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1.
Immunogenetics ; 71(8-9): 575-587, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31520134

RESUMO

The major histocompatibility complex (MHC) is one of the most diverse genetic regions under pathogen-driven selection because of its central role in antigen binding and immunity. The highest MHC variability, both in terms of the number of individual alleles and gene copies, has so far been found in passerine birds; this is probably attributable to passerine adaptation to both a wide geographic range and a diverse array of habitats. If extraordinary high MHC variation and duplication rates are adaptive features under selection during the evolution of ecologically and taxonomically diverse species, then similarly diverse MHC architectures should be found in bats. Bats are an extremely species-rich mammalian group that is globally widely distributed. Many bat species roost in multitudinous groups and have high contact rates with pathogens, conspecifics, and allospecifics. We have characterized the MHC class I diversity in 116 Panamanian Seba's short-tailed bats (Carollia perspicillata), a widely distributed, generalist, neotropical species. We have detected a remarkable individual and population-level diversity of MHC class I genes, with between seven and 22 alleles and a unique genotype in each individual. This diversity is comparable with that reported in passerine birds and, in both taxonomic groups, further variability has evolved through length polymorphisms. Our findings support the hypothesis that, for species with a geographically broader range, high MHC class I variability is particularly adaptive. Investigation of the details of the underlying adaptive processes and the role of the high MHC diversity in pathogen resistance are important next steps for a better understanding of the role of bats in viral evolution and as carriers of several deadly zoonotic viruses.


Assuntos
Quirópteros/genética , Evolução Molecular , Antígenos de Histocompatibilidade Classe I/genética , Polimorfismo Genético , Seleção Genética , Sequência de Aminoácidos , Animais , Quirópteros/imunologia , Éxons , Frequência do Gene , Geografia , Antígenos de Histocompatibilidade Classe I/imunologia , Filogenia , Homologia de Sequência
2.
Nat Immunol ; 20(9): 1110-1128, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31406380

RESUMO

In recent years, a population of unconventional T cells called 'mucosal-associated invariant T cells' (MAIT cells) has captured the attention of immunologists and clinicians due to their abundance in humans, their involvement in a broad range of infectious and non-infectious diseases and their unusual specificity for microbial riboflavin-derivative antigens presented by the major histocompatibility complex (MHC) class I-like protein MR1. MAIT cells use a limited T cell antigen receptor (TCR) repertoire with public antigen specificities that are conserved across species. They can be activated by TCR-dependent and TCR-independent mechanisms and exhibit rapid, innate-like effector responses. Here we review evidence showing that MAIT cells are a key component of the immune system and discuss their basic biology, development, role in disease and immunotherapeutic potential.


Assuntos
Apresentação do Antígeno/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Antígenos de Histocompatibilidade Menor/imunologia , Células T Invariáveis Associadas à Mucosa/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Animais , Antígenos/imunologia , Suscetibilidade a Doenças/imunologia , Humanos , Ativação Linfocitária/imunologia , Camundongos , Neoplasias/imunologia
3.
Cancer Immunol Immunother ; 68(10): 1689-1700, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31375885

RESUMO

Immunotherapy aims to activate the immune system to fight cancer in a very specific and targeted manner. Despite the success of different immunotherapeutic strategies, in particular antibodies directed against checkpoints as well as adoptive T-cell therapy, the response of patients is limited in different types of cancers. This attributes to escape of the tumor from immune surveillance and development of acquired resistances during therapy. In this review, the different evasion and resistance mechanisms that limit the efficacy of immunotherapies targeting tumor-associated antigens presented by major histocompatibility complex molecules on the surface of the malignant cells are summarized. Overcoming these escape mechanisms is a great challenge, but might lead to a better clinical outcome of patients and is therefore currently a major focus of research.


Assuntos
Imunoterapia/métodos , Neoplasias/terapia , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Evasão Tumoral , Apresentação do Antígeno , Antígenos HLA-G/fisiologia , Antígenos de Histocompatibilidade Classe I/imunologia , Humanos
4.
Cancer Immunol Immunother ; 68(9): 1429-1441, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31428800

RESUMO

MHC class I-related chain A (MICA) is one of the major ligands for natural killer group 2 member D (NKG2D), which is an activating NK receptor. MICA is expressed on the surface of human epithelial tumor cells, and its shedding from tumor cells leads to immunosuppression. To activate immune response in the tumor microenvironment, we designed an anti-VEGFR2-MICA bispecific antibody (JZC01), consisting of MICA and an anti-VEGFR2 single chain antibody fragment (JZC00) and explored its potential anti-tumor activity. JZC01 targeted vascular endothelial growth factor receptor 2 (VEGFR2) and inhibited tumorigenesis by blocking the VEGFR2 signaling pathway. Additionally, JZC01 promoted NK and CD8+ T cells to release IFN-γ and engaged activated lymphocytes to lysis of VEGFR2-expressing tumor cells. The in vivo anti-tumor activity of JZC01 was investigated by establishing a Lewis lung cancer cell-transplanted mouse model. It effectively reduced the tumor vascular density and increased the infiltration and activation of NK and CD8+ T cells in the tumor microenvironment. Thus, JZC01 functions in anti-tumor angiogenesis and anti-tumor immune activation, and showed improved anti-tumor efficacy combined with docetaxel, which provides a new insight into anti-tumor therapy.


Assuntos
Anticorpos Biespecíficos/uso terapêutico , Linfócitos T CD8-Positivos/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Imunoterapia/métodos , Células Matadoras Naturais/imunologia , Neoplasias Pulmonares/terapia , Linfócitos do Interstício Tumoral/imunologia , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/imunologia , Animais , Anticorpos Biespecíficos/genética , Apoptose , Carcinoma Pulmonar de Lewis , Citotoxicidade Imunológica , Modelos Animais de Doenças , Humanos , Tolerância Imunológica , Interferon gama/metabolismo , Neoplasias Pulmonares/imunologia , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos C57BL , Transdução de Sinais/efeitos dos fármacos , Microambiente Tumoral
5.
Nat Commun ; 10(1): 3020, 2019 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-31289263

RESUMO

Human cytomegalovirus (HCMV) can persistently infect humans, but how HCMV avoids humoral immunity is not clear. The neonatal Fc receptor (FcRn) controls IgG transport from the mother to the fetus and prolongs IgG half-life. Here we show that US11 inhibits the assembly of FcRn with ß2m and retains FcRn in the endoplasmic reticulum (ER), consequently blocking FcRn trafficking to the endosome. Furthermore, US11 recruits the ubiquitin enzymes Derlin-1, TMEM129 and UbE2J2 to engage FcRn, consequently initiating the dislocation of FcRn from the ER to the cytosol and facilitating its degradation. Importantly, US11 inhibits IgG-FcRn binding, resulting in a reduction of IgG transcytosis across intestinal or placental epithelial cells and IgG degradation in endothelial cells. Hence, these results identify the mechanism by which HCMV infection exploits an ER-associated degradation pathway through US11 to disable FcRn functions. These results have implications for vaccine development and immune surveillance.


Assuntos
Infecções por Citomegalovirus/imunologia , Citomegalovirus/imunologia , Antígenos de Histocompatibilidade Classe I/metabolismo , Evasão da Resposta Imune , Imunidade Humoral , Proteínas de Ligação a RNA/metabolismo , Receptores Fc/metabolismo , Proteínas Virais/metabolismo , Linhagem Celular , Citomegalovirus/patogenicidade , Infecções por Citomegalovirus/virologia , Degradação Associada com o Retículo Endoplasmático/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Humanos , Imunoglobulina G/imunologia , Imunoglobulina G/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Mutagênese Sítio-Dirigida , RNA Interferente Pequeno/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/imunologia , Receptores Fc/imunologia , Enzimas de Conjugação de Ubiquitina/genética , Enzimas de Conjugação de Ubiquitina/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , Proteínas Virais/genética , Proteínas Virais/imunologia
6.
Scand J Immunol ; 90(5): e12804, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31267559

RESUMO

Immune checkpoint inhibitors are among the newest, cutting-edge methods for the treatment of cancer. Currently, they primarily influence T cell adaptive immunotherapy targeting the PD-1/PD-L1 and CTLA-4/B7 signalling pathways. These inhibitors fight cancer by reactivating the patient's own adaptive immune system, with good results in many cancers. With the discovery of the "Don't Eat Me" molecule, CD47, antibody-based drugs that target the macrophage-related innate immunosuppressive signalling pathway, CD47-SIRPα, have been developed and have achieved stunning results in the laboratory and the clinic, but there remain unexplained instances of tumour immune escape. While investigating the immunological tolerance of cancer to anti-CD47 antibodies, a second "Don't Eat Me" molecule on tumour cells, beta 2 microglobulin (ß2m), a component of MHC class I, was described. Some tumour cells reduce their surface expression of MHC class I to escape T cell recognition. However, other tumour cells highly express ß2m complexed with the MHC class I heavy chain to send a "Don't Eat Me" signal by binding to leucocyte immunoglobulin-like receptor family B, member 1 (LILRB1) on macrophages, leading to a loss of immune surveillance. Investigating the mechanisms underlying this immunosuppressive MHC class I-LILRB1 signalling axis in tumour-associated macrophages will be useful in developing therapies to restore macrophage function and control MHC class I signalling in patient tumours. The goal is to promote adaptive immunity while suppressing the innate immune response to tumours. This work will identify new therapeutic targets for the development of pharmaceutical-based tumour immunotherapy.


Assuntos
Antígenos CD/imunologia , Tolerância Imunológica/imunologia , Receptor B1 de Leucócitos Semelhante a Imunoglobulina/imunologia , Neoplasias/terapia , Evasão Tumoral/imunologia , Microglobulina beta-2/imunologia , Imunidade Adaptativa/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Humanos , Imunidade Inata/imunologia , Macrófagos/imunologia , Transdução de Sinais/imunologia , Linfócitos T/imunologia
7.
Comp Immunol Microbiol Infect Dis ; 65: 238-245, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31300121

RESUMO

Japanese encephalitis virus (JEV) and West Nile virus (WNV) are two major mosquito borne flaviviruses belonging to same serocomplex. JEV is transmitted by Culex mosquitoes and the reservoir host for the virus is pigs and/or water birds. WNV is also transmitted by Culex mosquitoes and reservoir host in this case is birds. It can also be transmitted through contact with other infected animals, their blood, or other tissues. The envelope protein of these viruses is the major source of epitopes and provides protective immunity. Bioinformatics tools were used to identify conserved epitopes in the envelope protein of these viruses. A conserved peptide "TPVGRLVTVNPFV" present in both the viruses containing predicted T and B cell epitopes was found. The model of one of the predicted epitope was generated and upon docking it bound in the groove of HLA-A0201 Class I MHC molecule. Further, it was amenable to proteasomal cleavage enhancing its chances of processing by cytosolic pathway. The peptide was found to be non toxic, non allergenic and stable in mammalian cells based on database search. The population coverage was pan world and nearly 70% identity of the peptide was found in the Zika virus envelope protein. The peptide was located in the domain III of envelope protein which is the exposed domain therefore B cell receptors may recognize this peptide easily. The conserved peptide containing T and B cell epitopes can have future application for designing epitope based vaccines for both JEV and WNV.


Assuntos
Vírus da Encefalite Japonesa (Espécie) , Mapeamento de Epitopos , Epitopos de Linfócito B/imunologia , Epitopos de Linfócito T/imunologia , Proteínas do Envelope Viral/imunologia , Vírus do Nilo Ocidental , Biologia Computacional , Antígenos de Histocompatibilidade Classe I/imunologia , Antígenos de Histocompatibilidade Classe II/imunologia , Simulação de Acoplamento Molecular , Peptídeos/imunologia , Ligação Proteica , Proteínas do Envelope Viral/genética , Vacinas Virais/imunologia
8.
Immunogenetics ; 71(7): 479-487, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31270568

RESUMO

Xenotransplantation of pig organs into people may help alleviate the critical shortage of donors which faces organ transplantation. Unfortunately, human antibodies vigorously attack pig tissues preventing the clinical application of xenotransplantation. The swine leukocyte antigens (SLA), homologs of human HLA molecules, can be xenoantigens. SLA molecules, encoded by genes in the pig major histocompatibility complex, contribute to protective immune responses in pig. Therefore, simply inactivating them through genome engineering could reduce the ability of the human immune system to surveil transplanted pig organs for infectious disease or the development of neoplasms. A potential solution to this problem is to identify and modify epitopes in SLA proteins to eliminate their contribution to humoral xenoantigenicity while retaining their biosynthetic competence and ability to contribute to protective immunity. We previously showed that class II SLA proteins were recognized as xenoantigens and mutating arginine at position 55 to proline, in an SLA-DQ beta chain, could reduce human antibody binding. Here, we extend these observations by creating several additional point mutants at position 55. Using a panel of monoclonal antibodies specific for class II SLA proteins, we show that these mutants remain biosynthetically competent. Examining antibody binding to these variants shows that point mutagenesis can reduce, eliminate, or increase antibody binding to class II SLA proteins. Individual mutations can have opposite effects on antibody binding when comparing samples from different people. We also performed a preliminary analysis of creating point mutants near to position 55 to demonstrate that manipulating additional residues also affects antibody reactivity.


Assuntos
Anticorpos Monoclonais/metabolismo , Epitopos/genética , Antígenos de Histocompatibilidade Classe I/metabolismo , Animais , Antígenos Heterófilos/genética , Arginina/genética , Células HEK293 , Antígenos de Histocompatibilidade Classe I/genética , Antígenos de Histocompatibilidade Classe I/imunologia , Humanos , Mutagênese Sítio-Dirigida , Mutação Puntual , Suínos
9.
Pol J Microbiol ; 68(2): 233-246, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31250594

RESUMO

The aim of this study was to identify the potential vaccine antigens in Corynebacterium diphtheriae strains by in silico analysis of the amino acid variation in the 67-72p surface protein that is involved in the colonization and induction of epithelial cell apoptosis in the early stages of infection. The analysis of pili structural proteins involved in bacterial adherence to host cells and related to various types of infections was also performed. A polymerase chain reaction (PCR) was carried out to amplify the genes encoding the 67-72p protein and three pili structural proteins (SpaC, SpaI, SapD) and the products obtained were sequenced. The nucleotide sequences of the particular genes were translated into amino acid sequences, which were then matched among all the tested strains using bioinformatics tools. In the last step, the affinity of the tested proteins to major histocompatibility complex (MHC) classes I and II, and linear B-cell epitopes was analyzed. The variations in the nucleotide sequence of the 67-72p protein and pili structural proteins among C. diphtheriae strains isolated from various infections were noted. A transposition of the insertion sequence within the gene encoding the SpaC pili structural proteins was also detected. In addition, the bioinformatics analyses enabled the identification of epitopes for B-cells and T-cells in the conserved regions of the proteins, thus, demonstrating that these proteins could be used as antigens in the potential vaccine development. The results identified the most conserved regions in all tested proteins that are exposed on the surface of C. diphtheriae cells.The aim of this study was to identify the potential vaccine antigens in Corynebacterium diphtheriae strains by in silico analysis of the amino acid variation in the 67­72p surface protein that is involved in the colonization and induction of epithelial cell apoptosis in the early stages of infection. The analysis of pili structural proteins involved in bacterial adherence to host cells and related to various types of infections was also performed. A polymerase chain reaction (PCR) was carried out to amplify the genes encoding the 67­72p protein and three pili structural proteins (SpaC, SpaI, SapD) and the products obtained were sequenced. The nucleotide sequences of the particular genes were translated into amino acid sequences, which were then matched among all the tested strains using bioinformatics tools. In the last step, the affinity of the tested proteins to major histocompatibility complex (MHC) classes I and II, and linear B-cell epitopes was analyzed. The variations in the nucleotide sequence of the 67­72p protein and pili structural proteins among C. diphtheriae strains isolated from various infections were noted. A transposition of the insertion sequence within the gene encoding the SpaC pili structural proteins was also detected. In addition, the bioinformatics analyses enabled the identification of epitopes for B-cells and T-cells in the conserved regions of the proteins, thus, demonstrating that these proteins could be used as antigens in the potential vaccine development. The results identified the most conserved regions in all tested proteins that are exposed on the surface of C. diphtheriae cells.


Assuntos
Adesinas Bacterianas/genética , Antígenos de Bactérias/genética , Corynebacterium diphtheriae/genética , Toxoide Diftérico/genética , Difteria/prevenção & controle , Variação Genética , Proteínas de Membrana/genética , Adesinas Bacterianas/imunologia , Antígenos de Bactérias/imunologia , Biologia Computacional , Sequência Conservada , Corynebacterium diphtheriae/imunologia , Toxoide Diftérico/imunologia , Epitopos de Linfócito B/genética , Epitopos de Linfócito B/imunologia , Epitopos de Linfócito T/genética , Epitopos de Linfócito T/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Antígenos de Histocompatibilidade Classe II/imunologia , Proteínas de Membrana/imunologia , Reação em Cadeia da Polimerase , Ligação Proteica , Análise de Sequência de DNA
10.
Mol Immunol ; 112: 274-282, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31226552

RESUMO

The viral peptides presentation by major histocompatibility complex class I (MHC I) molecules play a pivotal role in T-cell recognition and the subsequent virus clearance. This process is delicately adjusted by the variant residues of MHC I, especially the residues in the peptide binding groove (PBG). In a series of MHC I molecules, a salt bridge is formed above the N-terminus of the peptides. However, the potential impact of the salt bridge on peptide binding and T-cell receptor (TCR) recognition of MHC I, as well as the corresponding molecular basis, are still largely unknown. Herein, we determined the structures of HLA-B*4001 and H-2Kd in which two different types of salt bridges (Arg62-Glu163 or Arg66-Glu163) across the PBG were observed. Although the two salt bridges led to different conformation shifts of both the MHC I α helix and the peptides, binding of the peptides with the salt bridge residues was relatively conserved. Furthermore, through a series of in vitro and in vivo investigations, we found that MHC I mutations that disrupt the salt bridge alleviate peptide binding and can weaken the TCR recognition of MHC I-peptide complexes. Our study may provide key references for understanding MHC I-restricted peptide recognition by T-cells.


Assuntos
Apresentação do Antígeno/imunologia , Genes MHC Classe I/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Peptídeos/imunologia , Ligação Proteica/imunologia , Linfócitos T/imunologia , Animais , Sítios de Ligação/imunologia , Feminino , Antígenos HLA-B/imunologia , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Conformação Proteica , Receptores de Antígenos de Linfócitos T/imunologia
11.
Nat Commun ; 10(1): 2387, 2019 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-31160572

RESUMO

Senescent cells accumulate in human tissues during ageing and contribute to age-related pathologies. The mechanisms responsible for their accumulation are unclear. Here we show that senescent dermal fibroblasts express the non-classical MHC molecule HLA-E, which interacts with the inhibitory receptor NKG2A expressed by NK and highly differentiated CD8+ T cells to inhibit immune responses against senescent cells. HLA-E expression is induced by senescence-associated secretary phenotype-related pro-inflammatory cytokines, and is regulated by p38 MAP kinase signalling in vitro. Consistently, HLA-E expression is increased on senescent cells in human skin sections from old individuals, when compared with those from young, and in human melanocytic nevi relative to normal skin. Lastly, blocking the interaction between HLA-E and NKG2A boosts immune responses against senescent cells in vitro. We thus propose that increased HLA-E expression contributes to persistence of senescent cells in tissues, thereby suggesting a new strategy for eliminating senescent cells during ageing.


Assuntos
Envelhecimento/imunologia , Linfócitos T CD8-Positivos/imunologia , Senescência Celular/imunologia , Fibroblastos/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Células Matadoras Naturais/imunologia , Subfamília C de Receptores Semelhantes a Lectina de Células NK/imunologia , Adulto , Idoso , Envelhecimento/patologia , Citocinas/imunologia , Derme/citologia , Fibroblastos/patologia , Humanos , Técnicas In Vitro , Nevo Pigmentado/congênito , Nevo Pigmentado/imunologia , Nevo Pigmentado/patologia , Fenótipo , RNA Interferente Pequeno , Transdução de Sinais , Pele/imunologia , Pele/patologia , Adulto Jovem , Proteínas Quinases p38 Ativadas por Mitógeno/imunologia
12.
Eur J Histochem ; 63(2)2019 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-31113192

RESUMO

Biomarkers may hold the key towards development and improvement of personalized cancer treatment. For instance, tumour expression of immune system-related proteins may reveal the tumour immune status and, accordingly, determine choice for type of immunotherapy. Therefore, objective evaluation of tumour biomarker expression is needed but often challenging. For instance, human leukocyte antigen (HLA) class I tumour epithelium expression is cumbersome to quantify by eye due to its presence on both tumour epithelial cells and tumour stromal cells, as well as tumour-infiltrating immune cells. In this study, we solved this problem by setting up an immunohistochemical (IHC) double staining using a tissue microarray (TMA) of rectal tumours wherein HLA class I expression was coloured with a blue chromogen, whereas non-epithelial tissue was visualized with a brown chromogen. We subsequently developed a semi-automated image analysis method that identified tumour epithelium as well as the percentage of HLA class I-positive tumour epithelium. Using this technique, we compared HCA2/HC10 and EMR8-5 antibodies for the assessment of HLA class I tumour expression and concluded that EMR8-5 is the superior antibody for this purpose. This IHC double staining can in principle be used for scoring of any biomarker expressed by tumour epithelium.


Assuntos
Antígenos de Histocompatibilidade Classe I/metabolismo , Neoplasias Retais/metabolismo , Animais , Anticorpos Monoclonais Murinos/imunologia , Biomarcadores Tumorais/imunologia , Biomarcadores Tumorais/metabolismo , Epitélio/metabolismo , Antígenos de Histocompatibilidade Classe I/imunologia , Humanos , Imuno-Histoquímica/métodos , Camundongos , Coelhos , Neoplasias Retais/patologia , Análise Serial de Tecidos
13.
Nat Commun ; 10(1): 2243, 2019 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-31113973

RESUMO

Mucosal-associated invariant T (MAIT) cells express an invariant TRAV1/TRAJ33 TCR-α chain and are restricted to the MHC-I-like molecule, MR1. Whether MAIT cell development depends on this invariant TCR-α chain is unclear. Here we generate Traj33-deficient mice and show that they are highly depleted of MAIT cells; however, a residual population remains and can respond to exogenous antigen in vitro or pulmonary Legionella challenge in vivo. These residual cells include some that express Trav1+ TCRs with conservative Traj-gene substitutions, and others that express Trav1- TCRs with a broad range of Traj genes. We further report that human TRAV1-2- MR1-restricted T cells contain both MAIT-like and non-MAIT-like cells, as judged by their TCR repertoire, antigen reactivity and phenotypic features. These include a MAIT-like population that expresses a public, canonical TRAV36+ TRBV28+ TCR. Our findings highlight the TCR diversity and the resulting potential impact on antigen recognition by MR1-restricted T cells.


Assuntos
Antígenos de Histocompatibilidade Classe I/metabolismo , Legionelose/imunologia , Antígenos de Histocompatibilidade Menor/metabolismo , Células T Invariáveis Associadas à Mucosa/imunologia , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Animais , Apresentação do Antígeno/imunologia , Modelos Animais de Doenças , Células HEK293 , Antígenos de Histocompatibilidade Classe I/imunologia , Humanos , Legionella/imunologia , Legionelose/microbiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Antígenos de Histocompatibilidade Menor/imunologia , Células T Invariáveis Associadas à Mucosa/metabolismo , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Receptores de Antígenos de Linfócitos T alfa-beta/imunologia
14.
J Exp Clin Cancer Res ; 38(1): 192, 2019 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-31088566

RESUMO

BACKGROUND: Modulation of cell surface expression of MHC class I chain-related protein A/B (MICA/B) has been proven to be one of the mechanisms by which tumor cells escape from NK cell-mediated killing. Abnormal metabolic condition, such as high glucose, may create a cellular stress milieu to induce immune dysfunction. Hyperglycemia is frequently presented in the majority of pancreatic cancer patients and is associated with poor prognosis. In this study, we aimed to detect the effects of high glucose on NK cell-mediated killing on pancreatic cancer cells through reduction of MICA/B expression. METHODS: The lysis of NK cells on pancreatic cancer cells were compared at different glucose concentrations through lactate dehydrogenase release assay. Then, qPCR, Western Blot, Flow cytometry and Immunofluorescence were used to identify the effect of high glucose on expression of MICA/B, Bmi1, GATA2, phosphorylated AMPK to explore the underlying mechanisms in the process. Moreover, an animal model with diabetes mellitus was established to explore the role of high glucose on NK cell-mediated cytotoxicity on pancreatic cancer in vivo. RESULTS: In our study, high glucose protects pancreatic cancer from NK cell-mediated killing through suppressing MICA/B expression. Bmi1, a polycomb group (PcG) protein, was found to be up-regulated by high glucose, and mediated the inhibition of MICA/B expression through promoting GATA2 in pancreatic cancer. Moreover, high glucose inhibited AMP-activated protein kinase signaling, leading to high expression of Bmi1. CONCLUSION: Our findings identify that high glucose may promote the immune escape of pancreatic cancer cells under hyperglycemic tumor microenvironment. In this process, constitutive activation of AMPK-Bmi1-GATA2 axis could mediate MICA/B inhibition, which may serve as a therapeutic target for further intervention of pancreatic cancer immune evasion.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Fator de Transcrição GATA2/metabolismo , Glucose/metabolismo , Antígenos de Histocompatibilidade Classe I/imunologia , Neoplasias Pancreáticas/imunologia , Neoplasias Pancreáticas/metabolismo , Complexo Repressor Polycomb 1/metabolismo , Evasão Tumoral/imunologia , Animais , Glicemia , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Citotoxicidade Imunológica , Expressão Gênica , Antígenos de Histocompatibilidade Classe I/genética , Antígenos de Histocompatibilidade Classe I/metabolismo , Humanos , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Masculino , Camundongos , Neoplasias Pancreáticas/sangue , Neoplasias Pancreáticas/genética , Transdução de Sinais , Microambiente Tumoral
15.
Science ; 364(6439): 480-484, 2019 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-31048489

RESUMO

Mutationally constrained epitopes of variable pathogens represent promising targets for vaccine design but are not reliably identified by sequence conservation. In this study, we employed structure-based network analysis, which applies network theory to HIV protein structure data to quantitate the topological importance of individual amino acid residues. Mutation of residues at important network positions disproportionately impaired viral replication and occurred with high frequency in epitopes presented by protective human leukocyte antigen (HLA) class I alleles. Moreover, CD8+ T cell targeting of highly networked epitopes distinguished individuals who naturally control HIV, even in the absence of protective HLA alleles. This approach thereby provides a mechanistic basis for immune control and a means to identify CD8+ T cell epitopes of topological importance for rational immunogen design, including a T cell-based HIV vaccine.


Assuntos
Vacinas contra a AIDS/genética , Vacinas contra a AIDS/imunologia , Síndrome de Imunodeficiência Adquirida/prevenção & controle , Linfócitos T CD8-Positivos/imunologia , Epitopos de Linfócito T/genética , Epitopos de Linfócito T/imunologia , HIV-1/imunologia , Alelos , Sequência Conservada , Antígenos HLA-B/genética , Antígenos HLA-B/imunologia , Antígenos de Histocompatibilidade Classe I/genética , Antígenos de Histocompatibilidade Classe I/imunologia , Humanos , Mutação , Proteoma/genética , Proteoma/imunologia , Replicação Viral , Produtos do Gene gag do Vírus da Imunodeficiência Humana
16.
Mol Biol (Mosk) ; 53(2): 303-310, 2019.
Artigo em Russo | MEDLINE | ID: mdl-31099780

RESUMO

Soluble human leukocyte antigen G (sHLA-G) plays a key role in pregnancy through interaction with decidual natural killer (dNK) cell inhibitory receptors at the maternal-fetal interface. To demonstrate the possible role of sHLA-G during the pregnancy with Toxoplasma gondii infection, we compared the concentration of a murine functional homolog of sHLA-G, Qa-2, in T. gondii infected and non-infected pregnant C57BL/6 mice, and that of sHLA-G in BeWo culture supernatant. In addition, the levels of KIR2DL4 expressed on human dNK cells and NKG2A in pregnant mice were evaluated. We showed that T. gondii infection result in significant increase in the level of Qa-2 and NKG2A in pregnant mice. sHLA-G and KIR2DL4 in human samples were also significantly upregulated under the condition of T. gondii infection. The further treatment with sHLA-G antibody could reduce the expression level of KIR2DL4 which was upregulated by T. gondii infection. In summary, sHLA-G could upregulate the expression level of KIR2DL4 which lead to excessive immunological tolerance, and further contributed to T. gondii immunity escaping and affecting fetus via vertical transmission which may lead to adverse outcomes.


Assuntos
Antígenos HLA-G/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Transmissão Vertical de Doença Infecciosa , Toxoplasmose/imunologia , Toxoplasmose/transmissão , Animais , Decídua/imunologia , Feminino , Antígenos HLA-G/química , Antígenos de Histocompatibilidade Classe I/química , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Gravidez , Solubilidade , Toxoplasma
17.
Nat Protoc ; 14(6): 1687-1707, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31092913

RESUMO

Peptide antigens bound to molecules encoded by the major histocompatibility complex (MHC) and presented on the cell surface form the targets of T lymphocytes. This critical arm of the adaptive immune system facilitates the eradication of pathogen-infected and cancerous cells, as well as the production of antibodies. Methods to identify these peptide antigens are critical to the development of new vaccines, for which the goal is the generation of effective adaptive immune responses and long-lasting immune memory. Here, we describe a robust protocol for the identification of MHC-bound peptides from cell lines and tissues, using nano-ultra-performance liquid chromatography coupled to high-resolution mass spectrometry (nUPLC-MS/MS) and recent improvements in methods for isolation and characterization of these peptides. The protocol starts with the immunoaffinity capture of naturally processed MHC-peptide complexes. The peptides dissociate from the class I human leukocyte antigens (HLAs) upon acid denaturation. This peptide cargo is then extracted and separated into fractions by HPLC, and the peptides in these fractions are identified using nUPLC-MS/MS. With this protocol, several thousand peptides can be identified from a wide variety of cell types, including cancerous and infected cells and those from tissues, with a turnaround time of 2-3 d.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Antígenos de Histocompatibilidade/imunologia , Peptídeos/análise , Peptídeos/imunologia , Espectrometria de Massas em Tandem/métodos , Sequência de Aminoácidos , Animais , Linhagem Celular , Células Cultivadas , Precipitação Química , Cromatografia de Afinidade/métodos , Antígenos de Histocompatibilidade Classe I/imunologia , Humanos , Complexo Principal de Histocompatibilidade , Camundongos
18.
Cancer Immunol Immunother ; 68(6): 983-990, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30993371

RESUMO

BACKGROUND: Merkel cell carcinoma (MCC) is an aggressive skin cancer in which PD-1/PD-L1 blockade has shown remarkable response rates. However, a significant proportion of patients shows primary or secondary resistance against PD-1/PD-L1 inhibition, with HLA class-I downregulation and insufficient influx of CD8+ T cells into the tumor as possible immune escape mechanisms. Histone deacetylase inhibitors (HDACi) have been demonstrated to reverse low HLA class-I expression caused by epigenetic downregulation of the antigen machinery (APM) in vitro and in pre-clinical models in vivo. CASE PRESENTATIONS: We report four cases of patients with metastatic MCC who did not respond to immunotherapy by PD-1/PD-L1 blockade. Two of the patients received, subsequently, the HDACi panobinostat in combination with PD-1/PD-L1 blockade. Tumor biopsies of the patients were analyzed for cellular and molecular markers of antigen processing and presentation as well as the degree of T-cell infiltration. RESULTS AND CONCLUSION: Low expression of APM-related genes associated with low HLA class-I surface expression was observed in all MCC patients, progressing on PD-1/PD-L1 blockade. In one evaluable patient, of the two treated with the combination therapy of the HDACi, panobinostat and PD-1/PD-L1 blockade, reintroduction of HLA class-I-related genes, enhanced HLA class-I surface expression, and elevated CD8+ T-cell infiltration into the MCC tumor tissue were observed; however, these changes did not translate into a clinical benefit. Our findings suggest that HDACi may be useful to overcome HLA class-I downregulation as a resistance mechanism against anti-PD-1/PD-L1 antibodies in MCC patients. Prospective clinical trials are needed to evaluate this notion.


Assuntos
Anticorpos Monoclonais/uso terapêutico , Antígeno B7-H1/antagonistas & inibidores , Carcinoma de Célula de Merkel/tratamento farmacológico , Antígenos de Histocompatibilidade Classe I/imunologia , Inibidores de Histona Desacetilases/uso terapêutico , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Neoplasias Cutâneas/tratamento farmacológico , Idoso , Idoso de 80 Anos ou mais , Anticorpos Monoclonais/imunologia , Antígeno B7-H1/genética , Antígeno B7-H1/imunologia , Carcinoma de Célula de Merkel/genética , Carcinoma de Célula de Merkel/imunologia , Regulação para Baixo/efeitos dos fármacos , Regulação para Baixo/genética , Regulação para Baixo/imunologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Resistencia a Medicamentos Antineoplásicos/imunologia , Feminino , Antígenos de Histocompatibilidade Classe I/genética , Antígenos de Histocompatibilidade Classe I/metabolismo , Inibidores de Histona Desacetilases/imunologia , Humanos , Imunoterapia/métodos , Masculino , Pessoa de Meia-Idade , Receptor de Morte Celular Programada 1/genética , Receptor de Morte Celular Programada 1/imunologia , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/imunologia
19.
Nat Commun ; 10(1): 1507, 2019 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-30944315

RESUMO

Exhaustion of cytotoxic effector natural killer (NK) and CD8+ T cells have important functions in the establishment of persistent viral infections, but how exhaustion is induced during chronic hepatitis C virus (HCV) infection remains poorly defined. Here we show, using the humanized C/OTg mice permissive for persistent HCV infection, that NK and CD8+ T cells become sequentially exhausted shortly after their transient hepatic infiltration and activation in acute HCV infection. HCV infection upregulates Qa-1 expression in hepatocytes, which ligates NKG2A to induce NK cell exhaustion. Antibodies targeting NKG2A or Qa-1 prevents NK exhaustion and promotes NK-dependent HCV clearance. Moreover, reactivated NK cells provide sufficient IFN-γ that helps rejuvenate polyclonal HCV CD8+ T cell response and clearance of HCV. Our data thus show that NKG2A serves as a critical checkpoint for HCV-induced NK exhaustion, and that NKG2A blockade sequentially boosts interdependent NK and CD8+ T cell functions to prevent persistent HCV infection.


Assuntos
Hepacivirus/imunologia , Hepatite C Crônica/imunologia , Células Matadoras Naturais/imunologia , Subfamília C de Receptores Semelhantes a Lectina de Células NK/imunologia , Animais , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Citocinas/imunologia , Modelos Animais de Doenças , Hepatite C Crônica/virologia , Hepatócitos/virologia , Antígenos de Histocompatibilidade Classe I/imunologia , Interferon gama/imunologia , Ativação Linfocitária/fisiologia , Proteínas de Membrana/imunologia , Camundongos , Distribuição Aleatória
20.
PLoS Pathog ; 15(4): e1007711, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-31034515

RESUMO

The human specific poxvirus molluscum contagiosum virus (MCV) produces skin lesions that can persist with minimal inflammation, suggesting that the virus has developed robust immune evasion strategies. However, investigations into the underlying mechanisms of MCV pathogenesis have been hindered by the lack of a model system to propagate the virus. Herein we demonstrate that MCV-encoded MC80 can disrupt MHC-I antigen presentation in human and mouse cells. MC80 shares moderate sequence-similarity with MHC-I and we find that it associates with components of the peptide-loading complex. Expression of MC80 results in ER-retention of host MHC-I and thereby reduced cell surface presentation. MC80 accomplishes this by engaging tapasin via its luminal domain, targeting it for ubiquitination and ER-associated degradation in a process dependent on the MC80 transmembrane region and cytoplasmic tail. Tapasin degradation is accompanied by a loss of TAP, which limits MHC-I access to cytosolic peptides. Our findings reveal a unique mechanism by which MCV undermines adaptive immune surveillance.


Assuntos
Apresentação do Antígeno/imunologia , Degradação Associada com o Retículo Endoplasmático , Retículo Endoplasmático/metabolismo , Antígenos de Histocompatibilidade Classe I/imunologia , Proteínas de Membrana Transportadoras/metabolismo , Molusco Contagioso/imunologia , Vírus do Molusco Contagioso/imunologia , Proteínas Virais/metabolismo , Membro 2 da Subfamília B de Transportadores de Cassetes de Ligação de ATP/genética , Membro 2 da Subfamília B de Transportadores de Cassetes de Ligação de ATP/metabolismo , Animais , Células Cultivadas , Humanos , Evasão da Resposta Imune , Camundongos , Molusco Contagioso/metabolismo , Molusco Contagioso/virologia , Linfócitos T Citotóxicos/imunologia , Proteínas Virais/genética
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