scholarly journals Disease‐Specific B Cell Epitopes for Serum Antibodies from Patients with Severe Acute Respiratory Syndrome (SARS) and Serologic Detection of SARS Antibodies by Epitope‐Based Peptide Antigens

2004 ◽  
Vol 190 (4) ◽  
pp. 797-809 ◽  
Author(s):  
I‐Ju Liu ◽  
Po‐Ren Hsueh ◽  
Chin‐Tarng Lin ◽  
Chien‐Yu Chiu ◽  
Chuan‐Liang Kao ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
B Cell ◽  
Serum Antibodies ◽  
B Cell Epitopes ◽  
Peptide Antigens ◽  
Disease Specific

scholarly journals MixedChlamydia trachomatisPeptide Antigens Provide a Specific and Sensitive Single-Well Colorimetric Enzyme-Linked Immunosorbent Assay for Detection of Human Anti-C. trachomatisAntibodies

mSphere ◽  
2018 ◽  
Vol 3 (6) ◽  
Author(s):  
K. Shamsur Rahman ◽  
Toni Darville ◽  
Harold C. Wiesenfeld ◽  
Sharon L. Hillier ◽  
Bernhard Kaltenboeck
Keyword(s):  
B Cell ◽  
High Specificity ◽  
Cross Reactivity ◽  
Specific Detection ◽  
B Cell Epitopes ◽  
Content Type ◽  
Peptide Antigens ◽  
Specificity And Sensitivity ◽  
Single Well ◽  
Individual Peptide

ABSTRACTSensitive and specific detection of anti-Chlamydia trachomatisantibodies in standard enzyme-linked immunosorbent assays (ELISAs) is compromised by cross-reactivity and poor sensitivity of classicalC.trachomatisantigens. Previously, we discovered 48 strongly reactive peptide antigens ofC. trachomatis-specific B-cell epitopes from 21 immunodominant proteins. By comprehensive individual testing of 11 top-ranked peptide antigens, we found very high sensitivity and specificity for detection of anti-C. trachomatisantibodies in chemiluminescent ELISAs. The current study established a labor-saving colorimetric ELISA by using a mixture of 12 strongly reactiveC. trachomatispeptide antigens (Ctr Mix1) in a single well/serum rather than assaying reactivity to each individual peptide. For performance evaluation, we used a simulated population of 212 anti-C. trachomatisantibody-positive and -negative sera from 125 women with NAAT-confirmed activeC. trachomatisinfection and from 87 healthy women at low risk forC. trachomatisinfection. In comparison to a composite reference standard (CRS) for anti-C. trachomatisantibody status, the Ctr Mix1 IgG ELISA achieved 93.9% sensitivity, significantly superior to the 49% to 79% sensitivities of four commercial anti-C. trachomatisIgG ELISAs, and 98% specificity of all tested assays. Compared to the labor-intensive individual peptide testing, this mixed peptide ELISA retained high specificity with only marginal, ∼5% sensitivity loss. By ROC-AUC, likelihood ratio, and predictive value analyses, the Ctr Mix1 ELISA performed satisfactorily at 10% to 75% prevalence range of anti-C. trachomatisantibodies but significantly better than commercial ELISAs. Thus, the labor-saving mixed peptide colorimetric ELISA format provides simultaneously high specificity and sensitivity for detection of anti-C. trachomatisantibodies.IMPORTANCEFor detection of anti-C. trachomatisantibodies by serological assays, use of classical chlamydial antigens results in high cross-reactivity and poor sensitivity. Previously, we discovered 48 strongly reactive peptide antigens ofC. trachomatis-specific B-cell epitopes from 21 immunodominant proteins, and individual testing and combined scoring of 5 to 11 peptide antigens provided highly sensitive and specific detection of anti-C. trachomatisantibodies in chemiluminescent ELISAs. To simplify this method, this study established a single-well labor-saving colorimetric ELISA using a mixture of 12 strongly reactiveC. trachomatispeptide antigens (Ctr Mix1) for detection of anti-C. trachomatisantibodies. This Ctr Mix1 ELISA (94% sensitivity and 98% specificity) outperformed 4 commercial ELISAs (49% to 79% sensitivity and 98% specificity). This ELISA can be easily implemented and commercialized, with convenient setup for use in nonspecialized laboratories. Thus, this mixed peptide assay with superior specificity and sensitivity will improve serodiagnosis ofC. trachomatisinfections.

scholarly journals Defining Species-Specific Immunodominant B Cell Epitopes for Molecular Serology of Chlamydia Species

2015 ◽  
Vol 22 (5) ◽  
pp. 539-552 ◽  
Author(s):  
K. Shamsur Rahman ◽  
Erfan U. Chowdhury ◽  
Anil Poudel ◽  
Anke Ruettger ◽  
Konrad Sachse ◽  
...  
Keyword(s):  
B Cell ◽  
Cell Epitope ◽  
Cross Reactivity ◽  
Microbial Pathogens ◽  
B Cell Epitopes ◽  
Content Type ◽  
Peptide Antigens ◽  
Sequence Identity ◽  
B Cell Epitope ◽  
Species Specific

ABSTRACTUrgently needed species-specific enzyme-linked immunosorbent assays (ELISAs) for the detection of antibodies againstChlamydiaspp. have been elusive due to high cross-reactivity of chlamydial antigens. To identifyChlamydiaspecies-specific B cell epitopes for such assays, we ranked the potential epitopes of immunodominant chlamydial proteins that are polymorphic among allChlamydiaspecies. High-scoring peptides were synthesized with N-terminal biotin, followed by a serine-glycine-serine-glycine spacer, immobilized onto streptavidin-coated microtiter plates, and tested with mono-specific mouse hyperimmune sera against eachChlamydiaspecies in chemiluminescent ELISAs. For each of nineChlamydiaspecies, three to nine dominant polymorphic B cell epitope regions were identified on OmpA, CT618, PmpD, IncA, CT529, CT442, IncG, Omp2, TarP, and IncE proteins. Peptides corresponding to 16- to 40-amino-acid species-specific sequences of these epitopes reacted highly and with absolute specificity with homologous, but not heterologous,Chlamydiamonospecies-specific sera. Host-independent reactivity of such epitopes was confirmed by testing of sixC. pecorum-specific peptides from five proteins withC. pecorum-reactive sera from cattle, the natural host ofC. pecorum. The probability of cross-reactivity of peptide antigens from closely related chlamydial species or strains correlated with percent sequence identity and declined to zero at <50% sequence identity. Thus, phylograms of B cell epitope regions predict the specificity of peptide antigens for rational use in the genus-, species-, or serovar-specific molecular serology ofChlamydiaspp. We anticipate that these peptide antigens will improve chlamydial serology by providing easily accessible assays to nonspecialist laboratories. Our approach also lends itself to the identification of relevant epitopes of other microbial pathogens.

scholarly journals The landscape of antibody binding in SARS-CoV-2 infection

2020 ◽  
Author(s):  
Anna S Heffron ◽  
Sean J McIlwain ◽  
Maya F Amjadi ◽  
David A Baker ◽  
Saniya Khullar ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Diagnostic Accuracy ◽  
B Cell ◽  
Immunosorbent Assay ◽  
Antibody Binding ◽  
Antibody Responses ◽  
Enzyme Linked Immunosorbent Assay ◽  
Peptide Microarray ◽  
B Cell Epitopes ◽  
Homologous Peptide

The search for potential antibody-based diagnostics, vaccines, and therapeutics for pandemic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has focused almost exclusively on the spike (S) and nucleocapsid (N) proteins. Coronavirus membrane (M), ORF3a, and ORF8 proteins are humoral immunogens in other coronaviruses (CoVs) but remain largely uninvestigated for SARS-CoV-2. Here we use ultradense peptide microarray mapping to show that SARS-CoV-2 infection induces robust antibody responses to epitopes throughout the SARS-CoV-2 proteome, particularly in M, in which one epitope achieved excellent diagnostic accuracy. We map 79 B cell epitopes throughout the SARS-CoV-2 proteome and demonstrate that antibodies that develop in response to SARS-CoV-2 infection bind homologous peptide sequences in the six other known human CoVs. We also confirm reactivity against four of our top-ranking epitopes by enzyme-linked immunosorbent assay (ELISA). Illness severity correlated with increased reactivity to nine SARS-CoV-2 epitopes in S, M, N, and ORF3a in our population. Our results demonstrate previously unknown, highly reactive B cell epitopes throughout the full proteome of SARS-CoV-2 and other CoV proteins.

scholarly journals Discovery of Human-Specific ImmunodominantChlamydia trachomatisB Cell Epitopes

mSphere ◽  
2018 ◽  
Vol 3 (4) ◽  
Author(s):  
K. Shamsur Rahman ◽  
Toni Darville ◽  
Ali N. Russell ◽  
Catherine M. O’Connell ◽  
Harold C. Wiesenfeld ◽  
...  
Keyword(s):  
B Cell ◽  
Cross Reactivity ◽  
Mouse Serum ◽  
Human Populations ◽  
Specific Detection ◽  
B Cell Epitopes ◽  
Content Type ◽  
Human Host ◽  
Peptide Antigens ◽  
Species Specific

ABSTRACTChlamydiaspecies-specific serology is compromised by cross-reactivity of the gold standard microimmunofluorescence (MIF) or commercial enzyme-linked immunosorbent assays (ELISAs). This study was conducted to discover novelC. trachomatis-specific peptide antigens that were recognized only by the antibody response of the natural human host. We evaluated a library of 271 peptide antigens from immunodominantC. trachomatisproteins by reactivity with 125C. trachomatisantibody-positive sera from women with PCR-confirmedC. trachomatisinfection and 17C. trachomatisantibody-negative sera from low-risk women never diagnosed withC. trachomatisinfection. TheseC. trachomatispeptide antigens had been predictedin silicoto contain B cell epitopes but had been nonreactive with mouse hyperimmune sera againstC. trachomatis. We discovered 38 novel human host-dependent antigens from 20 immunodominantC. trachomatisproteins (PmpD, IncE, IncG, CT529, CT618, CT442, TarP, CT143, CT813, CT795, CT223, PmpC, CT875, CT579, LcrE, IncA, CT226, CT694, Hsp60, and pGP3). Using these human sera, we also confirmed 10C. trachomatisB cell epitopes from 6 immunodominantC. trachomatisproteins (OmpA, PmpD, IncE, IncG, CT529, and CT618) as host species-independent epitopes that had been previously identified by their reactivity with mouse hyperimmune sera againstC. trachomatis. ELISA reactivities against these peptides correlated strongly with theC. trachomatismicroimmunofluorescence (MIF) text results (Pearson’s correlation coefficient [R] = 0.80;P< 10−6). TheseC. trachomatispeptide antigens do not cross-react with antibodies against otherChlamydiaspecies and are therefore suitable for species-specific detection of antibodies againstC. trachomatis. This study identified an extended set of peptide antigens for simpleC. trachomatis-specific ELISA serology.IMPORTANCECurrent serological assays for species-specific detection of anti-Chlamydiaspecies antibodies suffer from well-known shortcomings in specificity and ease of use. Due to the high prevalences of both anti-C. trachomatisand anti-C. pneumoniaeantibodies in human populations, species-specific serology is unreliable. Therefore, novel specific and simple assays for chlamydial serology are urgently needed. Conventional antigens are problematic due to extensive cross-reactivity withinChlamydiaspp. Using accurate B cell epitope prediction and a robust peptide ELISA methodology developed in our laboratory, we identified immunodominantC. trachomatisB cell epitopes by screening performed with sera fromC. trachomatis-infected women. We discovered 38 novel human host-dependent antigens from 20 immunodominantC. trachomatisproteins, in addition to confirming 10 host-independent mouse serum peptide antigens that had been identified previously. This extended set of highly specificC. trachomatispeptide antigens can be used in simple ELISA or multiplexed microarray formats and will provide high specificity and sensitivity to humanC. trachomatisserodiagnosis.

scholarly journals The landscape of antibody binding in SARS-CoV-2 infection

PLoS Biology ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. e3001265
Author(s):  
Anna S. Heffron ◽  
Sean J. McIlwain ◽  
Maya F. Amjadi ◽  
David A. Baker ◽  
Saniya Khullar ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Diagnostic Accuracy ◽  
B Cell ◽  
Immunosorbent Assay ◽  
Antibody Binding ◽  
Antibody Responses ◽  
Enzyme Linked Immunosorbent Assay ◽  
Peptide Microarray ◽  
B Cell Epitopes ◽  
Homologous Peptide

The search for potential antibody-based diagnostics, vaccines, and therapeutics for pandemic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has focused almost exclusively on the spike (S) and nucleocapsid (N) proteins. Coronavirus membrane (M), ORF3a, and ORF8 proteins are humoral immunogens in other coronaviruses (CoVs) but remain largely uninvestigated for SARS-CoV-2. Here, we use ultradense peptide microarray mapping to show that SARS-CoV-2 infection induces robust antibody responses to epitopes throughout the SARS-CoV-2 proteome, particularly in M, in which 1 epitope achieved excellent diagnostic accuracy. We map 79 B cell epitopes throughout the SARS-CoV-2 proteome and demonstrate that antibodies that develop in response to SARS-CoV-2 infection bind homologous peptide sequences in the 6 other known human CoVs. We also confirm reactivity against 4 of our top-ranking epitopes by enzyme-linked immunosorbent assay (ELISA). Illness severity correlated with increased reactivity to 9 SARS-CoV-2 epitopes in S, M, N, and ORF3a in our population. Our results demonstrate previously unknown, highly reactive B cell epitopes throughout the full proteome of SARS-CoV-2 and other CoV proteins.

scholarly journals Dynamic changes of acquired maternal SARS-CoV-2 IgG in infants

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xia Wang ◽  
Pu Yang ◽  
Junwen Zheng ◽  
Pin Liu ◽  
Cong Wei ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Pregnant Women ◽  
Dynamic Characteristics ◽  
Perinatal Infection ◽  
Serum Antibodies ◽  
Dynamic Changes ◽  
Transfer Rates ◽  
Positive Rate ◽  
Igg Level ◽  
Maternal Igg

AbstractAt present, there are still ambiguous reports about the perinatal infection of infants born to mothers infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The dynamic characteristics of infantile serum antibodies born to mother with SARS-CoV-2 has not been well described. In this study, we analyzed the seroconversion of 27 newborns born to 26 pregnant women infected with SARS-CoV-2. The SARS-CoV-2 IgG positive rate of parturient was 80.8%, and half of their infants obtained maternal IgG. IgG transfer rates were 18.8% and 81.8% in those infants whose mother infected less and more than 2 weeks before delivery. In the first two months of life, the IgG level of infants dropped sharply to one tenth of that at birth. These results suggest that maternal SARS-CoV-2 IgG provides limited protection for infants.

scholarly journals Linear B-Cell Epitopes in Human Norovirus GII.4 Capsid Protein Elicit Blockade Antibodies

Vaccines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 52
Author(s):  
Hassan Moeini ◽  
Suliman Qadir Afridi ◽  
Sainitin Donakonda ◽  
Percy A. Knolle ◽  
Ulrike Protzer ◽  
...  
Keyword(s):  
B Cell ◽  
Capsid Protein ◽  
Immune Escape ◽  
Solvent Accessibility ◽  
Effective Vaccine ◽  
Blood Group Antigens ◽  
Human Norovirus ◽  
B Cell Epitopes ◽  
Blocking Rate ◽  
Linear B

Human norovirus (HuNoV) is the leading cause of nonbacterial gastroenteritis worldwide with the GII.4 genotype accounting for over 80% of infections. The major capsid protein of GII.4 variants is evolving rapidly, resulting in new epidemic variants with altered antigenic potentials that must be considered for the development of an effective vaccine. In this study, we identify and characterize linear blockade B-cell epitopes in HuNoV GII.4. Five unique linear B-cell epitopes, namely P2A, P2B, P2C, P2D, and P2E, were predicted on the surface-exposed regions of the capsid protein. Evolving of the surface-exposed epitopes over time was found to correlate with the emergence of new GII.4 outbreak variants. Molecular dynamic simulation (MD) analysis and molecular docking revealed that amino acid substitutions in the putative epitopes P2B, P2C, and P2D could be associated with immune escape and the appearance of new GII.4 variants by affecting solvent accessibility and flexibility of the antigenic sites and histo-blood group antigens (HBAG) binding. Testing the synthetic peptides in wild-type mice, epitopes P2B (336–355), P2C (367–384), and P2D (390–400) were recognized as GII.4-specific linear blockade epitopes with the blocking rate of 68, 55 and 28%, respectively. Blocking rate was found to increase to 80% using the pooled serum of epitopes P2B and P2C. These data provide a strategy for expanding the broad blockade potential of vaccines for prevention of NoV infection.

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