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3.
Proc Natl Acad Sci U S A ; 118(49)2021 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-34845016

RESUMO

Unlike conventional αß T cells, γδ T cells typically recognize nonpeptide ligands independently of major histocompatibility complex (MHC) restriction. Accordingly, the γδ T cell receptor (TCR) can potentially recognize a wide array of ligands; however, few ligands have been described to date. While there is a growing appreciation of the molecular bases underpinning variable (V)δ1+ and Vδ2+ γδ TCR-mediated ligand recognition, the mode of Vδ3+ TCR ligand engagement is unknown. MHC class I-related protein, MR1, presents vitamin B metabolites to αß T cells known as mucosal-associated invariant T cells, diverse MR1-restricted T cells, and a subset of human γδ T cells. Here, we identify Vδ1/2- γδ T cells in the blood and duodenal biopsy specimens of children that showed metabolite-independent binding of MR1 tetramers. Characterization of one Vδ3Vγ8 TCR clone showed MR1 reactivity was independent of the presented antigen. Determination of two Vδ3Vγ8 TCR-MR1-antigen complex structures revealed a recognition mechanism by the Vδ3 TCR chain that mediated specific contacts to the side of the MR1 antigen-binding groove, representing a previously uncharacterized MR1 docking topology. The binding of the Vδ3+ TCR to MR1 did not involve contacts with the presented antigen, providing a basis for understanding its inherent MR1 autoreactivity. We provide molecular insight into antigen-independent recognition of MR1 by a Vδ3+ γδ TCR that strengthens an emerging paradigm of antibody-like ligand engagement by γδ TCRs.

4.
J Biol Chem ; 297(6): 101362, 2021 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-34756886

RESUMO

The Nsp9 replicase is a conserved coronaviral protein that acts as an essential accessory component of the multi-subunit viral replication/transcription complex. Nsp9 is the predominant substrate for the essential nucleotidylation activity of Nsp12. Compounds specifically interfering with this viral activity would facilitate its study. Using a native mass-spectrometry-based approach to screen a natural product library for Nsp9 binders, we identified an ent-kaurane natural product, oridonin, capable of binding to purified SARS-CoV-2 Nsp9 with micromolar affinities. By determining the crystal structure of the Nsp9-oridonin complex, we showed that oridonin binds through a conserved site near Nsp9's C-terminal GxxxG-helix. In enzymatic assays, oridonin's binding to Nsp9 reduces its potential to act as substrate for Nsp12's Nidovirus RdRp-Associated Nucleotidyl transferase (NiRAN) domain. We also showed using in vitro cellular assays oridonin, while cytotoxic at higher doses has broad antiviral activity, reducing viral titer following infection with either SARS-CoV-2 or, to a lesser extent, MERS-CoV. Accordingly, these preliminary findings suggest that the oridonin molecular scaffold may have the potential to be developed into an antiviral compound to inhibit the function of Nsp9 during coronaviral replication.

5.
Nature ; 600(7888): 302-307, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34759313

RESUMO

Small molecules derived from symbiotic microbiota critically contribute to intestinal immune maturation and regulation1. However, little is known about the molecular mechanisms that control immune development in the host-microbiota environment. Here, using a targeted lipidomic analysis and synthetic approach, we carried out a multifaceted investigation of immunomodulatory α-galactosylceramides from the human symbiont Bacteroides fragilis (BfaGCs). The characteristic terminal branching of BfaGCs is the result of incorporation of branched-chain amino acids taken up in the host gut by B. fragilis. A B. fragilis knockout strain that cannot metabolize branched-chain amino acids showed reduced branching in BfaGCs, and mice monocolonized with this mutant strain had impaired colonic natural killer T (NKT) cell regulation, implying structure-specific immunomodulatory activity. The sphinganine chain branching of BfaGCs is a critical determinant of NKT cell activation, which induces specific immunomodulatory gene expression signatures and effector functions. Co-crystal structure and affinity analyses of CD1d-BfaGC-NKT cell receptor complexes confirmed the interaction of BfaGCs as CD1d-restricted ligands. We present a structural and molecular-level paradigm of immunomodulatory control by interactions of endobiotic metabolites with diet, microbiota and the immune system.

6.
J Infect Dis ; 2021 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-34648018

RESUMO

The antigen presentation molecule MR1 presents ligands derived from the riboflavin (vitamin B) synthesis pathway, which is not present in mammalian species or viruses, to Mucosal Associated Invariant T (MAIT) cells. In this study, we demonstrate that Varicella Zoster Virus (VZV) profoundly suppresses MR1 expression. We show that VZV targets the intracellular reservoir of immature MR1 for degradation, whilst pre-existing, ligand bound cell surface MR1 is protected from such targeting; thereby highlighting an intricate temporal relationship between infection and ligand availability. We also identify VZV open reading frame (ORF) 66 as functioning to suppress MR1 expression when this viral protein is expressed during transient transfection, but this is not apparent during infection with a VZV mutant virus lacking ORF66 expression. This indicates that VZV is likely to encode multiple viral genes that target MR1. Overall, we identify an immunomodulatory function of VZV whereby infection suppresses the MR1 biosynthesis pathway.

7.
J Biol Chem ; 297(4): 101197, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34536421

RESUMO

Whereas proteolytic cleavage is crucial for peptide presentation by classical major histocompatibility complex (MHC) proteins to T cells, glycolipids presented by CD1 molecules are typically presented in an unmodified form. However, the mycobacterial lipid antigen mannosyl-ß1-phosphomycoketide (MPM) may be processed through hydrolysis in antigen presenting cells, forming mannose and phosphomycoketide (PM). To further test the hypothesis that some lipid antigens are processed, and to generate antigens that lead to defined epitopes for future tuberculosis vaccines or diagnostic tests, we aimed to create hydrolysis-resistant MPM variants that retain their antigenicity. Here, we designed and tested three different, versatile synthetic strategies to chemically stabilize MPM analogs. Crystallographic studies of CD1c complexes with these three new MPM analogs showed anchoring of the lipid tail and phosphate group that is highly comparable to nature-identical MPM, with considerable conformational flexibility for the mannose head group. MPM-3, a difluoromethylene-modified version of MPM that is resistant to hydrolysis, showed altered recognition by cells, but not by CD1c proteins, supporting the cellular antigen processing hypothesis. Furthermore, the synthetic analogs elicited T cell responses that were cross-reactive with nature-identical MPM, fulfilling important requirements for future clinical use.


Assuntos
Antígenos de Bactérias/química , Antígenos CD1/química , Glicolipídeos/química , Glicoproteínas/química , Mycobacterium tuberculosis/química , Fosfolipídeos/química , Linfócitos T/química , Antígenos de Bactérias/imunologia , Antígenos CD1/imunologia , Linhagem Celular Transformada , Cristalografia por Raios X , Glicolipídeos/imunologia , Glicoproteínas/imunologia , Humanos , Mycobacterium tuberculosis/imunologia , Fosfolipídeos/imunologia , Linfócitos T/imunologia
8.
Biochem Soc Trans ; 49(5): 1985-1995, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34515758

RESUMO

The γδ T cell immune cell lineage has remained relatively enigmatic and under-characterised since their identification. Conversely, the insights we have, highlight their central importance in diverse immunological roles and homeostasis. Thus, γδ T cells are considered as potentially a new translational tool in the design of new therapeutics for cancer and infectious disease. Here we review our current understanding of γδ T cell biology viewed through a structural lens centred on the how the γδ T cell receptor mediates ligand recognition. We discuss the limited knowledge of antigens, the structural basis of such reactivities and discuss the emerging trends of γδ T cell reactivity and implications for γδ T cell biology.

9.
J Immunol ; 207(7): 1836-1847, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34479944

RESUMO

DEC-205 is a cell-surface receptor that transports bound ligands into the endocytic pathway for degradation or release within lysosomal endosomes. This receptor has been reported to bind a number of ligands, including keratin, and some classes of CpG oligodeoxynucleotides (ODN). In this study, we explore in detail the requirements for binding ODNs, revealing that DEC-205 efficiently binds single-stranded, phosphorothioated ODN of ≥14 bases, with preference for the DNA base thymidine, but with no requirement for a CpG motif. DEC-205 fails to bind double-stranded phosphodiester ODN, and thus does not bind the natural type of DNA found in mammals. The ODN binding preferences of DEC-205 result in strong binding of B class ODN, moderate binding to C class ODN, minimal binding to P class ODN, and no binding to A class ODN. Consistent with DEC-205 binding capacity, induction of serum IL-12p70 or activation of B cells by each class of ODN correlated with DEC-205 dependence in mice. Thus, the greater the DEC-205 binding capacity, the greater the dependence on DEC-205 for optimal responses. Finally, by covalently linking a B class ODN that efficiently binds DEC-205, to a P class ODN that shows poor binding, we improved DEC-205 binding and increased adjuvancy of the hybrid ODN. The hybrid ODN efficiently enhanced induction of effector CD8 T cells in a DEC-205-dependent manner. Furthermore, the hybrid ODN induced robust memory responses, and was particularly effective at promoting the development of liver tissue-resident memory T cells.


Assuntos
Adjuvantes Imunológicos , Oligodesoxirribonucleotídeos , Animais , Células Dendríticas , Interleucina-12 , Fígado , Camundongos
10.
J Biol Chem ; 297(3): 101065, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34384783

RESUMO

CD8+ T cells play an important role in vaccination and immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Although numerous SARS-CoV-2 CD8+ T cell epitopes have been identified, the molecular basis underpinning T cell receptor (TCR) recognition of SARS-CoV-2-specific T cells remains unknown. The T cell response directed toward SARS-CoV-2 spike protein-derived S269-277 peptide presented by the human leukocyte antigen (HLA)-A∗02:01 allomorph (hereafter the HLA-A2S269-277 epitope) is, to date, the most immunodominant SARS-CoV-2 epitope found in individuals bearing this allele. As HLA-A2S269-277-specific CD8+ T cells utilize biased TRAV12 gene usage within the TCR α-chain, we sought to understand the molecular basis underpinning this TRAV12 dominance. We expressed four TRAV12+ TCRs which bound the HLA-A2S269-277 complex with low micromolar affinity and determined the crystal structure of the HLA-A2S269-277 binary complex, and subsequently a ternary structure of the TRAV12+ TCR complexed to HLA-A2S269-277. We found that the TCR made extensive contacts along the entire length of the S269-277 peptide, suggesting that the TRAV12+ TCRs would be sensitive to sequence variation within this epitope. To examine this, we investigated cross-reactivity toward analogous peptides from existing SARS-CoV-2 variants and closely related coronaviruses. We show via surface plasmon resonance and tetramer studies that the TRAV12+ T cell repertoire cross-reacts poorly with these analogous epitopes. Overall, we defined the structural basis underpinning biased TCR recognition of CD8+ T cells directed at an immunodominant epitope and provide a framework for understanding TCR cross-reactivity toward viral variants within the S269-277 peptide.


Assuntos
Epitopos de Linfócito T/química , Antígeno HLA-A2/metabolismo , Epitopos Imunodominantes/metabolismo , Receptores de Antígenos de Linfócitos T/metabolismo , Glicoproteína da Espícula de Coronavírus/metabolismo , Humanos , Conformação Proteica , Receptores de Antígenos de Linfócitos T/química
11.
Nat Commun ; 12(1): 5110, 2021 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-34433824

RESUMO

HLA-DQ8, a genetic risk factor in type I diabetes (T1D), presents hybrid insulin peptides (HIPs) to autoreactive CD4+ T cells. The abundance of spliced peptides binding to HLA-DQ8 and how they are subsequently recognised by the autoreactive T cell repertoire is unknown. Here we report, the HIP (GQVELGGGNAVEVLK), derived from splicing of insulin and islet amyloid polypeptides, generates a preferred peptide-binding motif for HLA-DQ8. HLA-DQ8-HIP tetramer+ T cells from the peripheral blood of a T1D patient are characterised by repeated TRBV5 usage, which matches the TCR bias of CD4+ T cells reactive to the HIP peptide isolated from the pancreatic islets of a patient with T1D. The crystal structure of three TRBV5+ TCR-HLA-DQ8-HIP complexes shows that the TRBV5-encoded TCR ß-chain forms a common landing pad on the HLA-DQ8 molecule. The N- and C-termini of the HIP is recognised predominantly by the TCR α-chain and TCR ß-chain, respectively, in all three TCR ternary complexes. Accordingly, TRBV5 + TCR recognition of HIP peptides might occur via a 'polarised' mechanism, whereby each chain within the αßTCR heterodimer recognises distinct origins of the spliced peptide presented by HLA-DQ8.


Assuntos
Diabetes Mellitus Tipo 1/metabolismo , Antígenos HLA-DQ/metabolismo , Insulina/metabolismo , Peptídeos/metabolismo , Receptores de Antígenos de Linfócitos T/metabolismo , Sequência de Aminoácidos , Linfócitos T CD4-Positivos/química , Linfócitos T CD4-Positivos/metabolismo , Diabetes Mellitus Tipo 1/genética , Antígenos HLA-DQ/química , Antígenos HLA-DQ/genética , Humanos , Insulina/química , Insulina/genética , Peptídeos/química , Ligação Proteica , Receptores de Antígenos de Linfócitos T/química , Receptores de Antígenos de Linfócitos T/genética
12.
Sci Immunol ; 6(62)2021 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-34417258

RESUMO

Antibodies specific for peptides bound to human leukocyte antigen (HLA) molecules are valuable tools for studies of antigen presentation and may have therapeutic potential. Here, we generated human T cell receptor (TCR)-like antibodies toward the immunodominant signature gluten epitope DQ2.5-glia-α2 in celiac disease (CeD). Phage display selection combined with secondary targeted engineering was used to obtain highly specific antibodies with picomolar affinity. The crystal structure of a Fab fragment of the lead antibody 3.C11 in complex with HLA-DQ2.5:DQ2.5-glia-α2 revealed a binding geometry and interaction mode highly similar to prototypic TCRs specific for the same complex. Assessment of CeD biopsy material confirmed disease specificity and reinforced the notion that abundant plasma cells present antigen in the inflamed CeD gut. Furthermore, 3.C11 specifically inhibited activation and proliferation of gluten-specific CD4+ T cells in vitro and in HLA-DQ2.5 humanized mice, suggesting a potential for targeted intervention without compromising systemic immunity.

13.
Proc Natl Acad Sci U S A ; 118(34)2021 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-34417291

RESUMO

Natural killer T (NKT) cells detect lipids presented by CD1d. Most studies focus on type I NKT cells that express semi-invariant αß T cell receptors (TCR) and recognize α-galactosylceramides. However, CD1d also presents structurally distinct lipids to NKT cells expressing diverse TCRs (type II NKT cells), but our knowledge of the antigens for type II NKT cells is limited. An early study identified a nonlipidic NKT cell agonist, phenyl pentamethyldihydrobenzofuransulfonate (PPBF), which is notable for its similarity to common sulfa drugs, but its mechanism of NKT cell activation remained unknown. Here, we demonstrate that a range of pentamethylbenzofuransulfonates (PBFs), including PPBF, activate polyclonal type II NKT cells from human donors. Whereas these sulfa drug-like molecules might have acted pharmacologically on cells, here we demonstrate direct contact between TCRs and PBF-treated CD1d complexes. Further, PBF-treated CD1d tetramers identified type II NKT cell populations expressing αßTCRs and γδTCRs, including those with variable and joining region gene usage (TRAV12-1-TRAJ6) that was conserved across donors. By trapping a CD1d-type II NKT TCR complex for direct mass-spectrometric analysis, we detected molecules that allow the binding of CD1d to TCRs, finding that both selected PBF family members and short-chain sphingomyelin lipids are present in these complexes. Furthermore, the combination of PPBF and short-chain sphingomyelin enhances CD1d tetramer staining of PPBF-reactive T cell lines over either molecule alone. This study demonstrates that nonlipidic small molecules, which resemble sulfa drugs implicated in systemic hypersensitivity and drug allergy reactions, are targeted by a polyclonal population of type II NKT cells in a CD1d-restricted manner.

14.
Nat Commun ; 12(1): 4355, 2021 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-34272362

RESUMO

Mucosal-associated Invariant T (MAIT) cells are recognized for their antibacterial functions. The protective capacity of MAIT cells has been demonstrated in murine models of local infection, including in the lungs. Here we show that during systemic infection of mice with Francisella tularensis live vaccine strain results in evident MAIT cell expansion in the liver, lungs, kidney and spleen and peripheral blood. The responding MAIT cells manifest a polarised Th1-like MAIT-1 phenotype, including transcription factor and cytokine profile, and confer a critical role in controlling bacterial load. Post resolution of the primary infection, the expanded MAIT cells form stable memory-like MAIT-1 cell populations, suggesting a basis for vaccination. Indeed, a systemic vaccination with synthetic antigen 5-(2-oxopropylideneamino)-6-D-ribitylaminouracil in combination with CpG adjuvant similarly boosts MAIT cells, and results in enhanced protection against both systemic and local infections with different bacteria. Our study highlights the potential utility of targeting MAIT cells to combat a range of bacterial pathogens.


Assuntos
Citocinas/metabolismo , Francisella tularensis/imunologia , Imunidade Inata , Células T Invariantes Associadas à Mucosa/imunologia , Adjuvantes Imunológicos , Animais , Antígenos de Histocompatibilidade Classe I/genética , Antígenos de Histocompatibilidade Classe I/imunologia , Fígado/imunologia , Pulmão/imunologia , Camundongos , Camundongos Knockout , Antígenos de Histocompatibilidade Menor/genética , Antígenos de Histocompatibilidade Menor/imunologia , Células T Invariantes Associadas à Mucosa/metabolismo , Fenótipo , RNA-Seq , Ribitol/análogos & derivados , Ribitol/imunologia , Análise de Célula Única , Baço/imunologia , Células Th1/imunologia , Células Th1/metabolismo , Transcriptoma/genética , Uracila/análogos & derivados , Uracila/imunologia , Vacinas Atenuadas/imunologia
15.
Nature ; 595(7868): 501-510, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34290426

RESUMO

The unconventional T cell compartment encompasses a variety of cell subsets that straddle the line between innate and adaptive immunity, often reside at mucosal surfaces and can recognize a wide range of non-polymorphic ligands. Recent advances have highlighted the role of unconventional T cells in tissue homeostasis and disease. In this Review, we recast unconventional T cell subsets according to the class of ligand that they recognize; their expression of semi-invariant or diverse T cell receptors; the structural features that underlie ligand recognition; their acquisition of effector functions in the thymus or periphery; and their distinct functional properties. Unconventional T cells follow specific selection rules and are poised to recognize self or evolutionarily conserved microbial antigens. We discuss these features from an evolutionary perspective to provide insights into the development and function of unconventional T cells. Finally, we elaborate on the functional redundancy of unconventional T cells and their relationship to subsets of innate and adaptive lymphoid cells, and propose that the unconventional T cell compartment has a critical role in our survival by expanding and complementing the role of the conventional T cell compartment in protective immunity, tissue healing and barrier function.

16.
J Biol Chem ; 297(3): 101018, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34331944

RESUMO

The coronaviral nonstructural protein 9 (Nsp9) is essential for viral replication; it is the primary substrate of Nsp12's pseudokinase domain within the viral replication transcription complex, an association that also recruits other components during different stages of RNA reproduction. In the unmodified state, Nsp9 forms an obligate homodimer via an essential GxxxG protein-interaction motif, but its ssRNA-binding mechanism remains unknown. Using structural biological techniques, here we show that a base-mimicking compound identified from a small molecule fragment screen engages Nsp9 via a tetrameric Pi-Pi stacking interaction that induces the formation of a parallel trimer-of-dimers. This oligomerization mechanism allows an interchange of "latching" N-termini, the charges of which contribute to a series of electropositive channels that suggests a potential interface for viral RNA. The identified pyrrolo-pyrimidine compound may also serve as a potential starting point for the development of compounds seeking to probe Nsp9's role within SARS-CoV-2 replication.


Assuntos
COVID-19/virologia , Nucleotídeos de Pirimidina/metabolismo , Proteínas de Ligação a RNA/metabolismo , SARS-CoV-2/metabolismo , Proteínas Virais/metabolismo , Ressonância Magnética Nuclear Biomolecular/métodos , Ligação Proteica , RNA/metabolismo , SARS-CoV-2/fisiologia , Replicação Viral
17.
Science ; 372(6546)2021 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-34083463

RESUMO

T cell receptor (TCR) recognition of peptide-major histocompatibility complexes (pMHCs) is characterized by a highly conserved docking polarity. Whether this polarity is driven by recognition or signaling constraints remains unclear. Using "reversed-docking" TCRß-variable (TRBV) 17+ TCRs from the naïve mouse CD8+ T cell repertoire that recognizes the H-2Db-NP366 epitope, we demonstrate that their inability to support T cell activation and in vivo recruitment is a direct consequence of reversed docking polarity and not TCR-pMHCI binding or clustering characteristics. Canonical TCR-pMHCI docking optimally localizes CD8/Lck to the CD3 complex, which is prevented by reversed TCR-pMHCI polarity. The requirement for canonical docking was circumvented by dissociating Lck from CD8. Thus, the consensus TCR-pMHC docking topology is mandated by T cell signaling constraints.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Antígeno de Histocompatibilidade H-2D/metabolismo , Proteínas do Nucleocapsídeo/metabolismo , Infecções por Orthomyxoviridae/imunologia , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Animais , Complexo CD3/metabolismo , Antígenos CD8/imunologia , Antígenos CD8/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Epitopos de Linfócito T , Feminino , Antígeno de Histocompatibilidade H-2D/química , Antígeno de Histocompatibilidade H-2D/imunologia , Vírus da Influenza A , Ativação Linfocitária , Proteína Tirosina Quinase p56(lck) Linfócito-Específica/metabolismo , Complexo Principal de Histocompatibilidade , Camundongos , Camundongos Endogâmicos C57BL , Modelos Moleculares , Proteínas do Nucleocapsídeo/química , Proteínas do Nucleocapsídeo/imunologia , Fragmentos de Peptídeos/imunologia , Fragmentos de Peptídeos/metabolismo , Ligação Proteica , Conformação Proteica , Receptores de Antígenos de Linfócitos T alfa-beta/química , Receptores de Antígenos de Linfócitos T alfa-beta/imunologia , Transdução de Sinais
18.
Immunol Cell Biol ; 99(9): 990-1000, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34086357

RESUMO

In-depth understanding of human T-cell-mediated immunity in coronavirus disease 2019 (COVID-19) is needed if we are to optimize vaccine strategies and immunotherapies. Identification of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) T-cell epitopes and generation of peptide-human leukocyte antigen (peptide-HLA) tetramers facilitate direct ex vivo analyses of SARS-CoV-2-specific T cells and their T-cell receptor (TCR) repertoires. We utilized a combination of peptide prediction and in vitro peptide stimulation to validate novel SARS-CoV-2 epitopes restricted by HLA-A*24:02, one of the most prominent HLA class I alleles, especially in Indigenous and Asian populations. Of the peptides screened, three spike-derived peptides generated CD8+ IFNγ+ responses above background, S1208-1216 (QYIKWPWYI), S448-456 (NYNYLYRLF) and S193-201 (VFKNIDGYF), with S1208 generating immunodominant CD8+ IFNγ+ responses. Using peptide-HLA-I tetramers, we performed direct ex vivo tetramer enrichment for HLA-A*24:02-restricted CD8+ T cells in COVID-19 patients and prepandemic controls. The precursor frequencies for HLA-A*24:02-restricted epitopes were within the range previously observed for other SARS-CoV-2 epitopes for both COVID-19 patients and prepandemic individuals. Naïve A24/SARS-CoV-2-specific CD8+ T cells increased nearly 7.5-fold above the average precursor frequency during COVID-19, gaining effector and memory phenotypes. Ex vivo single-cell analyses of TCRαß repertoires found that the A24/S448 + CD8+ T-cell TCRαß repertoire was driven by a common TCRß chain motif, whereas the A24/S1208 + CD8+ TCRαß repertoire was diverse across COVID-19 patients. Our study provides an in depth characterization and important insights into SARS-CoV-2-specific CD8+ T-cell responses associated with a prominent HLA-A*24:02 allomorph. This contributes to our knowledge on adaptive immune responses during primary COVID-19 and could be exploited in vaccine or immunotherapeutic approaches.


Assuntos
Linfócitos T CD8-Positivos/imunologia , COVID-19 , Antígeno HLA-A24 , Receptores de Antígenos de Linfócitos T/imunologia , COVID-19/imunologia , Humanos , SARS-CoV-2
19.
Nat Commun ; 12(1): 2691, 2021 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-33976217

RESUMO

How innate and adaptive immune responses work in concert to resolve influenza disease is yet to be fully investigated in one single study. Here, we utilize longitudinal samples from patients hospitalized with acute influenza to understand these immune responses. We report the dynamics of 18 important immune parameters, related to clinical, genetic and virological factors, in influenza patients across different severity levels. Influenza disease correlates with increases in IL-6/IL-8/MIP-1α/ß cytokines and lower antibody responses. Robust activation of circulating T follicular helper cells correlates with peak antibody-secreting cells and influenza heamaglutinin-specific memory B-cell numbers, which phenotypically differs from vaccination-induced B-cell responses. Numbers of influenza-specific CD8+ or CD4+ T cells increase early in disease and retain an activated phenotype during patient recovery. We report the characterisation of immune cellular networks underlying recovery from influenza infection which are highly relevant to other infectious diseases.


Assuntos
Formação de Anticorpos/imunologia , Linfócitos B/imunologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Citocinas/imunologia , Influenza Humana/imunologia , Linfócitos T Auxiliares-Indutores/imunologia , Estudos de Coortes , Citocinas/metabolismo , Hospitalização/estatística & dados numéricos , Humanos , Vírus da Influenza A/classificação , Vírus da Influenza A/genética , Vírus da Influenza A/fisiologia , Vacinas contra Influenza/imunologia , Influenza Humana/virologia , Pessoa de Meia-Idade , Filogenia , Vacinação/métodos
20.
Nat Commun ; 12(1): 2931, 2021 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-34006841

RESUMO

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/PB2550-558-specific CD8+ T cells being cross-reactive between IAV and IBV. Memory CD8+ T cells towards these specificities are present in blood (CD27+CD45RA- phenotype) and tissues (CD103+CD69+ phenotype) of healthy individuals, and effector CD27-CD45RA-PD-1+CD38+CD8+ 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.


Assuntos
Linfócitos T CD8-Positivos/metabolismo , Epitopos de Linfócito T/genética , Antígeno HLA-A24/genética , Povos Indígenas/genética , Adulto , Alelos , Sequência de Aminoácidos , Animais , Austrália , Linfócitos T CD8-Positivos/imunologia , Células Cultivadas , Cães , Epitopos de Linfócito T/imunologia , Feminino , Frequência do Gene , Antígeno HLA-A24/imunologia , Humanos , Vírus da Influenza A/imunologia , Vírus da Influenza A/fisiologia , Vírus da Influenza B/imunologia , Vírus da Influenza B/fisiologia , Influenza Humana/imunologia , Influenza Humana/virologia , Masculino , Camundongos Transgênicos , Pessoa de Meia-Idade
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