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1.
Bioinformatics ; 40(3)2024 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-38449295

RESUMO

MOTIVATION: Antibodies are proteins that the immune system produces in response to foreign pathogens. Designing antibodies that specifically bind to antigens is a key step in developing antibody therapeutics. The complementarity determining regions (CDRs) of the antibody are mainly responsible for binding to the target antigen, and therefore must be designed to recognize the antigen. RESULTS: We develop an antibody design model, AbFlex, that exhibits state-of-the-art performance in terms of structure prediction accuracy and amino acid recovery rate. Furthermore, >38% of newly designed antibody models are estimated to have better binding energies for their antigens than wild types. The effectiveness of the model is attributed to two different strategies that are developed to overcome the difficulty associated with the scarcity of antibody-antigen complex structure data. One strategy is to use an equivariant graph neural network model that is more data-efficient. More importantly, a new data augmentation strategy based on the flexible definition of CDRs significantly increases the performance of the CDR prediction model. AVAILABILITY AND IMPLEMENTATION: The source code and implementation are available at https://github.com/wsjeon92/AbFlex.


Assuntos
Complexo Antígeno-Anticorpo , Regiões Determinantes de Complementaridade , Regiões Determinantes de Complementaridade/química , Regiões Determinantes de Complementaridade/metabolismo , Sequência de Aminoácidos , Modelos Moleculares , Complexo Antígeno-Anticorpo/química , Antígenos
2.
Cancer Immunol Immunother ; 73(2): 24, 2024 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-38280010

RESUMO

Tumor-infiltrating lymphocytes (TILs) play a key role in regulating the host immune response and shaping tumor microenvironment. It has been previously shown that T cell infiltration in penile tumors was associated with clinical outcomes. However, few studies have reported the T cell receptor (TCR) repertoire in patients with penile cancer. In the present study, we evaluated the TCR repertoires in tumor and adjacent normal tissues from 22 patients with penile squamous cell carcinoma (PSCC). Analysis of the T cell receptor beta-variable (TRBV) and joining (TRBJ) genes usage and analysis of complementarity determining region 3 (CDR3) length distribution did not show significant differences between tumor and matched normal tissues. Moreover, analysis of the median Jaccard index indicated a limited overlap of TCR repertoire between these groups. Compared with normal tissues, a significantly lower diversity and higher clonality of TCR repertoire was observed in tumor samples, which was associated with clinical characteristics. Further analysis of transcriptional profiles demonstrated that tumor samples with high clonality showed increased expression of genes associated with CD8 + T cells. In addition, we analyzed the TCR repertoire of CD4 + T cells and CD8 + T cells isolated from tumor tissues. We identified that expanded clonotypes were predominantly in the CD8 + T cell compartment, which presented with an exhausted phenotype. Overall, we comprehensively compared TCR repertoire between penile tumor and normal tissues and demonstrated the presence of distinct T cell immune microenvironments in patients with PSCC.


Assuntos
Carcinoma de Células Escamosas , Neoplasias Penianas , Masculino , Humanos , Receptores de Antígenos de Linfócitos T , Neoplasias Penianas/genética , Neoplasias Penianas/metabolismo , Regiões Determinantes de Complementaridade/metabolismo , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Linfócitos T CD8-Positivos , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/metabolismo , Microambiente Tumoral
3.
Sci Rep ; 13(1): 17714, 2023 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-37853083

RESUMO

Thymic T cell development comprises T cell receptor (TCR) recombination and assessment of TCR avidity towards self-peptide-MHC complexes presented by antigen-presenting cells. Self-reactivity may lead to negative selection, or to agonist selection and differentiation into unconventional lineages such as regulatory T cells and CD8[Formula: see text] T cells. To explore the effect of the adaptive immune receptor repertoire on thymocyte developmental decisions, we performed single cell adaptive immune receptor repertoire sequencing (scAIRR-seq) of thymocytes from human young paediatric thymi and blood. Thymic PDCD1+ cells, a putative CD8[Formula: see text] T cell precursor population, exhibited several TCR features previously associated with thymic and peripheral ZNF683+ CD8[Formula: see text] T cells, including enrichment of large and positively charged complementarity-determining region 3 (CDR3) amino acids. Thus, the TCR repertoire may partially explain the decision between conventional vs. agonist selected thymocyte differentiation, an aspect of importance for the development of therapies for patients with immune-mediated diseases.


Assuntos
Receptores de Antígenos de Linfócitos T , Timócitos , Humanos , Criança , Receptores de Antígenos de Linfócitos T/metabolismo , Timócitos/metabolismo , Timo/metabolismo , Linfócitos T Reguladores , Regiões Determinantes de Complementaridade/genética , Regiões Determinantes de Complementaridade/metabolismo , Diferenciação Celular , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo
4.
Nat Commun ; 14(1): 4732, 2023 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-37563127

RESUMO

Chimeric antigen receptor (CAR)-T cell therapy is rapidly advancing as cancer treatment, however, designing an optimal CAR remains challenging. A single-chain variable fragment (scFv) is generally used as CAR targeting moiety, wherein the complementarity-determining regions (CDRs) define its specificity. We report here that the CDR loops can cause CAR clustering, leading to antigen-independent tonic signalling and subsequent CAR-T cell dysfunction. We show via CARs incorporating scFvs with identical framework and varying CDR sequences that CARs may cluster on the T cell surface, which leads to antigen-independent CAR-T cell activation, characterized by increased cell size and interferon (IFN)-γ secretion. This results in CAR-T cell exhaustion, activation-induced cell death and reduced responsiveness to target-antigen-expressing tumour cells. CDR mutagenesis confirms that the CAR-clustering is mediated by CDR-loops. In summary, antigen-independent tonic signalling can be induced by CDR-mediated CAR clustering, which could not be predicted from the scFv sequences, but could be tested for by evaluating the activity of unstimulated CAR-T cells.


Assuntos
Regiões Determinantes de Complementaridade , Anticorpos de Cadeia Única , Regiões Determinantes de Complementaridade/genética , Regiões Determinantes de Complementaridade/metabolismo , Linfócitos T , Imunoterapia Adotiva/métodos , Transdução de Sinais , Linhagem Celular Tumoral , Receptores de Antígenos de Linfócitos T/metabolismo
5.
Biotechnol Adv ; 64: 108120, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36764335

RESUMO

In contrast to other species, cattle possess exceptional antibodies with ultra-long complementarity-determining regions (ulCDRs) that can consist of 40-70 amino acids. The bovine ulCDR is folded into a stalk and a disulfide-rich knob domain. The binding to the antigen is via the 3-6 kDa knob. There exists an immense sequence and structural diversity in the knob that enables binding to different antigens. Here we summarize the current knowledge of the ulCDR structure and provide an overview of the approaches to discover ulCDRs against novel antigens. Furthermore, we outline protein engineering approaches inspired by the natural ulCDRs. Finally, we discuss the enormous potential of using isolated bovine knobs, also named picobodies, as the smallest antigen-binding domains derived from natural antibodies.


Assuntos
Anticorpos , Regiões Determinantes de Complementaridade , Bovinos , Animais , Regiões Determinantes de Complementaridade/química , Regiões Determinantes de Complementaridade/metabolismo , Anticorpos/genética , Anticorpos/química , Antígenos , Aminoácidos
6.
Allergy ; 78(1): 270-282, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36005389

RESUMO

BACKGROUND: Apart from Ni2+ , Co2+ , and Pd2+ ions commonly trigger T cell-mediated allergic contact dermatitis. However, in vitro frequencies of metal-specific T cells and the mechanisms of antigen recognition remain unclear. METHODS: Here, we utilized a CD154 upregulation assay to quantify Ni2+ -, Co2+ -, and Pd2+ -specific CD4+ T cells in peripheral blood mononuclear cells (PBMC). Involved αß T cell receptor (TCR) repertoires were analyzed by high-throughput sequencing. RESULTS: Peripheral blood mononuclear cells incubation with NiSO4 , CoCl2 , and PdCl2 increased frequencies of CD154 + CD4+ memory T cells that peaked at ~400 µM. Activation was TCR-mediated as shown by the metal-specific restimulation of T cell clones. Most abundant were Pd2+ -specific T cells (mean 3.5%, n = 19), followed by Co2+ - and Ni2+ -specific cells (0.6%, n = 18 and 0.3%, n = 20) in both allergic and non-allergic individuals. A strong overrepresentation of the gene segment TRAV9-2 was unique for Ni2+ -specific TCR (28% of TCR) while Co2+ and Pd2+ -specific TCR favorably expressed TRAV2 (8%) and the TRBV4 gene segment family (21%), respectively. As a second, independent mechanism of metal ion recognition, all analyzed metal-specific TCR showed a common overrepresentation of a histidine in the complementarity determining region 3 (CDR3; 15% of α-chains, 34% of ß-chains). The positions of the CDR3 histidine among metal-specific TCR mirrored those in random repertoires and were conserved among cross-reactive clonotypes. CONCLUSIONS: Induced CD154 expression allows a fast and comprehensive detection of Ni2+ -, Co2+ -, and Pd2+ -specific CD4+ T cells. Distinct TCR repertoire features underlie the frequent activation and cross-reactivity of human metal-specific T cells.


Assuntos
Linfócitos T CD4-Positivos , Receptores de Antígenos de Linfócitos T alfa-beta , Humanos , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Leucócitos Mononucleares/metabolismo , Histidina/metabolismo , Regiões Determinantes de Complementaridade/genética , Regiões Determinantes de Complementaridade/metabolismo
7.
Cell Prolif ; 55(11): e13311, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35929064

RESUMO

OBJECTIVES: This study investigated the characteristics of the immune repertoire in normal Chinese individuals of different ages. MATERIALS AND METHODS: In this study, all seven receptor chains from both B and T cells in peripheral blood of 16 normal Chinese individuals from two age groups were analyzed using high-throughput sequencing and dimer-avoided multiplex PCR amplification. Normal in this study is defined as no chronic, infectious or autoimmune disease within 6 months prior to blood draw. RESULTS: We found that compared with the younger group, the clonal expression of T-cell receptor repertoire increased in the older group, while diversity decreased. In addition, we found that the T-cell receptor repertoire was more significantly affected by age than the B-cell receptor repertoire, including significant differences in the use of the unique TCR-alpha and TCR-beta V-J gene combinations, in the two groups of normal participants. We further analyzed the degree of complementarity determining region 3 sequence sharing between the two groups, and found shared TCR-alpha, TCR-gamma, immunoglobulin-kappa and immunoglobulin-lambda chain complementarity determining region 3 sequences in all subjects. CONCLUSION: Taken together, our study gives us a better understanding of the immune repertoire of different normal Chinese people, and these results can be applied to the treatment of age-related diseases. Immune repertoire analysis also allows us to observe participant's wellness, aiding in early-stage diagnosis.


Assuntos
Regiões Determinantes de Complementaridade , Receptores de Antígenos de Linfócitos T alfa-beta , Humanos , Regiões Determinantes de Complementaridade/genética , Regiões Determinantes de Complementaridade/metabolismo , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Linfócitos T/metabolismo , Sequenciamento de Nucleotídeos em Larga Escala/métodos , China
8.
Biophys J ; 121(6): 1081-1093, 2022 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-35122736

RESUMO

Protein glycation is a common, normally innocuous, post-translational modification in therapeutic monoclonal antibodies. However, when glycation occurs on complementarity-determining regions (CDRs) of a therapeutic monoclonal antibody, its biological activities (e.g., potency) may be impacted. Here, we present a comprehensive approach to understanding the mechanism of protein glycation using a bispecific antibody. Cation exchange chromatography and liquid chromatography-mass spectrometry were used to characterize glycation at a lysine residue within a heavy chain (HC) CDR (HC-CDR3-Lys98) of a bispecific antibody. Thermodynamic analysis revealed that this reaction is reversible and can occur under physiological conditions with an apparent affinity of 8-10 mM for a glucose binding to HC-CDR3-Lys98. Results from kinetic analysis demonstrated that this reaction follows Arrhenius behavior in the temperature range of 5°C-45°C and can be well predicted in vitro and in a non-human primate. In addition, this glycation reaction was found to be driven by an unusually low pKa on the ε-amino group of HC-CDR3-Lys98. Van't Hoff analysis and homology modeling suggested that this reaction is enthalpically driven, with this lysine residue surrounded by a microenvironment with low polarity. This study provides, to our knowledge, new insights toward a mechanistic understanding of protein glycation and strategies to mitigate the impact of protein glycation during pharmaceutical development.


Assuntos
Regiões Determinantes de Complementaridade , Lisina , Animais , Anticorpos Monoclonais/química , Cromatografia Líquida , Regiões Determinantes de Complementaridade/química , Regiões Determinantes de Complementaridade/metabolismo , Glicosilação , Cinética , Lisina/metabolismo
9.
J Biol Chem ; 298(3): 101619, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35065967

RESUMO

Celiac disease is a T cell-mediated chronic inflammatory condition often characterized by human leukocyte antigen (HLA)-DQ2.5 molecules presenting gluten epitopes derived from wheat, barley, and rye. Although some T cells exhibit cross-reactivity toward distinct gluten epitopes, the structural basis underpinning such cross-reactivity is unclear. Here, we investigated the T-cell receptor specificity and cross-reactivity of two immunodominant wheat gluten epitopes, DQ2.5-glia-α1a (PFPQPELPY) and DQ2.5-glia-ω1 (PFPQPEQPF). We show by surface plasmon resonance that a T-cell receptor alpha variable (TRAV) 4+-T-cell receptor beta variable (TRBV) 29-1+ TCR bound to HLA-DQ2.5-glia-α1a and HLA-DQ2.5-glia-ω1 with similar affinity, whereas a TRAV4- (TRAV9-2+) TCR recognized HLA-DQ2.5-glia-ω1 only. We further determined the crystal structures of the TRAV4+-TRBV29-1+ TCR bound to HLA-DQ2.5-glia-α1a and HLA-DQ2.5-glia-ω1, as well as the structure of an epitope-specific TRAV9-2+-TRBV7-3+ TCR-HLA-DQ2.5-glia-ω1 complex. We found that position 7 (p7) of the DQ2.5-glia-α1a and DQ2.5-glia-ω1 epitopes made very limited contacts with the TRAV4+ TCR, thereby explaining the TCR cross-reactivity across these two epitopes. In contrast, within the TRAV9-2+ TCR-HLA-DQ2.5-glia-ω1 ternary complex, the p7-Gln was situated in an electrostatic pocket formed by the hypervariable CDR3ß loop of the TCR and Arg70ß from HLA-DQ2.5, a polar network which would not be supported by the p7-Leu residue of DQ2.5-glia-α1a. In conclusion, we provide additional insights into the molecular determinants of TCR specificity and cross-reactivity to two closely-related epitopes in celiac disease.


Assuntos
Doença Celíaca , Glutens , Antígenos HLA-DQ , Linfócitos T CD4-Positivos/imunologia , Doença Celíaca/imunologia , Regiões Determinantes de Complementaridade/metabolismo , Reações Cruzadas/imunologia , Epitopos de Linfócito T/química , Epitopos de Linfócito T/imunologia , Glutens/imunologia , Antígenos HLA-DQ/química , Antígenos HLA-DQ/imunologia , Humanos , Epitopos Imunodominantes/metabolismo , Receptores de Antígenos de Linfócitos T/química , Receptores de Antígenos de Linfócitos T/imunologia , Especificidade do Receptor de Antígeno de Linfócitos T/imunologia
10.
Biochem Biophys Res Commun ; 585: 36-41, 2021 12 31.
Artigo em Inglês | MEDLINE | ID: mdl-34784549

RESUMO

One of the histopathological features of Alzheimer's disease (AD) is higher order neurofibrillary tangles formed by abnormally aggregated tau protein. The sequence 275VQIINK280 in the microtubule-binding domain of tau plays a key role in tau aggregation. Therefore, an aggregation inhibitor targeting the VQIINK region in tau may be an effective therapeutic agent for AD. We have previously shown that the Fab domain (Fab2r3) of a tau antibody that recognizes the VQIINK sequence can inhibit tau aggregation, and we have determined the tertiary structure of the Fab2r3-VQIINK complex. In this report, we determined the tertiary structure of apo Fab2r3 and analyzed differences in the structures of apo Fab2r3 and Fab2r3-VQIINK to examine the ligand recognition mechanism of Fab2r3. In comparison with the Fab2r3-VQIINK structure, there were large differences in the arrangement of the constant and variable domains in apo Fab2r3. Remarkable structural changes were especially observed in the H3 and L3 loop regions of the complementarity determining regions (CDRs) in apo Fab2r3 and the Fab2r3-VQIINK complex. These structural differences in CDRs suggest that formation of hydrophobic pockets suitable for the antigen is important for antigen recognition by tau antibodies.


Assuntos
Doença de Alzheimer/metabolismo , Motivos de Aminoácidos , Anticorpos Monoclonais/metabolismo , Agregados Proteicos , Agregação Patológica de Proteínas/metabolismo , Proteínas tau/metabolismo , Sequência de Aminoácidos , Anticorpos Monoclonais/química , Regiões Determinantes de Complementaridade/química , Regiões Determinantes de Complementaridade/metabolismo , Cristalografia por Raios X , Humanos , Fragmentos Fab das Imunoglobulinas/química , Fragmentos Fab das Imunoglobulinas/metabolismo , Modelos Moleculares , Emaranhados Neurofibrilares/química , Emaranhados Neurofibrilares/metabolismo , Ligação Proteica , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Proteínas tau/química , Proteínas tau/imunologia
11.
Int J Mol Sci ; 22(21)2021 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-34769474

RESUMO

The anti-La mab 312B, which was established by hybridoma technology from human-La transgenic mice after adoptive transfer of anti-human La T cells, immunoprecipitates both native eukaryotic human and murine La protein. Therefore, it represents a true anti-La autoantibody. During maturation, the anti-La mab 312B acquired somatic hypermutations (SHMs) which resulted in the replacement of four aa in the complementarity determining regions (CDR) and seven aa in the framework regions. The recombinant derivative of the anti-La mab 312B in which all the SHMs were corrected to the germline sequence failed to recognize the La antigen. We therefore wanted to learn which SHM(s) is (are) responsible for anti-La autoreactivity. Humanization of the 312B ab by grafting its CDR regions to a human Ig backbone confirms that the CDR sequences are mainly responsible for anti-La autoreactivity. Finally, we identified that a single amino acid replacement (D > Y) in the germline sequence of the CDR3 region of the heavy chain of the anti-La mab 312B is sufficient for anti-La autoreactivity.


Assuntos
Anticorpos Antinucleares/genética , Autoanticorpos/genética , Hipermutação Somática de Imunoglobulina/genética , Sequência de Aminoácidos , Aminoácidos/genética , Aminoácidos/metabolismo , Anticorpos Antinucleares/imunologia , Anticorpos Antinucleares/metabolismo , Autoanticorpos/química , Autoanticorpos/imunologia , Autoanticorpos/metabolismo , Autoimunidade/genética , Regiões Determinantes de Complementaridade/genética , Regiões Determinantes de Complementaridade/imunologia , Regiões Determinantes de Complementaridade/metabolismo , Epitopos/genética , Epitopos/imunologia , Células HeLa , Humanos , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/metabolismo , Análise de Sequência de Proteína
12.
Int Immunopharmacol ; 101(Pt A): 108292, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34710846

RESUMO

Leukopenia is a common manifestation of many diseases, including global outbreak SAS-CoV-2 infection. Granulocyte-macrophage colony-stimulating factor (GM -CSF) has been proved to be effective in promoting lymphocyte regeneration, but adverse immunological effects have also emerged. This study aim to investigate the effect of GM -CSF on BCR heavy chain CDR3 repertoire while promoting lymphocyte regeneration. Cyclophosphamide (CTX) and GM -CSF were used to inhibit and stimulate bone marrow hematopoiesis, respectively. High throughput sequencing was applied to detect the characteristics of BCR CDR3 repertoire in controls, CTX group and GM -CSF group. The white blood cells (WBCs) were quickly reduced (P < 0.05) with lymphocytes decreasing causing by CTX, and the WBCs and lymphocytes returned to the level of controls after GM -CSF treatment. The diversity of BCR heavy chain CDR3 repertoire was also significantly decreased in CTX group. Although there is still a big gap from the controls, the diversity was picked up after GM -CSF treatment. The expression of IGHD01-01, IGHD02-14 and IGHJ04-01 with high-frequency usage regularly and significantly changed in three groups, and many genes with low-frequency usage lost in CTX group and did not reappear in GM -CSF group. Moreover, two shared sequences and accounted for the highest proportion in GM -CSF group have been detected in animal model of chronic lymphocytic leukemia. These results revealed that GM -CSF can partially restore changes in the BCR heavy chain CDR3 repertoire while promoting lymphocyte regeneration, but it may also lead to rearrangement, proliferation and activation of abnormal B cells, which can provide a basis for further study on the adverse immunological effects and mechanism of GM -CSF treatment.


Assuntos
Ciclofosfamida/efeitos adversos , Fator Estimulador de Colônias de Granulócitos e Macrófagos/imunologia , Leucopenia/imunologia , Linfócitos/efeitos dos fármacos , Linfócitos/imunologia , Receptores de Antígenos de Linfócitos B/efeitos dos fármacos , Receptores de Antígenos de Linfócitos B/metabolismo , Animais , Regiões Determinantes de Complementaridade/efeitos dos fármacos , Regiões Determinantes de Complementaridade/genética , Regiões Determinantes de Complementaridade/metabolismo , Ciclofosfamida/uso terapêutico , Feminino , Fator Estimulador de Colônias de Granulócitos e Macrófagos/uso terapêutico , Cadeias Pesadas de Imunoglobulinas/efeitos dos fármacos , Cadeias Pesadas de Imunoglobulinas/genética , Cadeias Pesadas de Imunoglobulinas/metabolismo , Região de Junção de Imunoglobulinas/efeitos dos fármacos , Região de Junção de Imunoglobulinas/metabolismo , Região Variável de Imunoglobulina/efeitos dos fármacos , Região Variável de Imunoglobulina/metabolismo , Leucócitos/efeitos dos fármacos , Leucopenia/induzido quimicamente , Leucopenia/tratamento farmacológico , Linfócitos/metabolismo , Camundongos Endogâmicos BALB C , Receptores de Antígenos de Linfócitos B/imunologia
13.
Proc Natl Acad Sci U S A ; 118(39)2021 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-34551975

RESUMO

T cells play an important role in adaptive immunity. An enormous clonal diversity of T cells with a different specificity, encoded by the T cell receptor (TCR), protect the body against infection. Most TCRß chains are generated from a V, D, and J segment during recombination in the thymus. Although complete absence of the D segment is not easily detectable from sequencing data, we find convincing evidence for a substantial proportion of TCRß rearrangements lacking a D segment. Additionally, sequences without a D segment are more likely to be abundant within individuals and/or shared between individuals. Our analysis indicates that such sequences are preferentially generated during fetal development and persist within the elderly. Summarizing, TCRß rearrangements without a D segment are not uncommon, and tend to allow for TCRß chains with a high abundance in the naive repertoire.


Assuntos
Imunidade Adaptativa , Rearranjo Gênico da Cadeia beta dos Receptores de Antígenos dos Linfócitos T , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Linfócitos T/imunologia , Regiões Determinantes de Complementaridade/genética , Regiões Determinantes de Complementaridade/metabolismo , Glicina/deficiência , Humanos
14.
J Mol Biol ; 433(21): 167241, 2021 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-34508727

RESUMO

Autonomous heavy-chain variable (VH) domains are the smallest functional antibody fragments, and they possess unique features, including small size and convex paratopes, which provide enhanced targeting of concave epitopes that are difficult to access with larger conventional antibodies. However, human VH domains have evolved to fold and function with a light chain partner, and alone, they typically suffer from low stability and high aggregation propensity. Development of autonomous human VH domains, in which aggregation propensity is reduced without compromising antigen recognition, has proven challenging. Here, we used an autonomous human VH domain as a scaffold to construct phage-displayed synthetic libraries in which aspartate was systematically incorporated at different paratope positions. In selections, the library yielded many anti-EphA1 receptor VH domains, which were characterized in detail. Structural analyses of a parental anti-EphA1 VH domain and an improved variant provided insights into the effects of aspartate and other substitutions on preventing aggregation while retaining function. Our naïve libraries and in vitro selection procedures offer a systematic approach to generating highly functional autonomous human VH domains that resist aggregation and could be used for basic research and biomedical applications.


Assuntos
Ácido Aspártico/química , Sítios de Ligação de Anticorpos , Regiões Determinantes de Complementaridade/química , Cadeias Pesadas de Imunoglobulinas/química , Biblioteca de Peptídeos , Sequência de Aminoácidos , Ácido Aspártico/metabolismo , Sítios de Ligação , Clonagem Molecular , Regiões Determinantes de Complementaridade/genética , Regiões Determinantes de Complementaridade/metabolismo , Cristalografia por Raios X , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Humanos , Cadeias Pesadas de Imunoglobulinas/genética , Cadeias Pesadas de Imunoglobulinas/metabolismo , Cinética , Modelos Moleculares , Agregados Proteicos , Ligação Proteica , Conformação Proteica , Dobramento de Proteína , Domínios e Motivos de Interação entre Proteínas , Receptor EphA1/genética , Receptor EphA1/imunologia , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
15.
Chembiochem ; 22(20): 2957-2965, 2021 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-34411391

RESUMO

A nanobody is an antibody fragment consisting of a single monomeric variable antigen-binding domain. Mammalian cells are ideal platforms for identifying nanobodies targeting hard-to-display transmembrane proteins and nanobodies that function as modulators of cellular phenotypes. However, the introduction of a high-diversity nanobody library into mammalian cells is challenging. We have developed two novel methods for constructing a nanobody library in mammalian cells. Complementarity-determining region (CDR) random sequences were first incorporated into upstream and downstream dsDNAs by PCR. In the first method, named dsDNA-HR, upstream and downstream dsDNAs containing an identical overlapping sequence were co-transfected into cultured mammalian cells for intracellular homologous recombination that resulted in the formation of an intact nanobody library expression cassette. In the second method, named in vitro ligation, we generated full-length nanobody expression dsDNAs via ligation of restriction digested upstream and downstream dsDNAs. The obtained full-length dsDNAs were transfected into mammalian cells for nanobody library expression. Using both methods, we generated over a million unique nanobody sequences, as revealed by high-throughput sequencing. Single-cell sequencing was employed to resolve the diversity of the dsDNA-HR nanobody library. We also identified a small molecule, Nocodazole, which could enhance the efficacy of dsDNA-HR.


Assuntos
Regiões Determinantes de Complementaridade/química , DNA/química , Anticorpos de Domínio Único/química , Células Cultivadas , Regiões Determinantes de Complementaridade/genética , Regiões Determinantes de Complementaridade/metabolismo , DNA/genética , DNA/metabolismo , Células HEK293 , Humanos , Biblioteca de Peptídeos , Anticorpos de Domínio Único/metabolismo
16.
Nat Commun ; 12(1): 3815, 2021 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-34155209

RESUMO

Since the COVID-19 pandemic onset, the antibody response to SARS-CoV-2 has been extensively characterized. Antibodies to the receptor binding domain (RBD) on the spike protein are frequently encoded by IGHV3-53/3-66 with a short complementarity-determining region (CDR) H3. Germline-encoded sequence motifs in heavy chain CDRs H1 and H2 have a major function, but whether any common motifs are present in CDR H3, which is often critical for binding specificity, is not clear. Here, we identify two public clonotypes of IGHV3-53/3-66 RBD antibodies with a 9-residue CDR H3 that pair with different light chains. Distinct sequence motifs on CDR H3 are present in the two public clonotypes that seem to be related to differential light chain pairing. Additionally, we show that Y58F is a common somatic hypermutation that results in increased binding affinity of IGHV3-53/3-66 RBD antibodies with a short CDR H3. These results advance understanding of the antibody response to SARS-CoV-2.


Assuntos
Enzima de Conversão de Angiotensina 2/imunologia , Anticorpos Neutralizantes/imunologia , COVID-19/imunologia , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Sequência de Aminoácidos , Enzima de Conversão de Angiotensina 2/química , Enzima de Conversão de Angiotensina 2/metabolismo , Anticorpos Neutralizantes/química , Anticorpos Neutralizantes/metabolismo , Formação de Anticorpos , COVID-19/metabolismo , COVID-19/virologia , Regiões Determinantes de Complementaridade/química , Regiões Determinantes de Complementaridade/imunologia , Regiões Determinantes de Complementaridade/metabolismo , Cristalografia por Raios X , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Modelos Moleculares , Ligação Proteica , Domínios Proteicos , SARS-CoV-2/isolamento & purificação , SARS-CoV-2/metabolismo , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/metabolismo
17.
Sci Rep ; 11(1): 9971, 2021 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-33976265

RESUMO

Previously, we had cross-sectionally explored the characteristics of T cell receptor (TCR) repertoires from occupational medicamentosa-like dermatitis due to trichloroethylene (OMDT) patients, now we further analyzed the dynamic features of OMDT TCR repertoires. Peripheral blood TCR ß-chain complementarity-determining region 3 (CDR3) genes were detected with the high throughput sequencing in 24 OMDT cases in their acute, chronic and recovery stages, respectively, and in 24 trichloroethylene-exposed healthy controls. The TCR repertoire diversity, TRBV/TRBD/TRBJ gene usage and combination, frequencies of CDR3 nucleotide (nt) and amino acid (aa) sequences in the cases in different stages and in the controls were analyzed. TRBV6-4 and TRBV7-9 frequencies significantly differed between the cases and controls (both P < 6.1 × 10-4). TRBV6-4 combination with TRBJ2-1, TRBJ2-2, TRBJ2-3, and TRBJ2-6, and TRBV7-9 combination with TRBJ2-1 were associated with the stage by OMDT severity (all P < 0.001). Ten CDR3-nt and 7 CDR3-aa sequences in TRBV7-9-TRBJ2-1 combination and 1 CDR3-nt and 1 CDR3-aa sequences in TRBV6-4-TRBJ2-1 combination were identified as associated with the severity of OMDT (all P < 0.001). We revealed further how TCR repertoires vary with the severity in the development of OMDT, and severity-related TCRs may provide important therapeutic targets for OMDT in clinical practice.


Assuntos
Regiões Determinantes de Complementaridade/metabolismo , Dermatite/imunologia , Doenças Profissionais/induzido quimicamente , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Tricloroetileno/toxicidade , Adolescente , Adulto , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Doenças Profissionais/imunologia , Adulto Jovem
18.
Eur J Pharm Biopharm ; 165: 13-21, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33971271

RESUMO

We previously demonstrated that amorphous aggregates of misfolded VHH-7D12 antibodies (VHH-Mis), a potential anti-EGFR drug, can generate a robust serum IgG response. Here we investigate the immunogenic nature, especially the specificity of the immune response induced by VHH-Mis. To this end, we used two natively folded and 77% identical anti-EGFR VHHs (VHH-7D12 and VHH-9G8) that possess a common framework but distinct complementarity determining regions (CDRs). In 60% of mice immunized with VHH-Mis, the anti-VHH-7D12 IgG titer was stronger than the anti-VHH-9G8 titer (Group-1). In the remaining mice (40%; Group-2), the anti-VHH-7D12 and anti-VHH-9G8 titer were almost identical. We rationalized these results by hypothesizing that mice in Group-1 produced IgG mostly against the VHH-7D12's CDRs, whereas in Group-2 mice, they targeted the VHH's framework. The IgG specificity against VHH-7D12 and VHH-9G8 was essentially unchanged over 17 weeks in both groups. Further, in all mice (Group-1&2) re-immunized with native VHH-7D12, the IgG titer against VHH-7D12 increased sharply but not against VHH-9G8. On the other hand, none of the three Group-1 mice re-immunized with native VHH-9G8 showed immunogenicity against VHH-7D12 nor VHH-9G8. Whereas, in Group-2 mice (three/three) re-immunized with VHH-9G8, the IgG titers against both VHHs increased but slowly. Flow-cytometric studies showed that VHH-Mis immunized mice generated a higher number of effector and central memory T-cells. Overall, these observations indicate that amorphous aggregates made of a misfolded VHH can induce serum IgG against its natively folded self and analogous VHHs having a similar framework but distinct CDRs. Furthermore, a robust long-term immune response with memory was established against its natively folded self but with a nil-to-moderate immune response against natively folded VHH analogs.


Assuntos
Anticorpos Monoclonais/imunologia , Regiões Determinantes de Complementaridade/imunologia , Receptores ErbB/antagonistas & inibidores , Memória Imunológica , Agregados Proteicos/imunologia , Animais , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/química , Anticorpos Monoclonais/metabolismo , Regiões Determinantes de Complementaridade/administração & dosagem , Regiões Determinantes de Complementaridade/química , Regiões Determinantes de Complementaridade/metabolismo , Difusão Dinâmica da Luz , Feminino , Camundongos , Modelos Animais , Dobramento de Proteína , Fatores de Tempo
19.
J Cell Mol Med ; 25(8): 3991-4000, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33682267

RESUMO

Pancreatic cancer (PC) has been the fourth cancer-related death worldwide, diagnosed at an unresectable stage due to its rapid progression and few symptoms of this disease at early stages. The aim of this study was to determine the association between the diversity of T-cell receptor (TCR) repertoire and clinicopathological characteristics of patients with PC and other benign pancreatic diseases. In order to make a comprehensive analysis the TCR repertoire, high-throughput sequencing was used to differentiate complementarity determining region 3 (CDR3) of the TCR ß chain in peripheral blood samples from 3 PC, 3 chronic pancreatitis, 3 pancreatic cystic lesions and 3 pancreatic neuroendocrine tumour patients. We found that there were significant differences related to TCR repertoire between PC and other pancreatic diseases, and PC is a relatively immunosuppressive tumour. Changes of peripheral TCR repertoire may be used to predict the progression of PC and the response to immunotherapy. And there may exist novel-specific antigens in PC patients which could be used to design targeting immunotherapy in the nearly future.


Assuntos
Biomarcadores/metabolismo , Carcinoma Neuroendócrino/patologia , Regulação da Expressão Gênica , Cisto Pancreático/patologia , Neoplasias Pancreáticas/patologia , Pancreatite Crônica/patologia , Receptores de Antígenos de Linfócitos T/metabolismo , Adulto , Idoso , Carcinoma Neuroendócrino/sangue , Carcinoma Neuroendócrino/genética , Carcinoma Neuroendócrino/metabolismo , Regiões Determinantes de Complementaridade/genética , Regiões Determinantes de Complementaridade/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Cisto Pancreático/sangue , Cisto Pancreático/genética , Cisto Pancreático/metabolismo , Neoplasias Pancreáticas/sangue , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Pancreatite Crônica/sangue , Pancreatite Crônica/genética , Pancreatite Crônica/metabolismo , Prognóstico , Receptores de Antígenos de Linfócitos T/genética , Estudos Retrospectivos
20.
J Mol Biol ; 433(6): 166789, 2021 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-33387534

RESUMO

Centromeric loci of chromosomes are defined by nucleosomes containing the histone H3 variant CENP-A, which bind their DNA termini more permissively than their canonical counterpart, a feature that is critical for the mitotic fidelity. A recent cryo-EM study demonstrated that the DNA termini of CENP-A nucleosomes, reconstituted with the Widom 601 DNA sequence, are asymmetrically flexible, meaning one terminus is more clearly resolved than the other. However, an earlier work claimed that both ends could be resolved in the presence of two stabilizing single chain variable fragment (scFv) antibodies per nucleosome, and thus are likely permanently bound to the histone octamer. This suggests that the binding of scFv antibodies to the histone octamer surface would be associated with CENP-A nucleosome conformational changes, including stable binding of the DNA termini. Here, we present computational evidence that allows to explain at atomistic level the structural rearrangements of CENP-A nucleosomes resulting from the antibody binding. The antibodies, while they only bind the octamer façades, are capable of altering the dynamics of the nucleosomal core, and indirectly also the surrounding DNA. This effect has more drastic implications for the structure and the dynamics of the CENP-A nucleosome in comparison to its canonical counterpart. Furthermore, we find evidence that the antibodies bind the left and the right octamer façades at different affinities, another manifestation of the DNA sequence. We speculate that the cells could use induction of similar allosteric effects to control centromere function.


Assuntos
Proteína Centromérica A/química , DNA/ultraestrutura , Heterocromatina/ultraestrutura , Histonas/química , Nucleossomos/ultraestrutura , Sequência de Aminoácidos , Pareamento de Bases , Sítios de Ligação , Proteína Centromérica A/genética , Proteína Centromérica A/metabolismo , Regiões Determinantes de Complementaridade/química , Regiões Determinantes de Complementaridade/metabolismo , DNA/genética , DNA/metabolismo , Heterocromatina/genética , Heterocromatina/metabolismo , Histonas/genética , Histonas/metabolismo , Humanos , Modelos Moleculares , Simulação de Dinâmica Molecular , Conformação de Ácido Nucleico , Nucleossomos/genética , Nucleossomos/metabolismo , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Anticorpos de Cadeia Única/química , Anticorpos de Cadeia Única/metabolismo
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