Manipulation of the MHC-I presentation pathway, and thus limiting MHC-I cell surface expression, is used by many viruses to evade immune recognition. In particular, downregulation of MHC-I molecules at the cell surface can reduce the ability of CD8 T cells to recognize viral peptides presented by MHC-I molecules and thereby delay viral clearance by CD8 T cells. To date, MHC-I downregulation by influenza viruses has not been reported. Given that influenza virus infections are a global health concern and that CD8 T cells play an important role in promoting influenza virus clearance and recovery from influenza disease, we investigated whether influenza A and B viruses (IAV, IBV) downregulated MHC-I as a novel mechanism to evade cellular immunity. Here, we showed that infection of several cell types, including epithelial A549 cells, with a panel of IAV and IBV viruses downregulated the surface MHC-I expression on IAV/IBV-infected cells during the late stages of influenza virus infection . This observation was consistent across a panel of class I-reduced (C1R) cell lines expressing 14 different HLA-A or -B alleles and a panel of 721.221 cell lines expressing 11 HLA-C alleles. Interestingly, IBV infection caused more pronounced reduction in surface MHC-I expression compared to IAV. Importantly, the two viruses utilized two distinct mechanisms for MHC-I downregulation. Our data demonstrated that while IAV caused a global loss of MHC-I within influenza-infected cells, IBV infection resulted in the preferential loss of MHC-I molecules from the cell surface, consequent of delayed MHC-I trafficking to the cell surface, resulting from retaining MHC-I intracellularly during IBV infection. Overall, our study suggests that influenza viruses across both IAV and IBV subtypes have the potential to downregulate MHC-I surface expression levels. Our findings provide new insights into the host-pathogen interaction of influenza A and B viruses and inform the design of novel vaccine strategies against influenza viruses.
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http://dx.doi.org/10.3389/fimmu.2019.01158DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6548845PMC
July 2020

Influenza A Virus Infection Induces Viral and Cellular Defective Ribosomal Products Encoded by Alternative Reading Frames.

J Immunol 2019 06 15;202(12):3370-3380. Epub 2019 May 15.

Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria 3086, Australia;

The importance of antiviral CD8 T cell recognition of alternative reading frame (ARF)-derived peptides is uncertain. In this study, we describe an epitope (NS1-ARF2) present in a predicted 14-residue peptide encoded by the +1 register of NS1 mRNA in the influenza A virus (IAV). NS1-ARF2 elicits a robust, highly functional CD8 T cell response in IAV-infected BALB/c mice. NS1-ARF2 is presented from unspliced NS mRNA, likely from downstream initiation on a Met residue that comprises the P1 position of NS1-ARF2 Derived from a 14-residue peptide with no apparent biological function and negligible impacts on IAV infection, infectivity, and pathogenicity, NS1-ARF2 provides a clear demonstration of how immunosurveillance exploits natural errors in protein translation to provide antiviral immunity. We further show that IAV infection enhances a model cellular ARF translation, which potentially has important implications for virus-induced autoimmunity.
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http://dx.doi.org/10.4049/jimmunol.1900070DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6681668PMC
June 2019

HLA-associated antiepileptic drug-induced cutaneous adverse reactions.

HLA 2019 06 9;93(6):417-435. Epub 2019 Apr 9.

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

Adverse drug reactions (ADRs) are a common cause of hospital admissions (up to 19%), with the majority of cases due to off-target predictable drug effects (type A reactions). However, idiosyncratic drug-induced immune activated (type B) reactions contribute to a range of hypersensitivity reactions, with T-cell-mediated type IV hypersensitivity reactions mainly manifesting as cutaneous ADRs (cADRs). Aromatic antiepileptic drugs (AEDs), used in the treatment of epilepsy as well as bipolar disorder or neuropathic pain, have been implicated as culprit drugs in a spectrum of pathologies ranging from mild maculopapular exanthema (MPE) to severe and life-threatening conditions including drug reaction with eosinophilia and systemic symptoms (DRESS), Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). These AED-induced cADRs are unpredictable based on pharmacological and clinical factors alone, thereby prompting investigations into genomic contributors mediating risk of pathology. The most strongly associated risk genes identified are from the human leukocyte antigen (HLA) class I alleles, which play a critical role in adaptive immunity by flagging either infected or aberrant cells for recognition by surveying T-cells. In the setting of drug hypersensitivity, the immunogenicity of HLA molecules and their peptide cargo can be modulated by interactions with small drug molecules that drive inappropriate T-cell responses. This review discusses the current understanding of HLA class I molecules in modifying risk of AED-induced cADRs.
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http://dx.doi.org/10.1111/tan.13530DOI Listing
June 2019

Human CD8 T cell cross-reactivity across influenza A, B and C viruses.

Nat Immunol 2019 05 18;20(5):613-625. Epub 2019 Feb 18.

Department of Microbiology and Immunology, University of Melbourne, at the Peter Doherty Institute for Infection and Immunity, Parkville, Victoria, Australia.

Influenza A, B and C viruses (IAV, IBV and ICV, respectively) circulate globally and infect humans, with IAV and IBV causing the most severe disease. CD8 T cells confer cross-protection against IAV strains, however the responses of CD8 T cells to IBV and ICV are understudied. We investigated the breadth of CD8 T cell cross-recognition and provide evidence of CD8 T cell cross-reactivity across IAV, IBV and ICV. We identified immunodominant CD8 T cell epitopes from IBVs that were protective in mice and found memory CD8 T cells directed against universal and influenza-virus-type-specific epitopes in the blood and lungs of healthy humans. Lung-derived CD8 T cells displayed tissue-resident memory phenotypes. Notably, CD38Ki67CD8 effector T cells directed against novel epitopes were readily detected in IAV- or IBV-infected pediatric and adult subjects. Our study introduces a new paradigm whereby CD8 T cells confer unprecedented cross-reactivity across all influenza viruses, a key finding for the design of universal vaccines.
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http://dx.doi.org/10.1038/s41590-019-0320-6DOI Listing
May 2019

HLA-B57 micropolymorphism defines the sequence and conformational breadth of the immunopeptidome.

Nat Commun 2018 11 8;9(1):4693. Epub 2018 Nov 8.

Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia.

Immunophenotypic differences between closely related human leukocyte antigen (HLA) alleles have been associated with divergent clinical outcomes in infection, autoimmunity, transplantation and drug hypersensitivity. Here we explore the impact of micropolymorphism on peptide antigen presentation by three closely related HLA molecules, HLA-B*57:01, HLA-B*57:03 and HLA-B*58:01, that are differentially associated with the HIV elite controller phenotype and adverse drug reactions. For each allotype, we mine HLA ligand data sets derived from the same parental cell proteome to define qualitative differences in peptide presentation using classical peptide binding motifs and an unbiased statistical approach. The peptide repertoires show marked qualitative overlap, with 982 peptides presented by all allomorphs. However, differences in peptide abundance, HLA-peptide stability, and HLA-bound conformation demonstrate that HLA micropolymorphism impacts more than simply the range of peptide ligands. These differences provide grounds for distinct immune reactivity and insights into the capacity of micropolymorphism to diversify immune outcomes.
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http://dx.doi.org/10.1038/s41467-018-07109-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6224591PMC
November 2018

A subset of HLA-I peptides are not genomically templated: Evidence for cis- and trans-spliced peptide ligands.

Sci Immunol 2018 10;3(28)

Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia.

The diversity of peptides displayed by class I human leukocyte antigen (HLA) plays an essential role in T cell immunity. The peptide repertoire is extended by various posttranslational modifications, including proteasomal splicing of peptide fragments from distinct regions of an antigen to form nongenomically templated cis-spliced sequences. Previously, it has been suggested that a fraction of the immunopeptidome constitutes such cis-spliced peptides; however, because of computational limitations, it has not been possible to assess whether trans-spliced peptides (i.e., the fusion of peptide segments from distinct antigens) are also bound and presented by HLA molecules, and if so, in what proportion. Here, we have developed and applied a bioinformatic workflow and demonstrated that trans-spliced peptides are presented by HLA-I, and their abundance challenges current models of proteasomal splicing that predict cis-splicing as the most probable outcome. These trans-spliced peptides display canonical HLA-binding sequence features and are as frequently identified as cis-spliced peptides found bound to a number of different HLA-A and HLA-B allotypes. Structural analysis reveals that the junction between spliced peptides is highly solvent exposed and likely to participate in T cell receptor interactions. These results highlight the unanticipated diversity of the immunopeptidome and have important implications for autoimmunity, vaccine design, and immunotherapy.
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http://dx.doi.org/10.1126/sciimmunol.aar3947DOI Listing
October 2018

Inability To Detect Cross-Reactive Memory T Cells Challenges the Frequency of Heterologous Immunity among Common Viruses.

J Immunol 2018 06 7;200(12):3993-4003. Epub 2018 May 7.

Department of Medicine, Monash University, Central Clinical School, The Alfred Hospital, Melbourne, Victoria 3004, Australia;

Human memory T cells that cross-react with epitopes from unrelated viruses can potentially modulate immune responses to subsequent infections by a phenomenon termed heterologous immunity. However, it is unclear whether similarities in structure rather than sequence underpin heterologous T cell cross-reactivity. In this study, we aimed to explore the mechanism of heterologous immunity involving immunodominant epitopes derived from common viruses restricted to high-frequency HLA allotypes (HLA-A*02:01, -B*07:02, and -B*08:01). We examined EBV-specific memory T cells for their ability to cross-react with CMV or influenza A virus-derived epitopes. Following T cell immunoassays to determine phenotype and function, complemented with biophysical and structural investigations of peptide/HLA complexes, we did not detect cross-reactivity of EBV-specific memory T cells toward either CMV or influenza A virus epitopes presented by any of the selected HLA allomorphs. Thus, despite the ubiquitous nature of these human viruses and the dominant immune response directed toward the selected epitopes, heterologous virus-specific T cell cross-reactivity was not detected. This suggests that either heterologous immunity is not as common as previously reported, or that it requires a very specific biological context to develop and be clinically relevant.
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http://dx.doi.org/10.4049/jimmunol.1800010DOI Listing
June 2018

Identification of Native and Posttranslationally Modified HLA-B*57:01-Restricted HIV Envelope Derived Epitopes Using Immunoproteomics.

Proteomics 2018 06 10;18(12):e1700253. Epub 2018 Apr 10.

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

The recognition of pathogen-derived peptides by T lymphocytes is the cornerstone of adaptive immunity, whereby intracellular antigens are degraded in the cytosol and short peptides assemble with class I human leukocyte antigen (HLA) molecules in the ER. These peptide-HLA complexes egress to the cell surface and are scrutinized by cytotoxic CD8+ T-cells leading to the eradication of the infected cell. Here, naturally presented HLA-B*57:01 bound peptides derived from the envelope protein of the human immunodeficiency virus (HIVenv) are identified. HIVenv peptides are present at a very small percentage of the overall HLA-B*57:01 peptidome (<0.1%) and both native and posttranslationally modified forms of two distinct HIV peptides are identified. Notably, a peptide bearing a natively encoded C-terminal tryptophan residue is also present in a modified form containing a kynurenine residue. Kynurenine is a major product of tryptophan catabolism and is abundant during inflammation and infection. Binding of these peptides at a molecular level and their immunogenicity in preliminary functional studies are examined. Modest immune responses are observed to the modified HIVenv peptide, highlighting a potential role for kynurenine-modified peptides in the immune response to HIV and other viral infections.
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http://dx.doi.org/10.1002/pmic.201700253DOI Listing
June 2018

Allotype specific interactions of drugs and HLA molecules in hypersensitivity reactions.

Curr Opin Immunol 2016 10 2;42:31-40. Epub 2016 Jun 2.

Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton 3800, Victoria, Australia.

It is hypothesised that associations between adverse drug reactions and specific alleles of the human leukocyte antigens arise due to specific interactions between the human leukocyte antigen molecules and the causative drug that stimulate immune responses targeting drug exposed tissues. To date this has only been definitively demonstrated for abacavir, an antiretroviral that causes a systemic adverse drug reaction, abacavir hypersensitivity syndrome, solely in HLA-B*57:01 individuals. Whilst this has informed the modification of abacavir to remove immunogenicity, there remains an imperative to define other interactions between drugs and specific HLA in order to understand the scope of interactions that can drive T cell mediated drug hypersensitivity. Here we review the current state of understanding of these interactions.
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http://dx.doi.org/10.1016/j.coi.2016.05.003DOI Listing
October 2016

Maintenance of the EBV-specific CD8 TCRαβ repertoire in immunosuppressed lung transplant recipients.

Immunol Cell Biol 2017 01 4;95(1):77-86. Epub 2016 Oct 4.

Department of Microbiology and Immunology, University of Melbourne, at the Peter Doherty Institute for Infection and Immunity, Parkville, VIC, Australia.

Epstein-Barr virus (EBV) is one of the most common viruses in humans, capable of causing life-threatening infections and cancers in immunocompromised individuals. Although CD8 T cells provide key protection against EBV, the persistence and dynamics of specific T-cell receptor (TCR) clones during immunosuppression in transplant patients is largely unknown. For the first time, we used a novel single-cell TCRαβ multiplex-nested reverse transcriptase PCR to dissect TCRαβ clonal diversity within GLCTLVAML (GLC)-specific CD8 T cells in healthy individuals and immunocompromised lung transplant recipients. The GLC peptide presented by HLA-A*02:01 is one of the most immunogenic T-cell targets from the EBV proteome. We found that the GLC-specific TCRαβ repertoire was heavily biased toward TRAV5 and encompassed five classes of public TCRαβs, suggesting that these clonotypes are preferentially utilized following infection. We identified that a common TRAV5 was diversely paired with different TRAJ and TRBV/TRBJ genes, in both immunocompetent and immunocompromised individuals, with an average of 12 different TCRαβ clonotypes/donor. Moreover, pre-transplant GLC-specific TCRαβ repertoires were relatively stable over 1 year post transplant under immunosuppression in the absence or presence of EBV reactivation. In addition, we provide the first evidence of early GLC-specific CD8 T cells at 87 days post transplant, which preceded clinical EBV detection at 242 days in an EBV-seronegative patient receiving a lung allograft from an EBV-seropositive donor. This was associated with a relatively stable TCRαβ repertoire after CD8 T-cell expansion. Our findings provide insights into the composition and temporal dynamics of the EBV-specific TCRαβ repertoire in immunocompromised transplant patients and suggest that the early detection of EBV-specific T cells might be a predictor of ensuing EBV blood viremia.
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http://dx.doi.org/10.1038/icb.2016.71DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5214975PMC
January 2017

Deciphering the clinical relevance of allo-human leukocyte antigen cross-reactivity in mediating alloimmunity following transplantation.

Curr Opin Organ Transplant 2016 Feb;21(1):29-39

aDepartment of Allergy, Immunology and Respiratory Medicine, The Alfred Hospital, Commercial Road, Melbourne bInfection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton cDepartment of Microbiology and Immunology, The University of Melbourne, The Peter Doherty Institute for Infection and Immunity, Parkville dAustralian Research Council Centre of Excellence for Advanced Molecular Imaging eDepartment of Medicine, Central Clinical School, Monash University, Clayton, VIC, Australia.

Purpose Of Review: Despite a growing awareness regarding the potential of cross-reactive virus-specific memory T cells to mediate alloimmunity, there has been limited clinical evaluation on allograft immunopathology. This review will explore published models of human T-cell cross-reactivity and discuss criteria required to drive this mechanism as a contributing cause of allograft dysfunction in transplantation.

Recent Findings: Published models of human allogeneic (allo)-human leukocyte antigen (HLA) cross-reactivity have enabled dissection of the cross-reactive T cell receptor/peptide/major histocompatibility complex (TCR/peptide/MHC) interaction. In many of the models, the cross-reactive T cells express a unique TCR, although the relevance of a public cross-reactive TCR repertoire has yet to be determined. Equally, allopeptide identity, a vital component driving cross-recognition, remains unknown in the majority of models thereby prompting further characterization utilizing novel technologies. Although clinical studies examining the presence and impact of specific cross-reactive virus-specific T cells have been minimally explored, the existing data suggest that there may be a marginal set of requirements that need to be satisfied before the potentially damaging effects of allo-HLA cross-reactivity can be realized.

Summary: Our understanding of allo-HLA cross-reactivity continues to evolve as improved technology and novel strategies allow us to better question the contribution of allo-HLA cross-reactivity in clinically relevant allograft dysfunction.
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http://dx.doi.org/10.1097/MOT.0000000000000264DOI Listing
February 2016

The Presence of HLA-E-Restricted, CMV-Specific CD8+ T Cells in the Blood of Lung Transplant Recipients Correlates with Chronic Allograft Rejection.

PLoS One 2015 24;10(8):e0135972. Epub 2015 Aug 24.

Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Parkville, Victoria, Australia.

The human cytomegalovirus (CMV) immune evasion protein, UL40, shares an identical peptide sequence with that found in the leader sequence of many human leukocyte antigen (HLA)-C alleles and when complexed with HLA-E, can modulate NK cell functions via interactions with the CD94-NKG2 receptors. However the UL40-derived sequence can also be immunogenic, eliciting robust CD8+ T cell responses. In the setting of solid organ transplantation these T cells may not only be involved in antiviral immunity but also can potentially contribute to allograft rejection when the UL40 epitope is also present in allograft-encoded HLA. Here we assessed 15 bilateral lung transplant recipients for the presence of HLA-E-restricted UL40 specific T cells by tetramer staining of peripheral blood mononuclear cells (PBMC). UL40-specific T cells were observed in 7 patients post-transplant however the magnitude of the response varied significantly between patients. Moreover, unlike healthy CMV seropositive individuals, longitudinal analyses revealed that proportions of such T cells fluctuated markedly. Nine patients experienced low-grade acute cellular rejection, of which 6 also demonstrated UL40-specific T cells. Furthermore, the presence of UL40-specific CD8+ T cells in the blood was significantly associated with allograft dysfunction, which manifested as Bronchiolitis Obliterans Syndrome (BOS). Therefore, this study suggests that minor histocompatibility antigens presented by HLA-E can represent an additional risk factor following lung transplantation.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0135972PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4547726PMC
May 2016

Dendritic Cell-Mediated Phagocytosis but Not Immune Activation Is Enhanced by Plasmin.

PLoS One 2015 1;10(7):e0131216. Epub 2015 Jul 1.

Australian Centre for Blood Diseases, Monash University, Alfred Medical Research and Education Precinct, Melbourne, 3004, Victoria Australia.

Removal of dead cells in the absence of concomitant immune stimulation is essential for tissue homeostasis. We recently identified an injury-induced protein misfolding event that orchestrates the plasmin-dependent proteolytic degradation of necrotic cells. As impaired clearance of dead cells by the innate immune system predisposes to autoimmunity, we determined whether plasmin could influence endocytosis and immune cell stimulation by dendritic cells - a critical cell that links the innate and adaptive immune systems. We find that plasmin generated on the surface of necrotic cells enhances their phagocytic removal by human monocyte-derived dendritic cells. Plasmin also promoted phagocytosis of protease-resistant microparticles by diverse mouse dendritic cell sub-types both in vitro and in vivo. Together with an increased phagocytic capacity, plasmin-treated dendritic cells maintain an immature phenotype, exhibit reduced migration to lymph nodes, increase their expression/release of the immunosuppressive cytokine TGF-β, and lose their capacity to mount an allogeneic response. Collectively, our findings support a novel role for plasmin formed on dead cells and other phagocytic targets in maintaining tissue homeostasis by increasing the phagocytic function of dendritic cells while simultaneously decreasing their immunostimulatory capacity consistent with producing an immunosuppressive state.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0131216PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4488505PMC
April 2016

The activin A antagonist follistatin inhibits cystic fibrosis-like lung inflammation and pathology.

Immunol Cell Biol 2015 Jul 10;93(6):567-74. Epub 2015 Mar 10.

1] Department of Allergy, Immunology & Respiratory Medicine, Central Clinical School, Monash University, Melbourne, Victoria, Australia [2] Department of Immunology, Central Clinical School, Monash University, Melbourne, Victoria, Australia [3] Department of Allergy, Immunology & Respiratory Medicine, The Alfred Hospital, Melbourne, Victoria, Australia.

Cystic fibrosis (CF) is the most common life-limiting genetically acquired respiratory disorder. Patients with CF have thick mucus obstructing the airways leading to recurrent infections, bronchiectasis and neutrophilic airway inflammation culminating in deteriorating lung function. Current management targets airway infection and mucus clearance, but despite recent advances in care, life expectancy is still only 40 years. We investigated whether activin A is elevated in CF lung disease and whether inhibiting activin A with its natural antagonist follistatin retards lung disease progression. We measured serum activin A levels, lung function and nutritional status in CF patients. We studied the effect of activin A on CF lung pathogenesis by treating newborn CF transgenic mice (β-ENaC) intranasally with the natural activin A antagonist follistatin. Activin A levels were elevated in the serum of adult CF patients, and correlated inversely with lung function and body mass index. Follistatin treatment of newborn β-ENaC mice, noted for respiratory pathology mimicking human CF, decreased the airway activin A levels and key features of CF lung disease including mucus hypersecretion, airway neutrophilia and levels of mediators that regulate inflammation and chemotaxis. Follistatin treatment also increased body weight and survival of β-ENaC mice, with no evidence of local or systemic toxicity. Our findings demonstrate that activin A levels are elevated in CF and provide proof-of-concept for the use of the activin A antagonist, follistatin, as a therapeutic in the long-term management of lung disease in CF patients.
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http://dx.doi.org/10.1038/icb.2015.7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4495664PMC
July 2015

The oral iron chelator deferasirox inhibits NF-κB mediated gene expression without impacting on proximal activation: implications for myelodysplasia and aplastic anaemia.

Br J Haematol 2015 Feb 1;168(4):576-82. Epub 2014 Oct 1.

Centre for Cancer Research, MIMR-PHI Institute of Medical Research, Clayton, Vic., Australia; Centre for Inflammatory Diseases, Monash University, Clayton, Vic., Australia.

The myelodysplastic syndromes (MDS) are a group of disorders characterized by ineffective haematopoiesis, bone marrow dysplasia and cytopenias. Failure of red cell production often results in transfusion dependency with subsequent iron loading requiring iron chelation in lower risk patients. Consistent with previous reports, we have observed haematopoietic improvement in a cohort of patients treated with the oral iron chelator deferasirox (DFX). It has been postulated that MDS patients have a pro-inflammatory bone marrow environment with increased numbers of activated T cells producing elevated levels of tumour necrosis factor (TNF), which is detrimental to normal haematopoiesis. We demonstrate that DFX inhibits nuclear factor (NF)-κB dependent transcription without affecting its proximal activation, resulting in reduced TNF production from T cells stimulated in vitro. These results suggest that the haematopoietic improvement observed in DFX-treated patients may reflect an anti-inflammatory effect, mediated through inhibition of the transcription factor NF-κB and support the therapeutic targeting of this pathway, which is aberrantly activated in a large proportion of haematological malignancies.
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http://dx.doi.org/10.1111/bjh.13151DOI Listing
February 2015

Recognition of distinct cross-reactive virus-specific CD8+ T cells reveals a unique TCR signature in a clinical setting.

J Immunol 2014 Jun 28;192(11):5039-49. Epub 2014 Apr 28.

Department of Medicine, Monash University, Central Clinical School, The Alfred Centre, Melbourne, Victoria 3004, Australia; Department of Allergy, Immunology and Respiratory Medicine, The Alfred Hospital, Melbourne, Victoria 3004, Australia;

Human CMV still remains problematic in immunocompromised patients, particularly after solid organ transplantation. CMV primary disease and reactivation greatly increase the risks associated with incidences of chronic allograft rejection and decreased survival in transplant recipients. But whether this is due to direct viral effects, indirect viral effects including cross-reactive antiviral T cell immunopathology, or a combination of both remains undetermined. In this article, we report the novel TCR signature of cross-reactive HLA-A*02:01 (A2) CMV (NLVPMVATV [NLV])-specific CD8(+) T cells recognizing a specific array of HLA-B27 alleles using technical advancements that combine both IFN-γ secretion and multiplex nested RT-PCR for determining paired CDR3α/β sequences from a single cell. This study represents the first evidence, to our knowledge, of the same A2-restricted cross-reactive NLV-specific TCR-α/β signature (TRAV3TRAJ31_TRBV12-4TRBJ1-1) in two genetically distinct individuals. Longitudinal posttransplant monitoring of a lung transplant recipient (A2, CMV seropositive) who received a HLA-B27 bilateral lung allograft showed a dynamic expansion of the cross-reactive NLV-specific TCR repertoire before CMV reactivation. After resolution of the active viral infection, the frequency of cross-reactive NLV-specific CD8(+) T cells reduced to previremia levels, thereby demonstrating immune modulation of the T cell repertoire due to antigenic pressure. The dynamic changes in TCR repertoire, at a time when CMV reactivation was subclinical, illustrates that prospective monitoring in susceptible patients can reveal nuances in immune profiles that may be clinically relevant.
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http://dx.doi.org/10.4049/jimmunol.1303147DOI Listing
June 2014

Impact of commonly used transplant immunosuppressive drugs on human NK cell function is dependent upon stimulation condition.

PLoS One 2013 21;8(3):e60144. Epub 2013 Mar 21.

Department of Medicine, Monash University, Melbourne, Victoria, Australia.

Lung transplantation is a recognised treatment for patients with end stage pulmonary disease. Transplant recipients receive life-long administration of immunosuppressive drugs that target T cell mediated graft rejection. However little is known of the impact on NK cells, which have the potential to be alloreactive in response to HLA-mismatched ligands on the lung allograft and in doing so, may impact negatively on allograft survival. NK cells from 20 healthy controls were assessed in response to Cyclosporine A, Mycophenolic acid (MPA; active form of Mycophenolate mofetil) and Prednisolone at a range of concentrations. The impact of these clinically used immunosuppressive drugs on cytotoxicity (measured by CD107a expression), IFN-γ production and CFSE proliferation was assessed in response to various stimuli including MHC class-I negative cell lines, IL-2/IL-12 cytokines and PMA/Ionomycin. Treatment with MPA and Prednisolone revealed significantly reduced CD107a expression in response to cell line stimulation. In comparison, addition of MPA and Cyclosporine A displayed reduced CD107a expression and IFN-γ production following PMA/Ionomycin stimulation. Diminished proliferation was observed in response to treatment with each drug. Additional functional inhibitors (LY294002, PD98059, Rottlerin, Rapamycin) were used to elucidate intracellular pathways of NK cell activation in response to stimulation with K562 or PMA-I. CD107a expression was significantly decreased with the addition of PD98059 following K562 stimulation. Similarly, CD107a expression significantly decreased following PMA-I stimulation with the addition of LY294002, PD98059 and Rottlerin. Ten lung transplant patients, not receiving immunosuppressive drugs pre-transplant, were assessed for longitudinal changes post-transplant in relation to the administration of immunosuppressive drugs. Individual patient dynamics revealed different longitudinal patterns of NK cell function post-transplantation. These results provide mechanistic insights into pathways of NK cell activation and show commonly administered transplant immunosuppression agents and clinical rejection/infection events have differential effects on NK cell function that may impact the immune response following lung transplantation.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0060144PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3605368PMC
September 2013

Cross-reactive anti-viral T cells increase prior to an episode of viral reactivation post human lung transplantation.

PLoS One 2013 6;8(2):e56042. Epub 2013 Feb 6.

Department of Medicine, Monash University, Central Clinical School, The Alfred Centre, Melbourne, Victoria, Australia.

Human Cytomegalovirus (CMV) reactivation continues to influence lung transplant outcomes. Cross-reactivity of anti-viral memory T cells against donor human leukocyte antigens (HLA) may be a contributing factor. We identified cross-reactive HLA-A*02:01-restricted CMV-specific cytotoxic T lymphocytes (CTL) co-recognizing the NLVPMVATV (NLV) epitope and HLA-B27. NLV-specific CD8+ T cells were expanded for 13 days from 14 HLA-A*02:01/CMV seropositive healthy donors and 11 lung transplant recipients (LTR) then assessed for the production of IFN-γ and CD107a expression in response to 19 cell lines expressing either single HLA-A or -B class I molecules. In one healthy individual, we observed functional and proliferative cross-reactivity in response to B*27:05 alloantigen, representing approximately 5% of the NLV-specific CTL population. Similar patterns were also observed in one LTR receiving a B27 allograft, revealing that the cross-reactive NLV-specific CTL gradually increased (days 13-193 post-transplant) before a CMV reactivation event (day 270) and reduced to basal levels following viral clearance (day 909). Lung function remained stable with no acute rejection episodes being reported up to 3 years post-transplant. Individualized immunological monitoring of cross-reactive anti-viral T cells will provide further insights into their effects on the allograft and an opportunity to predict sub-clinical CMV reactivation events and immunopathological complications.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0056042PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3566045PMC
August 2013

A novel HLA-B18 restricted CD8+ T cell epitope is efficiently cross-presented by dendritic cells from soluble tumor antigen.

PLoS One 2012 6;7(9):e44707. Epub 2012 Sep 6.

Ludwig Institute for Cancer Research, Melbourne Austin Branch, Austin Health, Heidelberg, Victoria, Australia.

NY-ESO-1 has been a major target of many immunotherapy trials because it is expressed by various cancers and is highly immunogenic. In this study, we have identified a novel HLA-B*1801-restricted CD8(+) T cell epitope, NY-ESO-1(88-96) (LEFYLAMPF) and compared its direct- and cross-presentation to that of the reported NY-ESO-1(157-165) epitope restricted to HLA-A*0201. Although both epitopes were readily cross-presented by DCs exposed to various forms of full-length NY-ESO-1 antigen, remarkably NY-ESO-1(88-96) is much more efficiently cross-presented from the soluble form, than NY-ESO-1(157-165). On the other hand, NY-ESO-1(157-165) is efficiently presented by NY-ESO-1-expressing tumor cells and its presentation was not enhanced by IFN-γ treatment, which induced immunoproteasome as demonstrated by Western blots and functionally a decreased presentation of Melan A(26-35); whereas NY-ESO-1(88-96) was very inefficiently presented by the same tumor cell lines, except for one that expressed high level of immunoproteasome. It was only presented when the tumor cells were first IFN-γ treated, followed by infection with recombinant vaccinia virus encoding NY-ESO-1, which dramatically increased NY-ESO-1 expression. These data indicate that the presentation of NY-ESO-1(88-96) is immunoproteasome dependent. Furthermore, a survey was conducted on multiple samples collected from HLA-B18(+) melanoma patients. Surprisingly, all the detectable responses to NY-ESO-1(88-96) from patients, including those who received NY-ESO-1 ISCOMATRIX™ vaccine were induced spontaneously. Taken together, these results imply that some epitopes can be inefficiently presented by tumor cells although the corresponding CD8(+) T cell responses are efficiently primed in vivo by DCs cross-presenting these epitopes. The potential implications for cancer vaccine strategies are further discussed.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0044707PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3435279PMC
March 2013