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Park JY, Cho SH. Production of monoclonal antibody of heat-labile toxin A subunit to identify enterotoxigenic Escherichia coli by epitope mapping using synthetic peptides. Front Immunol 2023; 14:1152910. [PMID: 37275900 PMCID: PMC10232981 DOI: 10.3389/fimmu.2023.1152910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Accepted: 05/05/2023] [Indexed: 06/07/2023] Open
Abstract
Background Enterotoxigenic Escherichia coli (ETEC) is a major cause of diarrhea through two enterotoxins, a heat-labile toxin and a heat-stable toxin. These toxins alter the cellular signaling pathways, ultimately triggering an increase in chloride secretion and watery diarrhea. Objective For the development of an ETEC vaccine, we attempted to construct a peptide-specific monoclonal antibody library against heat-labile enterotoxin A subunit (LT-A) by epitope mapping using synthetic peptides. Methods Sera produced by five mice immunized with recombinant LT-A protein were examined for specific recognition with synthetic 15-mer and 34-mer peptides of LT-A proteins using enzyme-linked immunosorbent assay. The analysis revealed that the synthetic peptides number 8, 16, 24, 33, 36, 38, and 39 reacted with an anti-LT-A polyclonal antibody. For the possible prediction of LT-A epitopes, each full-length protein sequence was subjected to BCPreds analysis and three-dimensional protein structure analysis. The data showed that three peptides (synthetic peptide numbers: 33, 36, and 38-39) have identical antigenic specificities with LT-A protein, suggesting the usefulness of these linear peptide epitopes. Results Based on these peptides, we produced monoclonal antibodies to improve the specificity of LT-A detection. Monoclonal antibodies produced from two peptides (numbers 33 and 36) showed affinity for an LT-A recombinant antigen. Moreover, peptide epitope prediction analysis showed that the sites of the three peptides were identical to those exhibiting actual antigenicity. Also, it was confirmed that the amino acid sequence that actually showed antigenicity was included in the peptide predicted only by ETEC-LT-A-33. Also, the specificity of the antibody for ETEC-LT-A-33 was validated using bacterial cells, and the neutralizing effect of the antibody was determined by assessing cytokine release in infected HCT-8 cells. Conclusion The monoclonal antibodies produced in this study are useful toolsfor vaccine production against ETEC and can be used to identify peptide antigencandidates.
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Affiliation(s)
- Jun-Young Park
- Division of Zoonotic and Vector Borne Disease Research, Center for Infectious Disease Research, Korea National Institute of Health, Cheongju, Republic of Korea
- Environmental Diseases Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
| | - Seung-Hak Cho
- Division of Zoonotic and Vector Borne Disease Research, Center for Infectious Disease Research, Korea National Institute of Health, Cheongju, Republic of Korea
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Immunoinformatics and Pepscan strategies on the path of a peptide-based serological diagnosis of COVID19. J Immunol Methods 2021; 495:113071. [PMID: 33991531 PMCID: PMC8116314 DOI: 10.1016/j.jim.2021.113071] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 04/21/2021] [Accepted: 05/10/2021] [Indexed: 01/13/2023]
Abstract
Several diagnostic tools have been developed for clinical and epidemiological assays. RT-PCR and antigen detection tests are more useful for diagnosis of acute disease, while antibody tests allow the estimation of exposure in the population. Currently, there is an urgent need for the development of diagnostic tests for COVID-19 that can be used for large-scale epidemiological sampling. Through a comprehensive strategy, potential 16 mer antigenic peptides suited for antibody-based SARS-CoV-2 diagnosis were identified. A systematic scan of the three structural proteins (S,N and M) and the non-structural proteins (ORFs) present in the SARS-CoV-2 virus was conducted through the combination of immunoinformatic methods, peptide SPOT synthesis and an immunoassay with cellulose-bound peptides (Pepscan). The Pepscan filter paper sheets with synthetic peptides were tested against pools of sera of COVID-19 patients. Antibody recognition showed a strong signal for peptides corresponding to the S, N and M proteins of SARS-CoV-2 virus, but not for the ORFs proteins. The peptides exhibiting higher signal intensity were found in the C-terminal region of the N protein. Several peptides of this region showed strong recognition with all three immunoglobulins in the pools of sera. The differential reactivity observed between the different immunoglobulin isotypes (IgA, IgM and IgG) within different regions of the S and N proteins, can be advantageous for ensuring accurate diagnosis of all infected patients, with different times of exposure to infection. Few peptides of the M protein showed antibody recognition and no recognition was observed for peptides of the ORFs proteins.
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Petronijevic S, Stig S, Halstensen TS. Epitope mapping of anti-amelogenin IgG in untreated celiac children. Eur J Oral Sci 2021; 129:e12770. [PMID: 33656197 DOI: 10.1111/eos.12770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 01/04/2021] [Accepted: 01/12/2021] [Indexed: 11/28/2022]
Abstract
Children with untreated celiac disease (CeD) may develop enamel defects, and children with severe CeD have significantly increased levels of IgG to amelogenin, which may interfere with normal amelogenesis depending on which epitope(s) they bind. Children with untreated CeD (n = 42), for whom CeD had been confirmed either by biopsy (n = 17, cohort 1) or by the presence of particularly high serum levels of anti-transglutaminase 2 (TG2) IgA (n = 25, cohort 2), were selected from 146 children with CeD, and 10 controls were selected from 34 children who did not have CeD. Samples from these 52 children were used for detailed IgG anti-amelogenin, X isoform (AMELX) epitope mapping using 31 overlapping, 10-22mer peptides in ELISA. Although sera from both groups showed reactivity to peptides containing sequences from the N and C terminus of AMELX, sera from children with CeD reacted more strongly to peptides from the central region (amino acids 75-150) containing both a binding site for transforming growth factor-β (TGF-β), as well as the enzymatic cleavage sites for matrix metalloproteinase-20 and for kallikrein-4. Antigen-specific extraction revealed that only IgG to the central region cross-reacted to gliadin. Thus, cross-reactive anti-gliadin/amelogenin IgG may affect normal amelogenesis by interfering with enzymatic degradation, proper folding, and/or TGF-β signaling in children with untreated CeD.
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Affiliation(s)
- Sanja Petronijevic
- Institute of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
| | - Solveig Stig
- Institute of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway
| | - Trond S Halstensen
- Institute of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway.,Medical Department, Lovisenberg Diaconal Hospital, Oslo, Norway
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Prado IC, Chino META, Dos Santos AL, Souza ALA, Pinho LG, Lemos ERS, De-Simone SG. Development of an electrochemical immunosensor for the diagnostic testing of spotted fever using synthetic peptides. Biosens Bioelectron 2017; 100:115-121. [PMID: 28886455 DOI: 10.1016/j.bios.2017.08.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Revised: 07/29/2017] [Accepted: 08/12/2017] [Indexed: 01/11/2023]
Abstract
Spotted fever is a rare acute and multisystemic febrile infectious disease with a mortality rate of ≥50% without adequate antibiotic treatment, and in diagnosed and treated cases, of approximately 2.5%. Currently, the applied test to diagnose this disease is the indirect immunofluorescence reaction, however two samples of paired sera are necessary to confirm the diagnosis, since using only one sample may allow for confusion with cross reactions. OmpA is an outer membrane protein present in the R. rickettsia, the etiological agent of spotted fever, able to activate dendritic and macrophage cells. It also presents immunogenicity properties, and is considered a target for the development of diagnostic tests for spotted fever. In this context, an amperometric immunosensor was developed for the identification of sera antibodies (human IgG) from patients with spotted fever aimed at improving sensitivity and minimize sample volume. The development of the immunosensor was conducted using a synthetic peptide, derivative from the H6PGA4 R. rickettsia protein, homologous to OmpA. Amperometric responses were generated at -0.6 to 0.6V, at a scan rate of 0.025Vs-1 for 20 cycles, a limit of detection of approximately 10ngmL-1 for the synthetic peptides and 0.01µgmL-1 for the humam serum, a sensitivity of 2.59µA, adequate for the detection of spotted fever antibodies. The construction of this immunosensor, capable of identifying circulating antibodies in real time, can also be applied in the diagnosis of other infectious-parasitic diseases.
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Affiliation(s)
- Isis C Prado
- Center of Technological Development in Health (CDTS)/National Institute of Science and Technology for Innovation on Neglected Diseases (INCT-IDN), FIOCRUZ, Rio de Janeiro, RJ, Brazil.
| | - Mônica E T A Chino
- Laboratory of Experimental and Computational Biochemistry of Pharmaceuticals, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, RJ, Brazil
| | - Antonia L Dos Santos
- Laboratory of Experimental and Computational Biochemistry of Pharmaceuticals, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, RJ, Brazil
| | - André L A Souza
- Laboratory of Experimental and Computational Biochemistry of Pharmaceuticals, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, RJ, Brazil
| | - Luciano G Pinho
- Laboratory of Experimental and Computational Biochemistry of Pharmaceuticals, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, RJ, Brazil
| | - Elba R S Lemos
- Hantavirus and Rickettsia Laboratory, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, RJ, Brazil
| | - Salvatore G De-Simone
- Center of Technological Development in Health (CDTS)/National Institute of Science and Technology for Innovation on Neglected Diseases (INCT-IDN), FIOCRUZ, Rio de Janeiro, RJ, Brazil; Laboratory of Experimental and Computational Biochemistry of Pharmaceuticals, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, RJ, Brazil; Department of Cellular and Molecular Biology, Biology Institute, Federal University Fluminense, Niterói, RJ, Brazil
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Candreva ÁM, Ferrer-Navarro M, Bronsoms S, Quiroga A, Curciarello R, Cauerhff A, Petruccelli S, Docena GH, Trejo SA. Identification of cross-reactive B-cell epitopes between Bos d 9.0101(Bos Taurus) and Gly m 5.0101 (Glycine max) by epitope mapping MALDI-TOF MS. Proteomics 2017; 17:1700069. [PMID: 28643898 DOI: 10.1002/pmic.201700069] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 05/23/2017] [Accepted: 06/02/2017] [Indexed: 11/08/2022]
Abstract
Exposure to cow's milk constitutes one of the most common causes of food allergy. In addition, exposure to soy proteins has become relevant in a restricted proportion of milk allergic pediatric patients treated with soy formulae as a dairy substitute, because of the cross-allergenicity described between soy and milk proteins. We have previously identified several cross-reactive allergens between milk and soy that may explain this intolerance. The purpose of the present work was to identify epitopes in the purified αS1-casein and the recombinant soy allergen Gly m 5.0101 (Gly m 5) using an α-casein-specific monoclonal antibody (1D5 mAb) through two different approaches for epitope mapping, to understand cross-reactivity between milk and soy. The 1D5 mAb was immobilized onto magnetic beads, incubated with the peptide mixture previously obtained by enzymatic digestion of the allergens, and the captured peptides were identified by MALDI-TOF MS analysis. On a second approach, the peptide mixture was resolved by RP-HPLC and immunodominant peptides were identified by dot blot with the mAb. Finally, recognized peptides were sequenced by MALDI-TOF MS. This novel MS based approach led us to identify and characterize four peptides on α-casein and three peptides on Gly m 5 with a common core motif. Information obtained from these cross-reactive epitopes allows us to gain valuable insight into the molecular mechanisms of cross-reactivity, to further develop new and more effective vaccines for food allergy.
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Affiliation(s)
- Ángela María Candreva
- Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata (UNLP), La Plata, Argentina
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), CONICET, Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata (UNLP), La Plata, Argentina
| | - Mario Ferrer-Navarro
- Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona (UAB), Barcelona, Spain
| | - Silvia Bronsoms
- Servei de Proteomica i Biologia Estructural (SePBioEs), Universitat Autònoma de Barcelona (UAB), Barcelona, Spain
| | - Alejandra Quiroga
- Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata (UNLP), La Plata, Argentina
| | - Renata Curciarello
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), CONICET, Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata (UNLP), La Plata, Argentina
| | - Ana Cauerhff
- Laboratorio de Biología Molecular y Celular, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (UBA), CONICET, Buenos Aires, Argentina
| | - Silvana Petruccelli
- Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata (UNLP), La Plata, Argentina
| | - Guillermo Horacio Docena
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), CONICET, Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata (UNLP), La Plata, Argentina
| | - Sebastián Alejandro Trejo
- Servei de Proteomica i Biologia Estructural (SePBioEs), Universitat Autònoma de Barcelona (UAB), Barcelona, Spain
- Instituto Multidisciplinario de Biología Celular (IMBICE), CONICET, Comisión de Investigaciones Científicas de la Pcia. de Buenos Aires (CIC), Universidad Nacional de La Plata (UNLP), La Plata, Argentina
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Smith MH, Rodriguez EH, Weissman JS. Misfolded proteins induce aggregation of the lectin Yos9. J Biol Chem 2014; 289:25670-7. [PMID: 25086047 DOI: 10.1074/jbc.m114.583344] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A substantial fraction of nascent proteins delivered into the endoplasmic reticulum (ER) never reach their native conformations. Eukaryotes use a series of complementary pathways to efficiently recognize and dispose of these terminally misfolded proteins. In this process, collectively termed ER-associated degradation (ERAD), misfolded proteins are retrotranslocated to the cytosol, polyubiquitinated, and degraded by the proteasome. Although there has been great progress in identifying ERAD components, how these factors accurately identify substrates remains poorly understood. The targeting of misfolded glycoproteins in the ER lumen for ERAD requires the lectin Yos9, which recognizes the glycan species found on terminally misfolded proteins. In a role that remains poorly characterized, Yos9 also binds the protein component of ERAD substrates. Here, we identified a 45-kDa domain of Yos9, consisting of residues 22-421, that is proteolytically stable, highly structured, and able to fully support ERAD in vivo. In vitro binding studies show that Yos9(22-421) exhibits sequence-specific recognition of linear peptides from the ERAD substrate, carboxypeptidase Y G255R (CPY*), and binds a model unfolded peptide ΔEspP and protein Δ131Δ in solution. Binding of Yos9 to these substrates results in their cooperative aggregation. Although the physiological consequences of this substrate-induced aggregation remain to be seen, it has the potential to play a role in the regulation of ERAD.
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Affiliation(s)
- Melanie H Smith
- From the Department of Cellular and Molecular Pharmacology, Graduate Group in Biophysics, California Institute for Quantitative Biosciences, Center for RNA Systems Biology, and Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, California 94158
| | - Edwin H Rodriguez
- From the Department of Cellular and Molecular Pharmacology, Graduate Group in Biophysics, California Institute for Quantitative Biosciences, Center for RNA Systems Biology, and Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, California 94158
| | - Jonathan S Weissman
- From the Department of Cellular and Molecular Pharmacology, Graduate Group in Biophysics, California Institute for Quantitative Biosciences, Center for RNA Systems Biology, and Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, California 94158
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7
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Di Pisa M, Buccato P, Sabatino G, Real Fernández F, Berti B, Cocola F, Papini AM, Rovero P. Epitope mapping of the N-terminal portion of tissue transglutaminase protein antigen to identify linear epitopes in celiac disease. J Pept Sci 2014; 20:689-95. [PMID: 24831711 DOI: 10.1002/psc.2650] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 04/17/2014] [Accepted: 04/17/2014] [Indexed: 12/27/2022]
Abstract
Celiac disease (CD) is an autoimmune mediated disease with complex and multifactorial etiology. Gluten intake triggers a composite immune response involving T-cells and B-cells and leading to the secretion of autoantibodies if a genetic predisposition is present. Untreated CD patients show high levels of circulating autoantibodies directed to different auto-antigens present in the intestinal mucosa. The most important auto-antigen is the endomysial enzyme tissue transglutaminase (tTG). Both IgA and IgG antibody isotypes to tTG are known, but only the IgA antibodies demonstrate the highest disease specificity and thus are considered disease biomarkers. Because the pathogenicity and exact tTG binding properties of these autoantibodies are still unclear, the characterization of tTG antigenic domains is a crucial step in understanding CD onset and the autoimmune pathogenesis. Overlapping peptide libraries can be used for epitope mapping of selected protein portions to determine antigenic fragments contributing to the immunological activity and possibly develop innovative peptide-based tools with high specificity and sensitivity for CD. We performed an epitope mapping study to characterize putative linear auto-antigenic epitopes present in the tTG N-terminal portion (1-230). A library of 23 overlapping peptides spanning tTG(1-230) was generated by Fmoc/tBu solid-phase peptide synthesis and screened by immunoenzymatic assays employing patients' sera. The results indicate that four synthetic peptides, that is, Ac-tTG(1-15)-NH2 , Ac-tTG(41-55)-NH2 , Ac-tTG(51-65)-NH2 , and Ac-tTG(151-165)-NH2 , are recognized by IgA autoantibodies circulating in CD patients' sera. These results offer important insight on the nature of the antigen-antibody interaction.
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Affiliation(s)
- Margherita Di Pisa
- Laboratory of Peptide and Protein Chemistry and Biology, University of Florence, I-50019, Sesto Fiorentino, Italy; Department of Chemistry 'Ugo Schiff', University of Florence, I-50019, Sesto Fiorentino, Italy
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8
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Xiang Z, Tong W, Li Y, Qin C, Wei Q. Three unique Sendai virus antigenic peptides screened from nucleocapsid protein by overlapping peptide array. J Virol Methods 2013; 193:348-52. [PMID: 23811230 PMCID: PMC7113644 DOI: 10.1016/j.jviromet.2013.06.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 05/31/2013] [Accepted: 06/06/2013] [Indexed: 11/19/2022]
Abstract
Sendai virus (SeV) is strictly monitored in laboratory rodents. Currently, complete virions have been used as antigens in SeV serological tests. However, the complexity of SeV virion antigen limits the accuracy of the diagnostic method. In the current study, complete SeV virion antigen was separated on SDS-PAGE and analyzed, with nucleocapsid protein (NP) showing predominant antigenicity. A peptide array containing overlapping 14-mer peptides covering the entire NP was developed. The array used SeV positive serum and resulted in four antigenic linear peptides being identified, which were located in the carboxyl-terminus of NP. The four peptides were coated on ELISA plates and tested with SeV positive and SeV negative sera, and the antigenicity of three peptides, NP413-428, NP473-490 and NP507-524, was confirmed. Mixture of the three peptides showed comparable sensitivity and better specificity in clinical rat sera ELISA tests compared with complete SeV virion antigen. In conclusion, the three peptides, NP413-428, NP473-490 and NP507-524, would be good candidates as linear antigens for SeV detection.
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Affiliation(s)
- Zhiguang Xiang
- Institute of Laboratory Animal Science, Peking Union Medical College/Chinese Academy of Medical Science, Laboratory Animal Monitoring Center, Ministry of Health, Beijing 100021, China
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Kang M, Kim SY, An SSA, Ju YR. Characterizing affinity epitopes between prion protein and β-amyloid using an epitope mapping immunoassay. Exp Mol Med 2013; 45:e34. [PMID: 23907583 PMCID: PMC3789258 DOI: 10.1038/emm.2013.63] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Revised: 04/12/2013] [Accepted: 05/02/2013] [Indexed: 12/11/2022] Open
Abstract
Cellular prion protein, a membrane protein, is expressed in all mammals. Prion protein is also found in human blood as an anchorless protein, and this protein form is one of the many potential sources of misfolded prion protein replication during transmission. Many studies have suggested that β-amyloid1-42 oligomer causes neurotoxicity associated with Alzheimer's disease, which is mediated by the prion protein that acts as a receptor and regulates the hippocampal potentiation. The prevention of the binding of these proteins has been proposed as a possible preventative treatment for Alzheimer's disease; therefore, a greater understanding of the binding hot-spots between the two molecules is necessary. In this study, the epitope mapping immunoassay was employed to characterize binding epitopes within the prion protein and complementary epitopes in β-amyloid. Residues 23-39 and 93-119 in the prion protein were involved in binding to β-amyloid1-40 and 1-42, and monomers of this protein interacted with prion protein residues 93-113 and 123-166. Furthermore, β-amyloid antibodies against the C-terminus detected bound β-amyloid1-42 at residues 23-40, 104-122 and 159-175. β-Amyloid epitopes necessary for the interaction with prion protein were not determined. In conclusion, charged clusters and hydrophobic regions of the prion protein were involved in binding to β-amyloid1-40 and 1-42. The 3D structure appears to be necessary for β-amyloid to interact with prion protein. In the future, these binding sites may be utilized for 3D structure modeling, as well as for the pharmaceutical intervention of Alzheimer's disease.
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Affiliation(s)
- Mino Kang
- Department of Bionanotechnology, Gachon University, Gyeonggi, Korea
| | - Su Yeon Kim
- Division of Zoonoses, Center for Immunology and Pathology, National Institute of Health, Korea Centers for Disease Control and Prevention, Osong, Republic of Korea
| | - Seong Soo A An
- Department of Bionanotechnology, Gachon University, Gyeonggi, Korea
| | - Young Ran Ju
- Division of Zoonoses, Center for Immunology and Pathology, National Institute of Health, Korea Centers for Disease Control and Prevention, Osong, Republic of Korea
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Zhao G, Zhou A, Lv G, Meng M, Sun M, Bai Y, Han Y, Wang L, Zhou H, Cong H, Zhao Q, Zhu XQ, He S. Toxoplasma gondii cathepsin proteases are undeveloped prominent vaccine antigens against toxoplasmosis. BMC Infect Dis 2013; 13:207. [PMID: 23651838 PMCID: PMC3659040 DOI: 10.1186/1471-2334-13-207] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 05/01/2013] [Indexed: 12/31/2022] Open
Abstract
Background Toxoplasma gondii, an obligate intracellular apicomplexan parasite, infects a wide range of warm-blooded animals including humans. T. gondii expresses five members of the C1 family of cysteine proteases, including cathepsin B-like (TgCPB) and cathepsin L-like (TgCPL) proteins. TgCPB is involved in ROP protein maturation and parasite invasion, whereas TgCPL contributes to proteolytic maturation of proTgM2AP and proTgMIC3. TgCPL is also associated with the residual body in the parasitophorous vacuole after cell division has occurred. Both of these proteases are potential therapeutic targets in T. gondii. The aim of this study was to investigate TgCPB and TgCPL for their potential as DNA vaccines against T. gondii. Methods Using bioinformatics approaches, we analyzed TgCPB and TgCPL proteins and identified several linear-B cell epitopes and potential Th-cell epitopes in them. Based on these results, we assembled two single-gene constructs (TgCPB and TgCPL) and a multi-gene construct (pTgCPB/TgCPL) with which to immunize BALB/c mice and test their effectiveness as DNA vaccines. Results TgCPB and TgCPL vaccines elicited strong humoral and cellular immune responses in mice, both of which were Th-1 cell mediated. In addition, all of the vaccines protected the mice against infection with virulent T. gondii RH tachyzoites, with the multi-gene vaccine (pTgCPB/TgCPL) providing the highest level of protection. Conclusions T. gondii CPB and CPL proteases are strong candidates for development as novel DNA vaccines.
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Affiliation(s)
- Guanghui Zhao
- Department of Parasitology, Shandong University School of Medicine, Jinan, Shandong Province 250012, P R China.
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Abstract
The varied landscape of the adaptive immune response is determined by the peptides presented by immune cells, derived from viral or microbial pathogens or cancerous cells. The study of immune biomarkers or antigens is not new and classical methods such as agglutination, enzyme-linked immunosorbent assay, or Western blotting have been used for many years to study the immune response to vaccination or disease. However, in many of these traditional techniques, protein or peptide identification has often been the bottleneck. Recent advances in genomics and proteomics, has led to many of the rapid advances in proteomics approaches. Immunoproteomics describes a rapidly growing collection of approaches that have the common goal of identifying and measuring antigenic peptides or proteins. This includes gel based, array based, mass spectrometry, DNA based, or in silico approaches. Immunoproteomics is yielding an understanding of disease and disease progression, vaccine candidates, and biomarkers. This review gives an overview of immunoproteomics and closely related technologies that are used to define the full set of antigens targeted by the immune system during disease.
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Affiliation(s)
- Kelly M Fulton
- Human Health Therapeutics, National Research Council Canada, Ottawa, ON, Canada
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Falconar AKI. Epitope reactions can be gauged by relative antibody discriminating specificity (RADS) values supported by deletion, substitution and cysteine bridge formation analyses: potential uses in pathogenesis studies. BMC Res Notes 2012; 5:208. [PMID: 22546090 PMCID: PMC3392722 DOI: 10.1186/1756-0500-5-208] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Accepted: 04/30/2012] [Indexed: 01/05/2023] Open
Abstract
Background Epitope-mapping of infectious agents is essential for pathogenesis studies. Since polyclonal antibodies (PAbs) and monoclonal antibodies (MAbs) are always polyspecific and can react with multiple epitopes, it is important to distinguish between specific and non-specific reactions. Relative antibody discriminating specificity (RADS) values, obtained from their relative ELISA reactions with L-amino acid peptides prepared in the natural versus reverse orientations (x-fold absorbance natural/absorbance reverse = RADS value) may be valuable for this purpose. PAbs generated against the dengue type-2 virus (DENV-2) nonstructural-1 (NS1) glycoprotein candidate vaccine also reacted with both DENV envelope (E) glycoproteins and blood-clotting proteins. New xKGSx/xSGKx amino acid motifs were identified on DENV-2 glycoproteins, HIV-1 gp41 and factor IXa. Their potential roles in DENV and HIV-1 antibody-enhanced replication (AER) and auto-immunity were assessed. In this study, a) RADS values were determined for MAbs and PAbs, generated in congeneic (H2: class II) mice against DENV NS1 glycoprotein epitopes, to account for their cross-reaction patterns, and b) MAb 1G5.3 reactions with xKGSx/xSGKx motifs present in the DENV-4 NS1, E and HIV-1 glycoproteins and factor IXa were assessed after the introduction of amino acid substitutions, deletions, or intra-/inter-cysteine (C-C) bridges. Results MAbs 1H7.4, 5H4.3, 3D1.4 and 1G5.3 had high (4.23- to 16.83-fold) RADS values against single epitopes on the DENV-2 NS1 glycoprotein, and MAb 3D1.4 defined the DENV complex-conserved LX1 epitope. In contrast, MAbs 1G5.4-A1-C3 and 1C6.3 had low (0.47- to 1.67-fold) RADS values against multiple epitopes. PAb DENV complex-reactions occurred through moderately-high (2.77- and 3.11-fold) RADS values against the LX1 epitope. MAb 1G5.3 reacted with xSGKx motifs present in DENV-4 NS1 and E glycoproteins, HIV-1 gp41 and factor IXa, while natural C-C bridge formations or certain amino acid substitutions increased its binding activity. Conclusions These results: i) were readily obtained using a standard 96-well ELISA format, ii) showed the LX1 epitope to be the immuno-dominant DENV complex determinant in the NS1 glycoprotein, iii) supported an antigenic co-evolution of the DENV NS1 and E glycoproteins, and iv) identified methods that made it possible to determine the role of anti-DENV PAb reactions in viral pathogenesis.
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Affiliation(s)
- Andrew K I Falconar
- Laboratorio de Investigaciones en Enfermedades Tropicales, Departamento de Medicina, Universidad del Norte, Km5 Antigua via Puerto Colombia, Barranquilla, Colombia.
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O'Hara JM, Yermakova A, Mantis NJ. Immunity to ricin: fundamental insights into toxin-antibody interactions. Curr Top Microbiol Immunol 2012; 357:209-41. [PMID: 22113742 PMCID: PMC4433546 DOI: 10.1007/82_2011_193] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Ricin toxin is an extraordinarily potent inducer of cell death and inflammation. Ricin is also a potent provocateur of the humoral immune system, eliciting a mixture of neutralizing, non-neutralizing and even toxin-enhancing antibodies. The characterization of dozens of monoclonal antibodies (mAbs) against the toxin's enzymatic (RTA) and binding (RTB) subunits has begun to reveal fundamental insights into the underlying mechanisms by which antibodies neutralize (or fail to neutralize) ricin in systemic and mucosal compartments. This information has had immediate applications in the design, development and evaluation of ricin subunit vaccines and immunotherapeutics.
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Affiliation(s)
- Joanne M. O'Hara
- Division of Infectious Disease, Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, Albany, NY 12208, USA; Department of Biomedical Sciences, University at Albany School of Public Health, Albany, NY 12201, USA
| | - Anastasiya Yermakova
- Division of Infectious Disease, Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, Albany, NY 12208, USA; Department of Biomedical Sciences, University at Albany School of Public Health, Albany, NY 12201, USA
| | - Nicholas J. Mantis
- Division of Infectious Disease, Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, Albany, NY 12208, USA; Department of Biomedical Sciences, University at Albany School of Public Health, Albany, NY 12201, USA
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Zhao R, Cui S, Guo L, Wu C, Gonzalez R, Paranhos-Baccalà G, Vernet G, Wang J, Hung T. Identification of a highly conserved H1 subtype-specific epitope with diagnostic potential in the hemagglutinin protein of influenza A virus. PLoS One 2011; 6:e23374. [PMID: 21886787 PMCID: PMC3158760 DOI: 10.1371/journal.pone.0023374] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Accepted: 07/14/2011] [Indexed: 11/18/2022] Open
Abstract
Subtype specificity of influenza A virus (IAV) is determined by its two surface glycoproteins, hemagglutinin (HA) and neuraminidase (NA). For HA, 16 distinct subtypes (H1–H16) exist, while nine exist for NA. The epidemic strains of H1N1 IAV change frequently and cause annual seasonal epidemics as well as occasional pandemics, such as the notorious 1918 influenza pandemic. The recent introduction of pandemic A/H1N1 IAV (H1N1pdm virus) into humans re-emphasizes the public health concern about H1N1 IAV. Several studies have identified conserved epitopes within specific HA subtypes that can be used for diagnostics. However, immune specific epitopes in H1N1 IAV have not been completely assessed. In this study, linear epitopes on the H1N1pdm viral HA protein were identified by peptide scanning using libraries of overlapping peptides against convalescent sera from H1N1pdm patients. One epitope, P5 (aa 58–72) was found to be immunodominant in patients and to evoke high titer antibodies in mice. Multiple sequence alignments and in silico coverage analysis showed that this epitope is highly conserved in influenza H1 HA [with a coverage of 91.6% (9,860/10,767)] and almost completely absent in other subtypes [with a coverage of 3.3% (792/23,895)]. This previously unidentified linear epitope is located outside the five well-recognized antigenic sites in HA. A peptide ELISA method based on this epitope was developed and showed high correlation (χ2 = 51.81, P<0.01, Pearson correlation coefficient R = 0.741) with a hemagglutination inhibition test. The highly conserved H1 subtype-specific immunodominant epitope may form the basis for developing novel assays for sero-diagnosis and active surveillance against H1N1 IAVs.
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Affiliation(s)
- Rongmao Zhao
- State Key Laboratory of Molecular Virology and Genetic Engineering, and Christophe Mérieux Laboratory, Institute of Pathogen Biology, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Shujuan Cui
- State Key Laboratory of Molecular Virology and Genetic Engineering, and Christophe Mérieux Laboratory, Institute of Pathogen Biology, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Li Guo
- State Key Laboratory of Molecular Virology and Genetic Engineering, and Christophe Mérieux Laboratory, Institute of Pathogen Biology, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Chao Wu
- State Key Laboratory of Molecular Virology and Genetic Engineering, and Christophe Mérieux Laboratory, Institute of Pathogen Biology, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Richard Gonzalez
- State Key Laboratory of Molecular Virology and Genetic Engineering, and Christophe Mérieux Laboratory, Institute of Pathogen Biology, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
- Fondation Mérieux, Lyon, France
| | | | | | - Jianwei Wang
- State Key Laboratory of Molecular Virology and Genetic Engineering, and Christophe Mérieux Laboratory, Institute of Pathogen Biology, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
- * E-mail:
| | - Tao Hung
- State Key Laboratory of Molecular Virology and Genetic Engineering, and Christophe Mérieux Laboratory, Institute of Pathogen Biology, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
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Ivanenkov VV, Crawford PA, Toyama A, Sévigny J, Kirley TL. Epitope mapping in cell surface proteins by site-directed masking: defining the structural elements of NTPDase3 inhibition by a monoclonal antibody. Protein Eng Des Sel 2010; 23:579-88. [PMID: 20511214 DOI: 10.1093/protein/gzq027] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We adapted the method of epitope mapping by site-directed masking, which was described for purified soluble antigens [Paus,D. and Winter,G. (2006) Proc. Natl Acad. Sci. USA, 103, 9172-9177.], to map the binding site of an inhibitory monoclonal antibody on the cell surface protein ecto-nucleotidase NTPDase3. Using homology modeling, we built a 3D structure of NTPDase3 and designed 21 single cysteine mutations distributed over the surface of the enzyme. The mutant proteins were expressed in cells, biotinylated with a cysteine-specific reagent, and then extracted with detergent and immobilized on streptavidin-coated plates. Tethering NTPDase3 via cysteine residues located in a surface patch near the active site cleft masked the epitope and blocked antibody binding, as evaluated by enzyme inhibition assay and by ELISA. We then constructed 18 single alanine substitution mutations within the defined patch and found that W403A, D414A, E415A and R419A decreased the inhibitory effect of the antibody, whereas the double mutation W403A/R419A abolished both antibody binding and enzyme inhibition, suggesting the critical role of these residues for interaction with the antibody. Lack of competition between the antibody and a non-hydrolyzable substrate analog AMPPCP, as well as location of the epitope adjacent to the active site, suggest a noncompetitive mechanism of inhibition by steric hindrance. The described technique should be useful for systematic epitope mapping in cell membrane proteins for which either a 3D structure is available, or a sufficiently accurate 3D model can be obtained by homology modeling.
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Affiliation(s)
- Vasily V Ivanenkov
- Department of Pharmacology and Cell Biophysics, College of Medicine, University of Cincinnati, PO Box 670575, Cincinnati, OH 45267-0575, USA
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Benchmarking B-cell epitope prediction for the design of peptide-based vaccines: problems and prospects. J Biomed Biotechnol 2010; 2010:910524. [PMID: 20368996 PMCID: PMC2847767 DOI: 10.1155/2010/910524] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Revised: 12/12/2009] [Accepted: 02/18/2010] [Indexed: 11/18/2022] Open
Abstract
To better support the design of peptide-based vaccines, refinement of methods to predict B-cell epitopes necessitates meaningful benchmarking against empirical data on the cross-reactivity of polyclonal antipeptide antibodies with proteins, such that the positive data reflect functionally relevant cross-reactivity (which is consistent with antibody-mediated change in protein function) and the negative data reflect genuine absence of cross-reactivity (rather than apparent absence of cross-reactivity due to artifactual masking of B-cell epitopes in immunoassays). These data are heterogeneous in view of multiple factors that complicate B-cell epitope prediction, notably physicochemical factors that define key structural differences between immunizing peptides and their cognate proteins (e.g., unmatched electrical charges along the peptide-protein sequence alignments). If the data are partitioned with respect to these factors, iterative parallel benchmarking against the resulting subsets of data provides a basis for systematically identifying and addressing the limitations of methods for B-cell epitope prediction as applied to vaccine design.
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Chen Y, Pan Y, Guo Y, Qiu L, Ding X, Che X. Comprehensive mapping of immunodominant and conserved serotype- and group-specific B-cell epitopes of nonstructural protein 1 from dengue virus type 1. Virology 2010; 398:290-8. [PMID: 20079511 DOI: 10.1016/j.virol.2009.12.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Revised: 12/02/2009] [Accepted: 12/08/2009] [Indexed: 11/25/2022]
Abstract
The dengue virus (DENV) nonstructural protein 1 (NS1) is an immunogenic protein that holds potential for the development of vaccines and diagnostic reagents; however, the epitopes of NS1 have not been comprehensively mapped. We mapped B-cell linear epitopes on NS1 using 149 monoclonal antibodies with DENV serotype specificity and cross-reactivity as well as antisera from 27 mice immunized with the four DENV serotypes. Epitope recognition analysis was performed using a set of 15-mer sequential overlapping peptides that spanned the entire NS1 protein from DENV-1. This strategy identified three regions of NS1 that are DENV-1 serotype-specific epitopes, namely amino acid residues 1-15, 71-85, and 338-352. We also identified five group-specific B-cell epitopes that were highly conserved among isolates of the four DENV serotypes. These novel immunodominant serotype- and group-specific B-cell epitopes of DENV NS1 may aid the development of new dengue vaccines and diagnostic assays.
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Affiliation(s)
- Yue Chen
- Center for Clinical Laboratory, Zhujiang Hospital, Southern Medical University, No. 253 Gong ye da dao zhong, Guangzhou 510282, People's Republic of China
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Removal of B cell epitopes as a practical approach for reducing the immunogenicity of foreign protein-based therapeutics. Adv Drug Deliv Rev 2009; 61:977-85. [PMID: 19679153 DOI: 10.1016/j.addr.2009.07.014] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Revised: 07/09/2009] [Accepted: 07/14/2009] [Indexed: 11/23/2022]
Abstract
Immunogenicity of non-human proteins with useful therapeutic properties has prevented their development for use in the therapy of disease. However, this class of proteins could be very useful, if their immunogenicity could be markedly reduced so that many treatment cycles could be administered. One approach to reduce the immunogenicity of foreign proteins is to identify B cell epitopes on the protein and eliminate them by mutagenesis. In this article, theoretical aspects and experimental evidence for the feasibility of B cell epitope removal is reviewed. A special focus is given to our results with deimmunization of recombinant immunotoxins in which Fvs are fused to a 38kDa portion of the bacterial protein, Pseudomonas exotoxin A (PE38). Immunotoxins targeting CD22 and CD25 have produced complete remissions in many patients with drug resistant Hairy Cell Leukemia and are being evaluated in other malignancies. Experimental data summarized in this review indicates that removal of B cell epitopes is a practical approach for making less immunogenic protein therapeutics from non-human functional proteins. This approach requires grouping of the epitopes to identify targets for deimmunization followed by quantitative analysis of the decrease in affinity produced by the mutations in B cell epitopes.
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