Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 264
Filtrar
Mais filtros

Tipo de documento
Intervalo de ano de publicação
1.
Immunity ; 55(10): 1909-1923.e6, 2022 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-36115338

RESUMO

Reciprocal interactions between host T helper cells and gut microbiota enforce local immunological tolerance and modulate extra-intestinal immunity. However, our understanding of antigen-specific tolerance to the microbiome is limited. Here, we developed a systematic approach to predict HLA class-II-specific epitopes using the humanized bacteria-originated T cell antigen (hBOTA) algorithm. We identified a diverse set of microbiome epitopes spanning all major taxa that are compatible with presentation by multiple HLA-II alleles. In particular, we uncovered an immunodominant epitope from the TonB-dependent receptor SusC that was universally recognized and ubiquitous among Bacteroidales. In healthy human subjects, SusC-reactive T cell responses were characterized by IL-10-dominant cytokine profiles, whereas in patients with active Crohn's disease, responses were associated with elevated IL-17A. Our results highlight the potential of targeted antigen discovery within the microbiome to reveal principles of tolerance and functional transitions during inflammation.


Assuntos
Doença de Crohn , Epitopos Imunodominantes , Linfócitos T CD4-Positivos , Epitopos de Linfócito T , Humanos , Interleucina-10 , Interleucina-17
2.
Immunity ; 51(4): 766-779.e17, 2019 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-31495665

RESUMO

Increasing evidence indicates CD4+ T cells can recognize cancer-specific antigens and control tumor growth. However, it remains difficult to predict the antigens that will be presented by human leukocyte antigen class II molecules (HLA-II), hindering efforts to optimally target them therapeutically. Obstacles include inaccurate peptide-binding prediction and unsolved complexities of the HLA-II pathway. To address these challenges, we developed an improved technology for discovering HLA-II binding motifs and conducted a comprehensive analysis of tumor ligandomes to learn processing rules relevant in the tumor microenvironment. We profiled >40 HLA-II alleles and showed that binding motifs were highly sensitive to HLA-DM, a peptide-loading chaperone. We also revealed that intratumoral HLA-II presentation was dominated by professional antigen-presenting cells (APCs) rather than cancer cells. Integrating these observations, we developed algorithms that accurately predicted APC ligandomes, including peptides from phagocytosed cancer cells. These tools and biological insights will enable improved HLA-II-directed cancer therapies.


Assuntos
Células Apresentadoras de Antígenos/imunologia , Linfócitos T CD4-Positivos/imunologia , Vacinas Anticâncer/imunologia , Mapeamento de Epitopos/métodos , Antígenos HLA/metabolismo , Antígenos de Histocompatibilidade Classe II/genética , Imunoterapia/métodos , Espectrometria de Massas/métodos , Neoplasias/terapia , Algoritmos , Alelos , Apresentação de Antígeno , Antígenos de Neoplasias/imunologia , Antígenos de Neoplasias/metabolismo , Conjuntos de Dados como Assunto , Antígenos HLA/genética , Antígenos HLA-D/metabolismo , Humanos , Neoplasias/imunologia , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas/genética , Software
3.
Brief Bioinform ; 25(2)2024 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-38493292

RESUMO

Computational predictors of immunogenic peptides, or epitopes, are traditionally built based on data from a broad range of pathogens without consideration for taxonomic information. While this approach may be reasonable if one aims to develop one-size-fits-all models, it may be counterproductive if the proteins for which the model is expected to generalize are known to come from a specific subset of phylogenetically related pathogens. There is mounting evidence that, for these cases, taxon-specific models can outperform generalist ones, even when trained with substantially smaller amounts of data. In this comment, we provide some perspective on the current state of taxon-specific modelling for the prediction of linear B-cell epitopes, and the challenges faced when building and deploying these predictors.


Assuntos
Peptídeos , Proteínas , Sequência de Aminoácidos , Epitopos de Linfócito B
4.
Brief Bioinform ; 25(2)2024 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-38487845

RESUMO

B cell epitope prediction methods are separated into linear sequence-based predictors and conformational epitope predictions that typically use the measured or predicted protein structure. Most linear predictions rely on the translation of the sequence to biologically based representations and the applications of machine learning on these representations. We here present CALIBER 'Conformational And LInear B cell Epitopes pRediction', and show that a bidirectional long short-term memory with random projection produces a more accurate prediction (test set AUC=0.789) than all current linear methods. The same predictor when combined with an Evolutionary Scale Modeling-2 projection also improves on the state of the art in conformational epitopes (AUC = 0.776). The inclusion of the graph of the 3D distances between residues did not increase the prediction accuracy. However, the long-range sequence information was essential for high accuracy. While the same model structure was applicable for linear and conformational epitopes, separate training was required for each. Combining the two slightly increased the linear accuracy (AUC 0.775 versus 0.768) and reduced the conformational accuracy (AUC = 0.769).


Assuntos
Epitopos de Linfócito B , Epitopos de Linfócito B/química , Conformação Molecular
5.
Brief Bioinform ; 24(1)2023 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-36611255

RESUMO

Accurate in silico prediction of conformational B-cell epitopes would lead to major improvements in disease diagnostics, drug design and vaccine development. A variety of computational methods, mainly based on machine learning approaches, have been developed in the last decades to tackle this challenging problem. Here, we rigorously benchmarked nine state-of-the-art conformational B-cell epitope prediction webservers, including generic and antibody-specific methods, on a dataset of over 250 antibody-antigen structures. The results of our assessment and statistical analyses show that all the methods achieve very low performances, and some do not perform better than randomly generated patches of surface residues. In addition, we also found that commonly used consensus strategies that combine the results from multiple webservers are at best only marginally better than random. Finally, we applied all the predictors to the SARS-CoV-2 spike protein as an independent case study, and showed that they perform poorly in general, which largely recapitulates our benchmarking conclusions. We hope that these results will lead to greater caution when using these tools until the biases and issues that limit current methods have been addressed, promote the use of state-of-the-art evaluation methodologies in future publications and suggest new strategies to improve the performance of conformational B-cell epitope prediction methods.


Assuntos
Epitopos de Linfócito B , Glicoproteína da Espícula de Coronavírus , Humanos , Biologia Computacional/métodos , Epitopos de Linfócito B/imunologia , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus/imunologia
6.
BMC Genomics ; 25(1): 507, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38778248

RESUMO

BACKGROUND: Alpha-papillomavirus 9 (α-9) is a member of the human papillomavirus (HPV) α genus, causing 75% invasive cervical cancers worldwide. The purpose of this study was to provide data for effective treatment of HPV-induced cervical lesions in Taizhou by analysing the genetic variation and antigenic epitopes of α-9 HPV E6 and E7. METHODS: Cervical exfoliated cells were collected for HPV genotyping. Positive samples of the α-9 HPV single type were selected for E6 and E7 gene sequencing. The obtained nucleotide sequences were translated into amino acid sequences (protein primary structure) using MEGA X, and positive selection sites of the amino acid sequences were evaluated using PAML. The secondary and tertiary structures of the E6 and E7 proteins were predicted using PSIPred, SWISS-MODEL, and PyMol. Potential T/B-cell epitopes were predicted by Industrial Engineering Database (IEDB). RESULTS: From 2012 to 2023, α-9 HPV accounted for 75.0% (7815/10423) of high-risk HPV-positive samples in Taizhou, both alone and in combination with other types. Among these, single-type-positive samples of α-9 HPV were selected, and the entire E6 and E7 genes were sequenced, including 298 HPV16, 149 HPV31, 185 HPV33, 123 HPV35, 325 HPV52, and 199 HPV58 samples. Compared with reference sequences, 34, 12, 10, 2, 17, and 17 nonsynonymous nucleotide mutations were detected in HPV16, 31, 33, 35, 52, and 58, respectively. Among all nonsynonymous nucleotide mutations, 19 positive selection sites were selected, which may have evolutionary significance in rendering α-9 HPV adaptive to its environment. Immunoinformatics predicted 57 potential linear and 59 conformational B-cell epitopes, many of which are also predicted as CTL epitopes. CONCLUSION: The present study provides almost comprehensive data on the genetic variations, phylogenetics, positive selection sites, and antigenic epitopes of α-9 HPV E6 and E7 in Taizhou, China, which will be helpful for local HPV therapeutic vaccine development.


Assuntos
Proteínas Oncogênicas Virais , Filogenia , China , Humanos , Proteínas Oncogênicas Virais/genética , Proteínas Oncogênicas Virais/imunologia , Feminino , Proteínas E7 de Papillomavirus/genética , Proteínas E7 de Papillomavirus/imunologia , Alphapapillomavirus/genética , Alphapapillomavirus/imunologia , Epitopos de Linfócito B/imunologia , Epitopos de Linfócito B/genética , Epitopos/imunologia , Epitopos/genética , Epitopos de Linfócito T/imunologia , Epitopos de Linfócito T/genética , Infecções por Papillomavirus/virologia , Sequência de Aminoácidos
7.
Brief Bioinform ; 23(4)2022 07 18.
Artigo em Inglês | MEDLINE | ID: mdl-35794711

RESUMO

In 2014, the Immune Epitope Database automated benchmark was created to compare the performance of the MHC class I binding predictors. However, this is not a straightforward process due to the different and non-standardized outputs of the methods. Additionally, some methods are more restrictive regarding the HLA alleles and epitope sizes for which they predict binding affinities, while others are more comprehensive. To address how these problems impacted the ranking of the predictors, we developed an approach to assess the reliability of different metrics. We found that using percentile-ranked results improved the stability of the ranks and allowed the predictors to be reliably ranked despite not being evaluated on the same data. We also found that given the rate new data are incorporated into the benchmark, a new method must wait for at least 4 years to be ranked against the pre-existing methods. The best-performing tools with statistically indistinguishable scores in this benchmark were NetMHCcons, NetMHCpan4.0, ANN3.4, NetMHCpan3.0 and NetMHCpan2.8. The results of this study will be used to improve the evaluation and display of benchmark performance. We highly encourage anyone working on MHC binding predictions to participate in this benchmark to get an unbiased evaluation of their predictors.


Assuntos
Benchmarking , Alelos , Epitopos , Ligação Proteica , Reprodutibilidade dos Testes
8.
Brief Bioinform ; 23(5)2022 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-35849093

RESUMO

The coronavirus disease 2019 pandemic has alerted people of the threat caused by viruses. Vaccine is the most effective way to prevent the disease from spreading. The interaction between antibodies and antigens will clear the infectious organisms from the host. Identifying B-cell epitopes is critical in vaccine design, development of disease diagnostics and antibody production. However, traditional experimental methods to determine epitopes are time-consuming and expensive, and the predictive performance using the existing in silico methods is not satisfactory. This paper develops a general framework to predict variable-length linear B-cell epitopes specific for human-adapted viruses with machine learning approaches based on Protvec representation of peptides and physicochemical properties of amino acids. QR decomposition is incorporated during the embedding process that enables our models to handle variable-length sequences. Experimental results on large immune epitope datasets validate that our proposed model's performance is superior to the state-of-the-art methods in terms of AUROC (0.827) and AUPR (0.831) on the testing set. Moreover, sequence analysis also provides the results of the viral category for the corresponding predicted epitopes with high precision. Therefore, this framework is shown to reliably identify linear B-cell epitopes of human-adapted viruses given protein sequences and could provide assistance for potential future pandemics and epidemics.


Assuntos
COVID-19 , Vírus , Aminoácidos , Mapeamento de Epitopos/métodos , Epitopos de Linfócito B , Humanos , Aprendizado de Máquina , Peptídeos/química
9.
Brief Bioinform ; 23(5)2022 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-35998895

RESUMO

Linear B-cell epitopes have a prominent role in the development of peptide-based vaccines and disease diagnosis. High variability in the length of these epitopes is a major reason for low accuracy in their prediction. Most of the B-cell epitope prediction methods considered fixed length of epitope sequences and achieved good accuracy. Though a number of tools are available for the prediction of flexible length linear B-cell epitopes with reasonable accuracy, further improvement in the prediction performance is still expected. Thus, here we made an attempt to analyze the performance of machine learning approaches (MLA) with 18 different amino acid encoding schemes in the prediction of flexible length linear B-cell epitopes. We considered B-cell epitope sequences of variable lengths (11-56 amino acids) from well-established public resources. The performances of machine learning algorithms with the encoded epitope sequence datasets were evaluated. Besides, the feasible combinations of encoding schemes were also explored and analyzed. The results revealed that amino-acid composition (AC) and distribution component of composition-transition-distribution encoding schemes are suitable for heterogeneous epitope data, whereas amino-acid-anchoring-pair-composition (APC), dipeptide-composition and amino-acids-pair-propensity-scale (APP) are more appropriate for homogeneous data. Further, two combinations of peptide encoding schemes, i.e. APC + AC and APC + APP with random forest classifier were identified to have improved performance over the state-of-the-art tools for flexible length linear B-cell epitope prediction. The study also revealed better performance of random forest over other considered MLAs in the prediction of flexible length linear B-cell epitopes.


Assuntos
Epitopos de Linfócito B , Vacinas , Aminoácidos/genética , Dipeptídeos , Peptídeos/química
10.
Brief Bioinform ; 23(2)2022 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-35226074

RESUMO

The development of autoimmune diseases following SARS-CoV-2 infection, including multisystem inflammatory syndrome, has been reported, and several mechanisms have been suggested, including molecular mimicry. We developed a scalable, comparative immunoinformatics pipeline called cross-reactive-epitope-search-using-structural-properties-of-proteins (CRESSP) to identify cross-reactive epitopes between a collection of SARS-CoV-2 proteomes and the human proteome using the structural properties of the proteins. Overall, by searching 4 911 245 proteins from 196 352 SARS-CoV-2 genomes, we identified 133 and 648 human proteins harboring potential cross-reactive B-cell and CD8+ T-cell epitopes, respectively. To demonstrate the robustness of our pipeline, we predicted the cross-reactive epitopes of coronavirus spike proteins, which were recognized by known cross-neutralizing antibodies. Using single-cell expression data, we identified PARP14 as a potential target of intermolecular epitope spreading between the virus and human proteins. Finally, we developed a web application (https://ahs2202.github.io/3M/) to interactively visualize our results. We also made our pipeline available as an open-source CRESSP package (https://pypi.org/project/cressp/), which can analyze any two proteomes of interest to identify potentially cross-reactive epitopes between the proteomes. Overall, our immunoinformatic resources provide a foundation for the investigation of molecular mimicry in the pathogenesis of autoimmune and chronic inflammatory diseases following COVID-19.


Assuntos
Biologia Computacional/métodos , Epitopos/química , Epitopos/imunologia , SARS-CoV-2/imunologia , Software , Proteínas Virais/química , Proteínas Virais/imunologia , Algoritmos , Reações Cruzadas/imunologia , Epitopos de Linfócito B , Epitopos de Linfócito T , Antígenos de Histocompatibilidade Classe I/química , Antígenos de Histocompatibilidade Classe I/imunologia , Antígenos de Histocompatibilidade Classe II/química , Antígenos de Histocompatibilidade Classe II/imunologia , Modelos Moleculares , Mimetismo Molecular , Redes Neurais de Computação , Proteoma , Proteômica/métodos , Relação Estrutura-Atividade , Navegador
11.
J Med Virol ; 96(9): e29923, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39291820

RESUMO

Arthropod-borne viruses, such as dengue virus (DENV), pose significant global health threats, with DENV alone infecting around 400 million people annually and causing outbreaks beyond endemic regions. This study aimed to enhance serological diagnosis and discover new drugs by identifying immunogenic protein regions of DENV. Utilizing a comprehensive approach, the study focused on peptides capable of distinguishing DENV from other flavivirus infections through serological analyses. Over 200 patients with confirmed arbovirus infection were profiled using high-density pan flavivirus peptide arrays comprising 6253 peptides and the computational method matrix of local coupling energy (MLCE). Twenty-four peptides from nonstructural and structural viral proteins were identified as specifically recognized by individuals with DENV infection. Six peptides were confirmed to distinguish DENV from Zika virus (ZIKV), West Nile virus (WNV), Yellow Fever virus (YFV), Usutu virus (USUV), and Chikungunya virus (CHIKV) infections, as well as healthy controls. Moreover, the combination of two immunogenic peptides emerged as a potential serum biomarker for DENV infection. These peptides, mapping to highly accessible regions on protein structures, show promise for diagnostic and prophylactic strategies against flavivirus infections. The described methodology holds broader applicability in the serodiagnosis of infectious diseases.


Assuntos
Infecções por Flavivirus , Flavivirus , Análise Serial de Proteínas , Humanos , Infecções por Flavivirus/diagnóstico , Infecções por Flavivirus/imunologia , Flavivirus/imunologia , Análise Serial de Proteínas/métodos , Peptídeos/imunologia , Desenvolvimento de Vacinas , Biologia Computacional/métodos , Dengue/diagnóstico , Dengue/imunologia , Dengue/sangue , Vírus da Dengue/imunologia , Vírus da Dengue/genética , Ensaios de Triagem em Larga Escala/métodos , Testes Sorológicos/métodos , Biomarcadores/sangue , Proteínas Virais/imunologia , Adulto , Anticorpos Antivirais/sangue , Pessoa de Meia-Idade , Masculino , Feminino , Zika virus/imunologia
12.
Virol J ; 21(1): 152, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38970084

RESUMO

BACKGROUND: High-risk human papillomavirus (HR-HPV) infection is an important factor for the development of cervical cancer. HPV18 is the second most common HR-HPV after HPV16. METHODS: In this study, MEGA11 software was used to analyze the variation and phylogenetic tree of HPV18 E6-E7 and L1 genes. The selective pressure to E6, E7 and L1 genes was estimated using pamlX. In addition, the B cell epitopes of L1 amino acid sequences and T cell epitopes of E6-E7 amino acid sequences in HPV18 were predicted by ABCpred server and IEDB website, respectively. RESULTS: A total of 9 single nucleotide variants were found in E6-E7 sequences, of which 2 were nonsynonymous variants and 7 were synonymous variants. Twenty single nucleotide variants were identified in L1 sequence, including 11 nonsynonymous variants and 9 synonymous variants. Phylogenetic analysis showed that E6-E7 and L1 sequences were all distributed in A lineage. In HPV18 E6, E7 and L1 sequences, no positively selected site was found. The nonconservative substitution R545C in L1 affected hypothetical B cell epitope. Two nonconservative substitutions, S82A in E6, and R53Q in E7, impacted multiple hypothetical T cell epitopes. CONCLUSION: The sequence variation data of HPV18 may lay a foundation for the virus diagnosis, further study of cervical cancer and vaccine design in central China.


Assuntos
Variação Genética , Papillomavirus Humano 18 , Proteínas Oncogênicas Virais , Proteínas E7 de Papillomavirus , Filogenia , Proteínas Oncogênicas Virais/genética , China , Humanos , Papillomavirus Humano 18/genética , Papillomavirus Humano 18/classificação , Proteínas E7 de Papillomavirus/genética , Proteínas do Capsídeo/genética , Feminino , Epitopos de Linfócito T/genética , Infecções por Papillomavirus/virologia , Proteínas Repressoras/genética , Epitopos de Linfócito B/genética , Proteínas de Ligação a DNA
13.
Rev Med Virol ; 33(5): e2463, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37291746

RESUMO

The human papillomavirus (HPV) represents the most prevalent sexually transmitted infectious agent worldwide. HPV penetrates the epithelium through microlesions and establishes an infectious focus that can lead to the development of cervical cancer. Prophylactic HPV vaccines are available, but do not affect already-established infections. Using in silico prediction tools is a promising strategy for identifying and selecting vaccine candidate T cell epitopes. An advantage of this strategy is that epitopes can be selected according to the degree of conservation within a group of antigenic proteins. This makes achieving comprehensive genotypic coverage possible with a small set of epitopes. Therefore, this paper revises the general characteristics of HPV biology and the current knowledge on developing therapeutic peptide vaccines against HPV-related infections and cervical cancer.


Assuntos
Infecções por Papillomavirus , Vacinas contra Papillomavirus , Neoplasias do Colo do Útero , Feminino , Humanos , Neoplasias do Colo do Útero/prevenção & controle , Papillomavirus Humano , Infecções por Papillomavirus/prevenção & controle , Vacinas contra Papillomavirus/uso terapêutico , Epitopos
14.
Semin Immunol ; 50: 101418, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-33131981

RESUMO

Epitopes, in the context of T cell recognition, are short peptides typically derived by antigen processing, and presented on the cell surface bound to MHC molecules (HLA molecules in humans) for TCR scrutiny. The identification of epitopes is a context-dependent process, with consideration given to, for example, the source pathogen and protein, the host organism, and state of the immune reaction (e.g., following natural infection, vaccination, etc.). In the following review, we consider the various approaches used to define T cell epitopes, including both bioinformatic and experimental approaches, and discuss the concepts of immunodominance and immunoprevalence. We also discuss HLA polymorphism and epitope restriction, and the resulting impact on the identification of, and potential population coverage afforded by, epitopes or epitope-based vaccines. Finally, some examples of the practical application of T cell epitope identification are provided, showing how epitopes have been valuable for deriving novel immunological insights in the context of the immune response to various pathogens and allergens.


Assuntos
Mapeamento de Epitopos/métodos , Epitopos de Linfócito T/genética , Epitopos Imunodominantes/metabolismo , Linfócitos T/imunologia , Vacinas/imunologia , Animais , Biologia Computacional , Epitopos de Linfócito T/metabolismo , Antígenos HLA/genética , Antígenos HLA/metabolismo , Humanos , Imunoensaio , Epitopos Imunodominantes/genética , Polimorfismo Genético , Ligação Proteica
15.
Int J Mol Sci ; 25(11)2024 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-38891974

RESUMO

Tetanus disease, caused by C. tetani, starts with wounds or mucous layer contact. Prevented by vaccination, the lack of booster shots throughout life requires prophylactic treatment in case of accidents. The incidence of tetanus is high in underdeveloped countries, requiring the administration of antitetanus antibodies, usually derived from immunized horses or humans. Heterologous sera represent risks such as serum sickness. Human sera can carry unknown viruses. In the search for human monoclonal antibodies (mAbs) against TeNT (Tetanus Neurotoxin), we previously identified a panel of mAbs derived from B-cell sorting, selecting two nonrelated ones that binded to the C-terminal domain of TeNT (HCR/T), inhibiting its interaction with the cellular receptor ganglioside GT1b. Here, we present the results of cellular assays and molecular docking tools. TeNT internalization in neurons is prevented by more than 50% in neonatal rat spinal cord cells, determined by quantitative analysis of immunofluorescence punctate staining of Alexa Fluor 647 conjugated to TeNT. We also confirmed the mediator role of the Synaptic Vesicle Glycoprotein II (SV2) in TeNT endocytosis. The molecular docking assays to predict potential TeNT epitopes showed the binding of both antibodies to the HCR/T domain. A higher incidence was found between N1153 and W1297 when evaluating candidate residues for conformational epitope.


Assuntos
Anticorpos Monoclonais , Endocitose , Simulação de Acoplamento Molecular , Neurônios , Toxina Tetânica , Animais , Ratos , Neurônios/metabolismo , Humanos , Anticorpos Monoclonais/imunologia , Toxina Tetânica/imunologia , Toxina Tetânica/metabolismo , Tétano/prevenção & controle , Tétano/imunologia , Epitopos/imunologia , Gangliosídeos/imunologia , Gangliosídeos/metabolismo , Células Cultivadas , Simulação por Computador , Metaloendopeptidases
16.
Cancer Immunol Immunother ; 72(7): 2375-2392, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36943460

RESUMO

Immunotherapeutic strategies aimed at enhancing tumor cell killing by tumor-specific T cells hold great potential for reducing tumor burden and prolonging survival of cancer patients. Although many potential tumor antigens have been described, identifying relevant targets when designing anti-cancer vaccines or targeted cell therapies remains a challenge. To identify novel, potentially immunogenic candidate tumor antigens, we performed integrated tumor transcriptomic, seromic, and proteomic analyses of high grade serous ovarian cancer (HGSC) patient tumor samples. We identified tumor neo-antigens and over-expressed antigens using whole exome and RNA sequencing and examined these in relation to patient-matched auto-antibody repertoires. Focusing on MHC class I epitopes recognized by CD8+ T cells, HLA-binding epitopes were identified or predicted from the highly expressed, mutated, or auto-antibody target antigen, or MHC-associated peptides (MAPs). Recognition of candidate antigenic peptides was assessed within the tumor-infiltrating T lymphocyte (TIL) population expanded from each patient. Known tumor-associated antigens (TAA) and cancer/testis antigens (CTA) were commonly found in the auto-antibody and MAP repertoires and CD8+ TILs recognizing epitopes from these antigens were detected, although neither expression level nor the presence of auto-antibodies correlated with TIL recognition. Auto-antibodies against tumor-mutated antigens were found in most patients, however, no TIL recognition of the highest predicted affinity neo-epitopes was detected. Using high expression level, auto-antibody recognition, and epitope prediction algorithms, we identified epitopes in 5 novel antigens (MOB1A, SOCS3, TUBB, PRKAR1A, CCDC6) recognized by HGSC patient TILs. Furthermore, selection of epitopes from the MAP repertoire identified 5 additional targets commonly recognized by multiple patient TILs. We find that the repertoire of TIL specificities includes recognition of highly expressed and immunogenic self-antigens that are processed and presented by tumors. These results indicate an ongoing autoimmune response against a range of self-antigens targeted by HGSC TILs.


Assuntos
Linfócitos do Interstício Tumoral , Neoplasias Ovarianas , Masculino , Humanos , Feminino , Epitopos/metabolismo , Linfócitos T CD8-Positivos , Proteômica , Multiômica , Antígenos de Neoplasias , Peptídeos , Autoantígenos , Epitopos de Linfócito T
17.
Brief Bioinform ; 22(4)2021 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-33346826

RESUMO

The prediction of epitope recognition by T-cell receptors (TCRs) has seen many advancements in recent years, with several methods now available that can predict recognition for a specific set of epitopes. However, the generic case of evaluating all possible TCR-epitope pairs remains challenging, mainly due to the high diversity of the interacting sequences and the limited amount of currently available training data. In this work, we provide an overview of the current state of this unsolved problem. First, we examine appropriate validation strategies to accurately assess the generalization performance of generic TCR-epitope recognition models when applied to both seen and unseen epitopes. In addition, we present a novel feature representation approach, which we call ImRex (interaction map recognition). This approach is based on the pairwise combination of physicochemical properties of the individual amino acids in the CDR3 and epitope sequences, which provides a convolutional neural network with the combined representation of both sequences. Lastly, we highlight various challenges that are specific to TCR-epitope data and that can adversely affect model performance. These include the issue of selecting negative data, the imbalanced epitope distribution of curated TCR-epitope datasets and the potential exchangeability of TCR alpha and beta chains. Our results indicate that while extrapolation to unseen epitopes remains a difficult challenge, ImRex makes this feasible for a subset of epitopes that are not too dissimilar from the training data. We show that appropriate feature engineering methods and rigorous benchmark standards are required to create and validate TCR-epitope predictive models.


Assuntos
Regiões Determinantes de Complementaridade , Epitopos de Linfócito T , Modelos Genéticos , Modelos Imunológicos , Receptores de Antígenos de Linfócitos T alfa-beta , Animais , Regiões Determinantes de Complementaridade/genética , Regiões Determinantes de Complementaridade/imunologia , Epitopos de Linfócito T/genética , Epitopos de Linfócito T/imunologia , Humanos , Macaca mulatta , Camundongos , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Receptores de Antígenos de Linfócitos T alfa-beta/imunologia
18.
Brief Bioinform ; 22(2): 1309-1323, 2021 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-33285567

RESUMO

The recurrent and recent global outbreak of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has turned into a global concern which has infected more than 42 million people all over the globe, and this number is increasing in hours. Unfortunately, no vaccine or specific treatment is available, which makes it more deadly. A vaccine-informatics approach has shown significant breakthrough in peptide-based epitope mapping and opens the new horizon in vaccine development. In this study, we have identified a total of 15 antigenic peptides [including thymus cells (T-cells) and bone marrow or bursa-derived cells] in the surface glycoprotein (SG) of SARS-CoV-2 which is nontoxic and nonallergenic in nature, nonallergenic, highly antigenic and non-mutated in other SARS-CoV-2 virus strains. The population coverage analysis has found that cluster of differentiation 4 (CD4+) T-cell peptides showed higher cumulative population coverage over cluster of differentiation 8 (CD8+) peptides in the 16 different geographical regions of the world. We identified 12 peptides ((LTDEMIAQY, WTAGAAAYY, WMESEFRVY, IRASANLAA, FGAISSVLN, VKQLSSNFG, FAMQMAYRF, FGAGAALQI, YGFQPTNGVGYQ, LPDPSKPSKR, QTQTNSPRRARS and VITPGTNTSN) that are $80\hbox{--} 90\%$ identical with experimentally determined epitopes of SARS-CoV, and this will likely be beneficial for a quick progression of the vaccine design. Moreover, docking analysis suggested that the identified peptides are tightly bound in the groove of human leukocyte antigen molecules which can induce the T-cell response. Overall, this study allows us to determine potent peptide antigen targets in the SG on intuitive grounds, which opens up a new horizon in the coronavirus disease (COVID-19) research. However, this study needs experimental validation by in vitro and in vivo.


Assuntos
COVID-19/prevenção & controle , Epitopos de Linfócito B/imunologia , Epitopos de Linfócito T/imunologia , SARS-CoV-2/imunologia , Vacinas de Subunidades Antigênicas/imunologia , Sequência de Aminoácidos , COVID-19/imunologia , Biologia Computacional , Epitopos de Linfócito B/química , Epitopos de Linfócito T/química , Antígenos HLA/química , Humanos , Simulação de Acoplamento Molecular , Vacinas de Subunidades Antigênicas/química
19.
Virol J ; 20(1): 217, 2023 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-37759219

RESUMO

BACKGROUND: Persistent high-risk human papillomavirus (HR-HPV) infection is an important factor in the development of cervical cancer, and human papillomavirus type 16 (HPV-16) is the most common HR-HPV type worldwide. The oncogenic potential of HPV-16 is closely related to viral sequence variation. METHODS: In order to clarify the variant characteristics of HPV-16 E6 and E7 genes in central China, E6 and E7 sequences of 205 HPV-16 positive samples were amplified by polymerase chain reaction. PCR products of E6 and E7 genes were further sequenced and subjected to variation analysis, phylogenetic analysis, selective pressure analysis and B-cell epitope prediction. RESULTS: Twenty-six single nucleotide variants were observed in E6 sequence, including 21 non-synonymous and 5 synonymous variants. Twelve single nucleotide variants were identified in E7 sequence, including 6 non-synonymous and 6 synonymous variants. Four new variants were found. Furthermore, nucleotide variation A647G (N29S) in E7 was significantly related to the higher risk of HSIL and cervical cancer. Phylogenetic analysis showed that the E6 and E7 sequences were all distributed in A lineage. No positively selected site was found in HPV-16 E6 and E7 sequences. Non-conservative substitutions in E6, H31Y, D32N, D32E, I34M, L35V, E36Q, L45P, N65S and K75T, affected multiple B-cell epitopes. However, the variation of E7 gene had little impact on the corresponding B-cell epitopes (score < 0.85). CONCLUSION: HPV-16 E6 and E7 sequences variation data may contribute to HR-HPV prevention and vaccine development in Jingzhou, central China.


Assuntos
Papillomavirus Humano 16 , Infecções por Papillomavirus , Neoplasias do Colo do Útero , Feminino , Humanos , China/epidemiologia , Epitopos de Linfócito B/genética , Variação Genética , Papillomavirus Humano 16/genética , Papillomavirus Humano , Nucleotídeos , Infecções por Papillomavirus/epidemiologia , Filogenia , Neoplasias do Colo do Útero/epidemiologia
20.
Arch Microbiol ; 205(12): 380, 2023 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-37955744

RESUMO

Nipah virus, a zoonotic virus from the family Paramyxoviridae has led to significant loss of lives till date with the most recent outbreak in India reported in Kerala. The virus has a considerably high mortality rate along with lack of characteristic symptoms which results in the delay of the virus detection. No specific vaccine is available for the virus although monoclonal antibody treatment has been seen to be effective along with favipiravir. The high mortality and complications caused by the virus underscores the necessity to develop alternative modes of vaccination. One such method has been designed in this study using peptide cocktail consisting of the immunologically important epitopes for use as vaccine. The human leucocytic antigens that are used for the study were analyzed for their presence in various ethnic Indian populations. This study may serve as a new avenue for development of more efficient peptide cocktail vaccines in recent future based on the population genetics and ethnicity.


Assuntos
Vírus Nipah , Humanos , Vírus Nipah/genética , Vacinas de Subunidades Antigênicas , Epitopos/genética , Peptídeos , Estudos Epidemiológicos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA