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1.
Adv Exp Med Biol ; 1255: 29-50, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32949388

RESUMO

T cells recognize peptides bound to major histocompatibility complex (MHC) class I and class II molecules at the cell surface. This recognition is accomplished by the expression of T cell receptors (TCR) which are required to be diverse and adaptable in order to accommodate the various and vast number of antigens presented on the MHCs. Thus, determining TCR repertoires of effector T cells is necessary to understand the immunological process in responding to cancer progression, infection, and autoimmune development. Furthermore, understanding the TCR repertoires will provide a solid framework to predict and test the antigen which is more critical in autoimmunity. However, it has been a technical challenge to sequence the TCRs and provide a conceptual context in correlation to the vast number of TCR repertoires in the immunological system. The exploding field of single-cell sequencing has changed how the repertoires are being investigated and analyzed. In this review, we focus on the biology of TCRs, TCR signaling and its implication in autoimmunity. We discuss important methods in bulk sequencing of many cells. Lastly, we explore the most pertinent platforms in single-cell sequencing and its application in autoimmunity.


Assuntos
Receptores de Antígenos de Linfócitos T/genética , Análise de Sequência , Análise de Célula Única , Animais , Autoimunidade/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Humanos , Receptores de Antígenos de Linfócitos T/imunologia , Linfócitos T/imunologia , Linfócitos T/metabolismo
2.
Nat Commun ; 11(1): 4454, 2020 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-32901001

RESUMO

Chronic viral infections are often associated with impaired CD8+ T cell function, referred to as exhaustion. Although the molecular and cellular circuits involved in CD8+ T cell exhaustion are well defined, with sustained presence of antigen being one important parameter, how much T cell receptor (TCR) signaling is actually ongoing in vivo during established chronic infection is unclear. Here, we characterize the in vivo TCR signaling of virus-specific exhausted CD8+ T cells in a mouse model, leveraging TCR signaling reporter mice in combination with transcriptomics. In vivo signaling in exhausted cells is low, in contrast to their in vitro signaling potential, and despite antigen being abundantly present. Both checkpoint blockade and adoptive transfer of naïve target cells increase TCR signaling, demonstrating that engagement of co-inhibitory receptors curtails CD8+ T cell signaling and function in vivo.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Coriomeningite Linfocítica/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Transferência Adotiva , Animais , Antígeno B7-H1/antagonistas & inibidores , Antígeno B7-H1/imunologia , Linfócitos T CD8-Positivos/virologia , Doença Crônica , Citotoxicidade Imunológica , Modelos Animais de Doenças , Regulação para Baixo , Tolerância Imunológica , Imunidade Celular , Técnicas In Vitro , Ativação Linfocitária , Coriomeningite Linfocítica/genética , Vírus da Coriomeningite Linfocítica/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/genética , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/imunologia , Receptor de Morte Celular Programada 1/imunologia , RNA-Seq , Transdução de Sinais/imunologia
4.
Signal Transduct Target Ther ; 5(1): 156, 2020 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-32796814

RESUMO

The global Coronavirus disease 2019 (COVID-19) pandemic caused by SARS-CoV-2 has affected more than eight million people. There is an urgent need to investigate how the adaptive immunity is established in COVID-19 patients. In this study, we profiled adaptive immune cells of PBMCs from recovered COVID-19 patients with varying disease severity using single-cell RNA and TCR/BCR V(D)J sequencing. The sequencing data revealed SARS-CoV-2-specific shuffling of adaptive immune repertories and COVID-19-induced remodeling of peripheral lymphocytes. Characterization of variations in the peripheral T and B cells from the COVID-19 patients revealed a positive correlation of humoral immune response and T-cell immune memory with disease severity. Sequencing and functional data revealed SARS-CoV-2-specific T-cell immune memory in the convalescent COVID-19 patients. Furthermore, we also identified novel antigens that are responsive in the convalescent patients. Altogether, our study reveals adaptive immune repertories underlying pathogenesis and recovery in severe versus mild COVID-19 patients, providing valuable information for potential vaccine and therapeutic development against SARS-CoV-2 infection.


Assuntos
Linfócitos B/imunologia , Betacoronavirus/patogenicidade , Infecções por Coronavirus/imunologia , Imunidade Celular , Imunidade Humoral , Pneumonia Viral/imunologia , Linfócitos T/imunologia , Antígenos Virais/genética , Antígenos Virais/imunologia , Linfócitos B/classificação , Linfócitos B/virologia , Betacoronavirus/imunologia , Estudos de Casos e Controles , China , Convalescença , Infecções por Coronavirus/genética , Infecções por Coronavirus/patologia , Infecções por Coronavirus/virologia , Progressão da Doença , Expressão Gênica , Sequenciamento de Nucleotídeos em Larga Escala , Interações Hospedeiro-Patógeno/imunologia , Humanos , Memória Imunológica , Pandemias , Pneumonia Viral/genética , Pneumonia Viral/patologia , Pneumonia Viral/virologia , Receptores de Antígenos de Linfócitos B/classificação , Receptores de Antígenos de Linfócitos B/genética , Receptores de Antígenos de Linfócitos B/imunologia , Receptores de Antígenos de Linfócitos T/classificação , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/imunologia , Índice de Gravidade de Doença , Análise de Célula Única , Linfócitos T/classificação , Linfócitos T/virologia
5.
Nat Commun ; 11(1): 4166, 2020 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-32820173

RESUMO

T cells engineered to express chimeric antigen receptors (CAR-T cells) have shown impressive clinical efficacy in the treatment of B cell malignancies. However, the development of CAR-T cell therapies for solid tumors is hampered by the lack of truly tumor-specific antigens and poor control over T cell activity. Here we present an avidity-controlled CAR (AvidCAR) platform with inducible and logic control functions. The key is the combination of (i) an improved CAR design which enables controlled CAR dimerization and (ii) a significant reduction of antigen-binding affinities to introduce dependence on bivalent interaction, i.e. avidity. The potential and versatility of the AvidCAR platform is exemplified by designing ON-switch CARs, which can be regulated with a clinically applied drug, and AND-gate CARs specifically recognizing combinations of two antigens. Thus, we expect that AvidCARs will be a highly valuable platform for the development of controllable CAR therapies with improved tumor specificity.


Assuntos
Imunoterapia Adotiva/métodos , Receptores de Antígenos de Linfócitos T/imunologia , Receptores de Antígenos Quiméricos/imunologia , Linfócitos T/imunologia , Animais , Antígenos de Neoplasias/imunologia , Linfócitos B/imunologia , Linfócitos B/metabolismo , Células Cultivadas , Citocinas/imunologia , Citocinas/metabolismo , Citotoxicidade Imunológica/imunologia , Humanos , Ativação Linfocitária/imunologia , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos SCID , Neoplasias/imunologia , Neoplasias/patologia , Neoplasias/terapia , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/metabolismo , Receptores de Antígenos Quiméricos/genética , Receptores de Antígenos Quiméricos/metabolismo , Linfócitos T/metabolismo
6.
PLoS Comput Biol ; 16(8): e1007910, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32841238

RESUMO

Phenotypic variation in the copy number of gene products expressed by cells or tissues has been the focus of intense investigation. To what extent the observed differences in cellular expression levels are persistent or transient is an intriguing question. Here, we develop a quantitative framework that resolves the expression variation into stable and unstable components. The difference between the expression means in two cohorts isolated from any cell population is shown to converge to an asymptotic value, with a characteristic time, τT, that measures the timescale of the unstable dynamics. The asymptotic difference in the means, relative to the initial value, measures the stable proportion of the original population variance [Formula: see text]. Empowered by this insight, we analysed the T-cell receptor (TCR) expression variation in CD4 T cells. About 70% of TCR expression variance is stable in a diverse polyclonal population, while over 80% of the variance in an isogenic TCR transgenic population is volatile. In both populations the TCR levels fluctuate with a characteristic time of 32 hours. This systematic characterisation of the expression variation dynamics, relying on time series of cohorts' means, can be combined with technologies that measure gene or protein expression in single cells or in bulk.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Animais , Separação Celular , Citometria de Fluxo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos
7.
Signal Transduct Target Ther ; 5(1): 156, 2020 08 14.
Artigo em Inglês | MEDLINE | ID: covidwho-717099

RESUMO

The global Coronavirus disease 2019 (COVID-19) pandemic caused by SARS-CoV-2 has affected more than eight million people. There is an urgent need to investigate how the adaptive immunity is established in COVID-19 patients. In this study, we profiled adaptive immune cells of PBMCs from recovered COVID-19 patients with varying disease severity using single-cell RNA and TCR/BCR V(D)J sequencing. The sequencing data revealed SARS-CoV-2-specific shuffling of adaptive immune repertories and COVID-19-induced remodeling of peripheral lymphocytes. Characterization of variations in the peripheral T and B cells from the COVID-19 patients revealed a positive correlation of humoral immune response and T-cell immune memory with disease severity. Sequencing and functional data revealed SARS-CoV-2-specific T-cell immune memory in the convalescent COVID-19 patients. Furthermore, we also identified novel antigens that are responsive in the convalescent patients. Altogether, our study reveals adaptive immune repertories underlying pathogenesis and recovery in severe versus mild COVID-19 patients, providing valuable information for potential vaccine and therapeutic development against SARS-CoV-2 infection.


Assuntos
Linfócitos B/imunologia , Betacoronavirus/patogenicidade , Infecções por Coronavirus/imunologia , Imunidade Celular , Imunidade Humoral , Pneumonia Viral/imunologia , Linfócitos T/imunologia , Antígenos Virais/genética , Antígenos Virais/imunologia , Linfócitos B/classificação , Linfócitos B/virologia , Betacoronavirus/imunologia , Estudos de Casos e Controles , China , Convalescença , Infecções por Coronavirus/genética , Infecções por Coronavirus/patologia , Infecções por Coronavirus/virologia , Progressão da Doença , Expressão Gênica , Sequenciamento de Nucleotídeos em Larga Escala , Interações Hospedeiro-Patógeno/imunologia , Humanos , Memória Imunológica , Pandemias , Pneumonia Viral/genética , Pneumonia Viral/patologia , Pneumonia Viral/virologia , Receptores de Antígenos de Linfócitos B/classificação , Receptores de Antígenos de Linfócitos B/genética , Receptores de Antígenos de Linfócitos B/imunologia , Receptores de Antígenos de Linfócitos T/classificação , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/imunologia , Índice de Gravidade de Doença , Análise de Célula Única , Linfócitos T/classificação , Linfócitos T/virologia
8.
Curr Res Transl Med ; 68(3): 111-118, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32620465

RESUMO

The pandemic of coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is spreading rapidly across the world. Currently, the COVID-19 pandemic is affecting the continuity of essential routine healthcare services and procedures, including chimeric antigen receptor T-cell (CAR-T) therapy, a life-saving option for patients with relapsed/refractory (R/R) hematologic malignancies. Due to the rapid disease progression of hematological malignancies, there is an urgent need to manufacture and utilize CAR T-cells. However, CAR-T treatment has become extraordinarily challenging during this COVID-19 pandemic. Thus, many medical and technical factors must now be taken into consideration before, during, and after CAR-T therapy. The purpose of this review is to provide brief suggestions for rational decision-making strategies in evaluating and selecting CAR T-cell treatment and appropriate CAR T-cell products, and protective strategies for medical staff and patients to prevent infection in the midst of the current COVID-19 pandemic.


Assuntos
Infecções por Coronavirus/prevenção & controle , Assistência à Saúde/organização & administração , Neoplasias Hematológicas/terapia , Imunoterapia Adotiva , Controle de Infecções/organização & administração , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Receptores de Antígenos de Linfócitos T/imunologia , Betacoronavirus/fisiologia , Infecções por Coronavirus/epidemiologia , Assistência à Saúde/métodos , Assistência à Saúde/normas , Assistência à Saúde/tendências , Neoplasias Hematológicas/epidemiologia , Humanos , Imunoterapia Adotiva/métodos , Imunoterapia Adotiva/tendências , Controle de Infecções/métodos , Controle de Infecções/normas , Controle de Infecções/tendências , Pneumonia Viral/epidemiologia , Serviços Preventivos de Saúde/métodos , Serviços Preventivos de Saúde/organização & administração , Serviços Preventivos de Saúde/normas , Serviços Preventivos de Saúde/tendências
9.
Curr Res Transl Med ; 68(3): 111-118, 2020 08.
Artigo em Inglês | MEDLINE | ID: covidwho-622221

RESUMO

The pandemic of coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is spreading rapidly across the world. Currently, the COVID-19 pandemic is affecting the continuity of essential routine healthcare services and procedures, including chimeric antigen receptor T-cell (CAR-T) therapy, a life-saving option for patients with relapsed/refractory (R/R) hematologic malignancies. Due to the rapid disease progression of hematological malignancies, there is an urgent need to manufacture and utilize CAR T-cells. However, CAR-T treatment has become extraordinarily challenging during this COVID-19 pandemic. Thus, many medical and technical factors must now be taken into consideration before, during, and after CAR-T therapy. The purpose of this review is to provide brief suggestions for rational decision-making strategies in evaluating and selecting CAR T-cell treatment and appropriate CAR T-cell products, and protective strategies for medical staff and patients to prevent infection in the midst of the current COVID-19 pandemic.


Assuntos
Infecções por Coronavirus/prevenção & controle , Assistência à Saúde/organização & administração , Neoplasias Hematológicas/terapia , Imunoterapia Adotiva , Controle de Infecções/organização & administração , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Receptores de Antígenos de Linfócitos T/imunologia , Betacoronavirus/fisiologia , Infecções por Coronavirus/epidemiologia , Assistência à Saúde/métodos , Assistência à Saúde/normas , Assistência à Saúde/tendências , Neoplasias Hematológicas/epidemiologia , Humanos , Imunoterapia Adotiva/métodos , Imunoterapia Adotiva/tendências , Controle de Infecções/métodos , Controle de Infecções/normas , Controle de Infecções/tendências , Pneumonia Viral/epidemiologia , Serviços Preventivos de Saúde/métodos , Serviços Preventivos de Saúde/organização & administração , Serviços Preventivos de Saúde/normas , Serviços Preventivos de Saúde/tendências
10.
Mol Immunol ; 125: 43-50, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32645549

RESUMO

The CD8 T cell response to the HLA-A2-restricted epitope LLWNGPMAV (LLW) of the non-structural protein 4b of Yellow Fever Virus (YFV) is remarkably immunodominant, highly prevalent and powerful in YFV-vaccinated humans. Here we used a combinatorial peptide library screening in the context of an A2/LLW-specific CD8 T cell clone to identify a superagonist that features a methionine to isoleucine substitution at position 7. Based on in silico modeling, the functional enhancement of this LLW-7I mutation was associated with alterations in the structural dynamics of the peptide in the major histocompatibility complex (pMHC) binding with the T cell receptor (TCR). While the TCR off-rate of LLW-7I pMHC is comparable to the wild type peptide, the rigidity of the 7I peptide seems to confer less entropy loss upon TCR binding. This LLW-7I superagonist is an example of improved functionality in human CD8 T cells associated with optimized ligand rigidity for TCR binding and not with changes in TCR:pMHC off-rate kinetics.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Epitopos Imunodominantes/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Proteínas não Estruturais Virais/imunologia , Vírus da Febre Amarela/imunologia , Epitopos de Linfócito T/química , Epitopos de Linfócito T/imunologia , Antígeno HLA-A2/química , Antígeno HLA-A2/imunologia , Humanos , Epitopos Imunodominantes/química , Modelos Moleculares , Mutação , Biblioteca de Peptídeos , Ligação Proteica/imunologia , Receptores de Antígenos de Linfócitos T/química
11.
Scand J Immunol ; 92(4): e12927, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32640053

RESUMO

Malignant melanoma has seen monumental changes in treatment options the last decade from the very poor results of dacarbazine treatment to the modern-day use of targeted therapies and immune checkpoint inhibitors. Melanoma has a high mutational burden making it more capable of evoking immune responses than many other tumours. Even when considering double immune checkpoint blockade with anti-CTLA-4 and anti-PD-1, we still have far to go in melanoma treatment as 50% of patients with metastatic disease do not respond to current treatment. Alternative immunotherapy should therefore be considered. Since melanoma has a high mutational burden, it is considered more immunogenic than many other tumours. T cell receptor (TCR) therapy could be a possible way forward, either alone or in combination, to improve the response rates of this deadly disease. Melanoma is one of the cancers where TCR therapy has been frequently applied. However, the number of antigens targeted remains fairly limited, although advanced personalized therapies aim at also targeting private mutations. In this review, we look at possible aspects of targeting TCR therapy towards melanoma and provide an implication of its use in the future.


Assuntos
Imunoterapia/métodos , Melanoma/imunologia , Melanoma/terapia , Receptores de Antígenos de Linfócitos T/imunologia , Neoplasias Cutâneas/imunologia , Neoplasias Cutâneas/terapia , Animais , Humanos
12.
Mol Immunol ; 124: 125-141, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32563081

RESUMO

Both mouse and human harbour memory phenotype CD8+ T cells specific for antigens in hosts that have not been previously exposed to these antigens. The origin and the nature of the stimuli responsible for generation of CD44hi CD8+ T cells in specific pathogen-free (SPF) mice remain controversial. It is known that microbiota plays a crucial role in the prevention and resolution of systemic infections by influencing myelopoiesis, regulating dendritic cells, inflammasome activation and promoting the production of type I and II interferons. By contrast, here we suggest that microbiota has a direct effect on generation of memory phenotype CD44hiGP33+CD8+ T cells. In SPF mice, it generates a novel GP33+CD44hiCD8+ T cell sub-population associating the properties of innate and genuine memory cells. These cells are highly enriched in the bone marrow, proliferate rapidly and express immediate effector functions. They dominate the response to LCMV and express particular TCRß chains. The sequence of these selected TCRß chains overlaps with that of GP33+CD8+ T cells directly selected by microbiota in the gut epithelium of SPF mice, demonstrating a common selection mechanism in gut and peripheral CD8+ T cell pool. Therefore microbiota has a direct role in priming T cell immunity in SPF mice and in the selection of TCRß repertoires during systemic infection. We identify a mechanism that primes T cell immunity in SPF mice and may have a major role in colonization resistance and protection from infection.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Coriomeningite Linfocítica/imunologia , Microbiota/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Animais , Citotoxicidade Imunológica/imunologia , Memória Imunológica/imunologia , Vírus da Coriomeningite Linfocítica/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Organismos Livres de Patógenos Específicos , Subpopulações de Linfócitos T/imunologia
13.
Trends Pharmacol Sci ; 41(8): 518-530, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32576386

RESUMO

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected several millions and killed more than quarter of a million worldwide to date. Important questions have remained unanswered: why some patients develop severe disease, while others do not; and what roles do genetic variabilities play in the individual immune response to this viral infection. Here, we discuss the critical role T cells play in the orchestration of the antiviral response underlying the pathogenesis of the disease, COVID-19. We highlight the scientific rationale for comprehensive and longitudinal TCR analyses in COVID-19 and reason that analyzing TCR repertoire in COVID-19 patients would reveal important findings that may explain the outcome disparity observed in these patients. Finally, we provide a framework describing the different strategies, the advantages, and the challenges involved in obtaining useful TCR repertoire data to advance our fight against COVID-19.


Assuntos
Betacoronavirus/isolamento & purificação , Infecções por Coronavirus/epidemiologia , Pneumonia Viral/epidemiologia , Receptores de Antígenos de Linfócitos T/imunologia , Animais , Infecções por Coronavirus/genética , Infecções por Coronavirus/imunologia , Humanos , Pandemias , Pneumonia Viral/genética , Pneumonia Viral/imunologia , Linfócitos T/imunologia
14.
Proc Natl Acad Sci U S A ; 117(24): 13730-13739, 2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32482869

RESUMO

Merkel cell carcinoma (MCC) is a lethal skin cancer that metastasizes rapidly. Few effective treatments are available for patients with metastatic MCC. Poor intratumoral T cell infiltration and activation are major barriers that prevent MCC eradication by the immune system. However, the mechanisms that drive the immunologically restrictive tumor microenvironment remain poorly understood. In this study, we discovered that the innate immune regulator stimulator of IFN genes (STING) is completely silenced in MCCs. To reactivate STING in MCC, we developed an application of a human STING mutant, STINGS162A/G230I/Q266I, which we found to be readily stimulated by a mouse STING agonist, DMXAA. This STING molecule was efficiently delivered to MCC cells via an AAV vector. Introducing STINGS162A/G230I/Q266I expression and stimulating its activity by DMXAA in MCC cells reactivates their antitumor inflammatory cytokine/chemokine production. In response to MCC cells with restored STING, cocultured T cells expressing MCPyV-specific T cell receptors (TCRs) show increased cytokine production, migration toward tumor cells, and tumor cell killing. Our study therefore suggests that STING deficiency contributes to the immune suppressive nature of MCCs. More importantly, DMXAA stimulation of STINGS162A/G230I/Q266I causes robust cell death in MCCs as well as several other STING-silenced cancers. Because tumor antigens and DNA released by dying cancer cells have the potential to amplify innate immune response and activate antitumor adaptive responses, our finding indicates that targeted delivery and activation of STINGS162A/G230I/Q266I in tumor cells holds great therapeutic promise for the treatment of MCC and many other STING-deficient cancers.


Assuntos
Carcinoma de Célula de Merkel/imunologia , Proteínas de Membrana/imunologia , Neoplasias Cutâneas/imunologia , Carcinoma de Célula de Merkel/genética , Linhagem Celular Tumoral , Humanos , Imunidade Inata , Proteínas de Membrana/genética , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/imunologia , Transdução de Sinais/efeitos dos fármacos , Neoplasias Cutâneas/genética , Xantonas/farmacologia
15.
Proc Natl Acad Sci U S A ; 117(24): 13659-13669, 2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32482872

RESUMO

T cell maturation and activation depend upon T cell receptor (TCR) interactions with a wide variety of antigenic peptides displayed in a given major histocompatibility complex (MHC) context. Complementarity-determining region 3 (CDR3) is the most variable part of the TCRα and -ß chains, which govern interactions with peptide-MHC complexes. However, it remains unclear how the CDR3 landscape is shaped by individual MHC context during thymic selection of naïve T cells. We established two mouse strains carrying distinct allelic variants of H2-A and analyzed thymic and peripheral production and TCR repertoires of naïve conventional CD4+ T (Tconv) and naïve regulatory CD4+ T (Treg) cells. Compared with tuberculosis-resistant C57BL/6 (H2-Ab) mice, the tuberculosis-susceptible H2-Aj mice had fewer CD4+ T cells of both subsets in the thymus. In the periphery, this deficiency was only apparent for Tconv and was compensated for by peripheral reconstitution for Treg We show that H2-Aj favors selection of a narrower and more convergent repertoire with more hydrophobic and strongly interacting amino acid residues in the middle of CDR3α and CDR3ß, suggesting more stringent selection against a narrower peptide-MHC-II context. H2-Aj and H2-Ab mice have prominent reciprocal differences in CDR3α and CDR3ß features, probably reflecting distinct modes of TCR fitting to MHC-II variants. These data reveal the mechanics and extent of how MHC-II shapes the naïve CD4+ T cell CDR3 landscape, which essentially defines adaptive response to infections and self-antigens.


Assuntos
Regiões Determinantes de Complementaridade/imunologia , Antígenos de Histocompatibilidade Classe II/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Linfócitos T Reguladores/imunologia , Tuberculose/genética , Alelos , Animais , Linfócitos T CD4-Positivos/imunologia , Regiões Determinantes de Complementaridade/química , Regiões Determinantes de Complementaridade/genética , Antígenos de Histocompatibilidade Classe II/genética , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Receptores de Antígenos de Linfócitos T/química , Receptores de Antígenos de Linfócitos T/genética , Baço/imunologia , Linfócitos T Reguladores/química , Tuberculose/imunologia
16.
Trends Pharmacol Sci ; 41(8): 518-530, 2020 08.
Artigo em Inglês | MEDLINE | ID: covidwho-608511

RESUMO

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected several millions and killed more than quarter of a million worldwide to date. Important questions have remained unanswered: why some patients develop severe disease, while others do not; and what roles do genetic variabilities play in the individual immune response to this viral infection. Here, we discuss the critical role T cells play in the orchestration of the antiviral response underlying the pathogenesis of the disease, COVID-19. We highlight the scientific rationale for comprehensive and longitudinal TCR analyses in COVID-19 and reason that analyzing TCR repertoire in COVID-19 patients would reveal important findings that may explain the outcome disparity observed in these patients. Finally, we provide a framework describing the different strategies, the advantages, and the challenges involved in obtaining useful TCR repertoire data to advance our fight against COVID-19.


Assuntos
Betacoronavirus/isolamento & purificação , Infecções por Coronavirus/epidemiologia , Pneumonia Viral/epidemiologia , Receptores de Antígenos de Linfócitos T/imunologia , Animais , Infecções por Coronavirus/genética , Infecções por Coronavirus/imunologia , Humanos , Pandemias , Pneumonia Viral/genética , Pneumonia Viral/imunologia , Linfócitos T/imunologia
17.
Nat Commun ; 11(1): 2330, 2020 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-32393818

RESUMO

Recombinant T cell receptors (TCRs) can be used to redirect naïve T cells to eliminate virally infected or cancerous cells; however, they are plagued by low stability and uneven expression. Here, we use molecular modeling to identify mutations in the TCR constant domains (Cα/Cß) that increase the unfolding temperature of Cα/Cß by 20 °C, improve the expression of four separate α/ß TCRs by 3- to 10-fold, and improve the assembly and stability of TCRs with poor intrinsic stability. The stabilizing mutations rescue the expression of TCRs destabilized through variable domain mutation. The improved stability and folding of the TCRs reduces glycosylation, perhaps through conformational stabilization that restricts access to N-linked glycosylation enzymes. The Cα/Cß mutations enables antibody-like expression and assembly of well-behaved bispecific molecules that combine an anti-CD3 antibody with the stabilized TCR. These TCR/CD3 bispecifics can redirect T cells to kill tumor cells with target HLA/peptide on their surfaces in vitro.


Assuntos
Anticorpos Biespecíficos/imunologia , Biologia Computacional/métodos , Receptores de Antígenos de Linfócitos T/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Biespecíficos/química , Varredura Diferencial de Calorimetria , Citotoxicidade Imunológica , Imunoglobulina G/metabolismo , Camundongos , Mutação/genética , Polissacarídeos/metabolismo , Desnaturação Proteica , Estabilidade Proteica , Subunidades Proteicas/metabolismo , Receptores de Antígenos de Linfócitos T/química , Proteínas Recombinantes/metabolismo , Solubilidade , Temperatura
18.
PLoS Pathog ; 16(5): e1008244, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32365082

RESUMO

Viral escape from CD8+ cytotoxic T lymphocyte responses correlates with disease progression and represents a significant challenge for vaccination. Here, we demonstrate that CD8+ T cell recognition of the naturally occurring MHC-I-restricted LCMV-associated immune escape variant Y4F is restored following vaccination with a proline-altered peptide ligand (APL). The APL increases MHC/peptide (pMHC) complex stability, rigidifies the peptide and facilitates T cell receptor (TCR) recognition through reduced entropy costs. Structural analyses of pMHC complexes before and after TCR binding, combined with biophysical analyses, revealed that although the TCR binds similarly to all complexes, the p3P modification alters the conformations of a very limited amount of specific MHC and peptide residues, facilitating efficient TCR recognition. This approach can be easily introduced in peptides restricted to other MHC alleles, and can be combined with currently available and future vaccination protocols in order to prevent viral immune escape.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Vírus da Coriomeningite Linfocítica/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Animais , Antivirais/metabolismo , Linfócitos T CD8-Positivos/fisiologia , Proteínas de Ligação a DNA/imunologia , Epitopos/imunologia , Epitopos de Linfócito T/imunologia , Genes RAG-1/imunologia , Ligantes , Ativação Linfocitária/imunologia , Vírus da Coriomeningite Linfocítica/genética , Vírus da Coriomeningite Linfocítica/patogenicidade , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Peptídeos/metabolismo , Prolina/metabolismo , Ligação Proteica , Linfócitos T Citotóxicos/imunologia , Vacinação/métodos
19.
Proc Natl Acad Sci U S A ; 117(23): 12826-12835, 2020 06 09.
Artigo em Inglês | MEDLINE | ID: mdl-32461371

RESUMO

Complete cancer regression occurs in a subset of patients following adoptive T cell therapy (ACT) of ex vivo expanded tumor-infiltrating lymphocytes (TILs). However, the low success rate presents a great challenge to broader clinical application. To provide insight into TIL-based immunotherapy, we studied a successful case of ACT where regression was observed against tumors carrying the hotspot mutation G12D in the KRAS oncogene. Four T cell receptors (TCRs) made up the TIL infusion and recognized two KRAS-G12D neoantigens, a nonamer and a decamer, all restricted by human leukocyte antigen (HLA) C*08:02. Three of them (TCR9a, 9b, and 9c) were nonamer-specific, while one was decamer-specific (TCR10). We show that only mutant G12D but not the wild-type peptides stabilized HLA-C*08:02 due to the formation of a critical anchor salt bridge to HLA-C. Therapeutic TCRs exhibited high affinities, ranging from nanomolar to low micromolar. Intriguingly, TCR binding affinities to HLA-C inversely correlated with their persistence in vivo, suggesting the importance of antigenic affinity in the function of therapeutic T cells. Crystal structures of TCR-HLA-C complexes revealed that TCR9a to 9c recognized G12D nonamer with multiple conserved contacts through shared CDR2ß and CDR3α. This allowed CDR3ß variation to confer different affinities via a variable HLA-C contact, generating an oligoclonal response. TCR10 recognized an induced and distinct G12D decamer conformation. Thus, this successful case of ACT included oligoclonal TCRs of high affinity recognizing distinct conformations of neoantigens. Our study revealed the potential of a structural approach to inform clinical efforts in targeting KRAS-G12D tumors by immunotherapy and has general implications for T cell-based immunotherapies.


Assuntos
Antígenos de Neoplasias/imunologia , Imunoterapia Adotiva/métodos , Proteínas Proto-Oncogênicas p21(ras)/genética , Receptores de Antígenos de Linfócitos T/imunologia , Linfócitos T/imunologia , Apresentação do Antígeno , Antígenos de Neoplasias/química , Sítios de Ligação , Antígenos HLA-C/química , Antígenos HLA-C/imunologia , Humanos , Células Jurkat , Mutação de Sentido Incorreto , Proteínas do Tecido Nervoso/química , Proteínas do Tecido Nervoso/imunologia , Ligação Proteica , Proteínas Proto-Oncogênicas p21(ras)/química , Proteínas Proto-Oncogênicas p21(ras)/imunologia , Receptores de Antígenos de Linfócitos T/química
20.
Pol Arch Intern Med ; 130(7-8): 662-667, 2020 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-32449333

RESUMO

The intriguing aspects of severe acute respiratory syndrome coronavirus 2 (SARS­CoV­2) are the high rate of spread and rapid progression of pneumonitis. Confronted with thousands of deaths daily worldwide, we have to quickly build the rationale behind the treatment, taking advantage of past analogues. When a new virus strikes, T­cell receptor γδ cells are in the first line of defense, activated by stress molecules and recognizing some epitopes in a process that is major histocompatibility complex-independent but still specific, eg, cytomegalovirus, as well as participating in the regulatory mechanism-both characteristics are useful in fighting SARS­CoV­2. Most deaths occur due to pneumonitis, in the course of which overwhelming inflammation impairs blood oxygenation, calling for artificial ventilation. In fatal cases of coronavirus disease 2019, the balance between the immune response and the inflammatory outcome fails and, therefore, patients at risk, mostly the elderly, show higher levels of anti-SARS­CoV­2 antibodies and enhanced inflammation in the lungs. Apparently, there is no feedback control over the antibody production. The investigational use of convalescent plasma, providing antibodies taken from patients who have recovered, was shown to be effective, likely through exerting idiotype­associated negative control of antibody production. Similarly, the use of mesenchymal stem cells may assist the body regulatory mechanisms, considering the anti­inflammatory potential of these cells. The use of these 2 immunotherapeutic tools is understandable based on basic immunology and this knowledge may direct the efforts of the medical community aimed at combating the virus.


Assuntos
Betacoronavirus/imunologia , Infecções por Coronavirus/imunologia , Pneumonia Viral/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Citometria de Fluxo , Humanos , Sistema Imunitário , Pandemias
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