scholarly journals Epitope Peptide-Based Predication and Other Functional Regions of Antigenic F and HN Proteins of Waterfowl and Poultry Avian Avulavirus Serotype-1 Isolates From Uganda

2021 ◽  
Vol 8 ◽  
Author(s):  
John Bosco Omony ◽  
Agnes Wanyana ◽  
Kizito K. Mugimba ◽  
Halid Kirunda ◽  
Jessica L. Nakavuma ◽  
...  
Keyword(s):  
Amino Acid ◽  
B Cell ◽  
Vaccine Strain ◽  
Cleavage Site ◽  
Wild Type ◽  
B Cell Epitopes ◽  
Antigenic Diversity ◽  
F Gene ◽  
Evolutionary Forces ◽  
Serotype 1

Uganda is a Newcastle disease (ND) endemic country where the disease is controlled by vaccination using live LaSota (genotype II) and I2 (genotype I) vaccine strains. Resurgent outbreak episodes call for an urgent need to understand the antigenic diversity of circulating wild Avian Avulavirus serotype-1 (AAvV-1) strains. High mutation rates and the continuous emergence of genetic and antigenic variants that evade immunity make non-segmented RNA viruses difficult to control. Antigenic and functional analysis of the key viral surface proteins is a crucial step in understanding the antigen diversity between vaccine lineages and the endemic wild ND viruses in Uganda and designing ND peptide vaccines. In this study, we used computational analysis, phylogenetic characterization, and structural modeling to detect evolutionary forces affecting the predicted immune-dominant fusion (F) and hemagglutinin-neuraminidase (HN) proteins of AAvV-1 isolates from waterfowl and poultry in Uganda compared with that in LaSota vaccine strain. Our findings indicate that mutational amino acid variations at the F protein in LaSota strain, 25 poultry wild-type and 30 waterfowl wild-type isolates were distributed at regions including the functional domains of B-cell epitopes or N-glycosylation sites, cleavage site, fusion site that account for strain variations. Similarly, conserved regions of HN protein in 25 Ugandan domestic fowl isolates and the representative vaccine strain varied at the flanking regions and potential linear B-cell epitope. The fusion sites, signal peptides, cleavage sites, transmembrane domains, potential B-cell epitopes, and other specific regions of the two protein types in vaccine and wild viruses varied considerably at structure by effective online epitope prediction programs. Cleavage site of the waterfowl isolates had a typical avirulent motif of 111GGRQGR'L117 with the exception of one isolate which showed a virulent motif of 111GGRQKR'F117. All the poultry isolates showed the 111GRRQKR'F117 motif corresponding to virulent strains. Amino acid sequence variations in both HN and F proteins of AAvV-1 isolates from poultry, waterfowl, and vaccine strain were distributed over the length of the proteins with no detectable pattern, but using the experimentally derived 3D structure data revealed key-mapped mutations on the surfaces of the predicted conformational epitopes encompassing the experimental major neutralizing epitopes. The phylogenic tree constructed using the full F gene and partial F gene sequences of the isolates from poultry and waterfowl respectively, showed that Ugandan ND aquatic bird and poultry isolates share some functional amino acids in F sequences yet do remain unique at structure and the B-cell epitopes. Recombination analyses showed that the C-terminus and the rest of the F gene in poultry isolates originated from prevalent velogenic strains. Altogether, these could provide rationale for antigenic diversity in wild ND isolates of Uganda compared with the current ND vaccine strains.

Prediction of linear B-cell epitopes using amino acid pair antigenicity scale

Amino Acids ◽  
2007 ◽  
Vol 33 (3) ◽  
pp. 423-428 ◽  
Author(s):  
J. Chen ◽  
H. Liu ◽  
J. Yang ◽  
K.-C. Chou
Keyword(s):  
Amino Acid ◽  
B Cell ◽  
Amino Acid Pair ◽  
B Cell Epitopes ◽  
Linear B

Using random forest to classify linear B-cell epitopes based on amino acid properties and molecular features

Biochimie ◽  
2014 ◽  
Vol 103 ◽  
pp. 1-6 ◽  
Author(s):  
Jian-Hua Huang ◽  
Ming Wen ◽  
Li-Juan Tang ◽  
Hua-Lin Xie ◽  
Liang Fu ◽  
...  
Keyword(s):  
Amino Acid ◽  
Random Forest ◽  
B Cell ◽  
B Cell Epitopes ◽  
Acid Properties ◽  
Molecular Features ◽  
Amino Acid Properties ◽  
Linear B

scholarly journals Characterization of Two Novel Linear B-Cell Epitopes in the Capsid Protein of Avian Hepatitis E Virus (HEV) That Are Common to Avian, Swine, and Human HEVs

2015 ◽  
Vol 89 (10) ◽  
pp. 5491-5501 ◽  
Author(s):  
Xinjie Wang ◽  
Qin Zhao ◽  
Lu Dang ◽  
Yani Sun ◽  
Jiming Gao ◽  
...  
Keyword(s):  
Amino Acid ◽  
B Cell ◽  
Capsid Protein ◽  
Hepatitis E Virus ◽  
Hepatitis E ◽  
Antigenic Structure ◽  
B Cell Epitopes ◽  
Avian Hepatitis E Virus ◽  
Avian Hev ◽  
Linear B

ABSTRACTAntisera raised against the avian hepatitis E virus (HEV) capsid protein are cross-reactive with human and swine HEV capsid proteins. In this study, two monoclonal antibodies (MAbs) against the avian HEV capsid protein, namely, 3E8 and 1B5, were shown to cross-react with the swine HEV capsid protein. The motifs involved in binding both MAbs were identified and characterized using phage display biopanning, peptide synthesis, and truncated or mutated protein expression, along with indirect enzyme-linked immunosorbent assay (ELISA) and Western blotting. The results showed that the I/VPHD motif is a necessary core sequence and that P and H are two key amino acids for recognition by MAb 3E8. The VKLYM/TS motif is the minimal amino acid sequence necessary for recognition by MAb 1B5. Cross-reactivity between the two epitopes and antibodies against avian, swine, and human HEVs in sera showed that both epitopes are common to avian, swine, and human HEVs. In addition, amino acid sequence alignment of the capsid proteins revealed that the key motifs of both novel epitopes are the same in HEVs from different animal species, predicting that they may be common to HEV isolates from boars, rabbits, rats, ferrets, mongooses, deer, and camels as well. Protein modeling analysis showed that both epitopes are at least partially exposed on the surface of the HEV capsid protein. Protective capacity analysis demonstrated that the two epitopes are nonprotective against avian HEV infection in chickens. Collectively, these studies characterize two novel linear B-cell epitopes common to avian, swine, and human HEVs, which furthers the understanding of HEV capsid protein antigenic structure.IMPORTANCEMore and more evidence indicates that the host range diversity of hepatitis E virus (HEV) is a global public health concern. A better understanding of the antigenic structure of the HEV capsid protein may improve disease diagnosis and prevention. In this study, binding site mapping and localization as well as the antigenic biology of two novel linear B-cell epitopes common to several different species of HEV were characterized. These findings partially reveal the antigenic structure of the HEV capsid protein and provide potential applications for the development of diagnostics and interventions for HEV infection.

scholarly journals Genetic Diversity of Plasmodium vivax Cysteine-Rich Protective Antigen (PvCyRPA) in Field Isolates from Five Different Areas of the Brazilian Amazon

Genes ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1657
Author(s):  
Lana Bitencourt Chaves ◽  
Glaucia de Oliveira Guimarães ◽  
Daiana de Souza Perce-da-Silva ◽  
Dalma Maria Banic ◽  
Paulo Renato Rivas Totino ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Amino Acid ◽  
B Cell ◽  
Plasmodium Vivax ◽  
Protective Antigen ◽  
Brazilian Amazon ◽  
Amino Acid Polymorphism ◽  
B Cell Epitopes ◽  
Field Isolates ◽  
Endemic Areas

The Plasmodium vivax Cysteine-Rich Protective Antigen (PvCyRPA) has an important role in erythrocyte invasion and has been considered a target for vivax malaria vaccine development. Nonetheless, its genetic diversity remains uncharted in Brazilian malaria-endemic areas. Therefore, we investigated the pvcyrpa genetic polymorphism in 98 field isolates from the Brazilian Amazon and its impact on the antigenicity of predicted B-cell epitopes. Genetic diversity parameters, population genetic analysis, neutrality test and the median-joining network were analyzed, and the potential amino acid polymorphism participation in B-cell epitopes was investigated. One synonymous and 26 non-synonymous substitutions defined fifty haplotypes. The nucleotide diversity and Tajima’s D values varied across the coding gene. The exon-1 sequence had greater diversity than those of exon-2. Concerning the prediction analysis, seven sequences were predicted as linear B cell epitopes, the majority contained in conformational epitopes. Moreover, important amino acid polymorphism was detected in regions predicted to contain residues participating in B-cell epitopes. Our data suggest that the pvcyrpa gene presents a moderate polymorphism in the studied isolates and such polymorphisms alter amino acid sequences contained in potential B cell epitopes, an important observation considering the antigen potentiality as a vaccine candidate to cover distinct P. vivax endemic areas worldwide.

scholarly journals Immunodominant linear B cell epitopes in the spike and membrane proteins of SARS-CoV-2 identified by immunoinformatics prediction and immunoassay

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kanokporn Polyiam ◽  
Waranyoo Phoolcharoen ◽  
Namphueng Butkhot ◽  
Chanya Srisaowakarn ◽  
Arunee Thitithanyanont ◽  
...  
Keyword(s):  
B Cell ◽  
Cleavage Site ◽  
Vaccine Development ◽  
Cell Epitope ◽  
Epitope Prediction ◽  
E Proteins ◽  
B Cell Epitopes ◽  
C Terminus ◽  
B Cell Epitope ◽  
Linear B

AbstractSARS-CoV-2 continues to infect an ever-expanding number of people, resulting in an increase in the number of deaths globally. With the emergence of new variants, there is a corresponding decrease in the currently available vaccine efficacy, highlighting the need for greater insights into the viral epitope profile for both vaccine design and assessment. In this study, three immunodominant linear B cell epitopes in the SARS-CoV-2 spike receptor-binding domain (RBD) were identified by immunoinformatics prediction, and confirmed by ELISA with sera from Macaca fascicularis vaccinated with a SARS-CoV-2 RBD subunit vaccine. Further immunoinformatics analyses of these three epitopes gave rise to a method of linear B cell epitope prediction and selection. B cell epitopes in the spike (S), membrane (M), and envelope (E) proteins were subsequently predicted and confirmed using convalescent sera from COVID-19 infected patients. Immunodominant epitopes were identified in three regions of the S2 domain, one region at the S1/S2 cleavage site and one region at the C-terminus of the M protein. Epitope mapping revealed that most of the amino acid changes found in variants of concern are located within B cell epitopes in the NTD, RBD, and S1/S2 cleavage site. This work provides insights into B cell epitopes of SARS-CoV-2 as well as immunoinformatics methods for B cell epitope prediction, which will improve and enhance SARS-CoV-2 vaccine development against emergent variants.

scholarly journals Conformational and Linear B-Cell Epitopes of Asp f 2, a Major Allergen of Aspergillus fumigatus, Bind Differently to Immunoglobulin E Antibody in the Sera of Allergic Bronchopulmonary Aspergillosis Patients

1999 ◽  
Vol 67 (5) ◽  
pp. 2284-2291 ◽  
Author(s):  
Banani Banerjee ◽  
Paul A. Greenberger ◽  
Jordan N. Fink ◽  
Viswanath P. Kurup
Keyword(s):  
Amino Acid ◽  
Aspergillus Fumigatus ◽  
B Cell ◽  
Immunoglobulin E ◽  
Allergic Bronchopulmonary Aspergillosis ◽  
Amino Acid Sequences ◽  
Epitope Region ◽  
B Cell Epitopes ◽  
Ige Binding ◽  
Binding Regions

ABSTRACT Asp f 2 is a major Aspergillus fumigatus allergen involved in allergic bronchopulmonary aspergillosis. Knowledge of the B-cell epitopes may contribute to the understanding of immunoregulation and immunodiagnosis. To elucidate the immunoglobulin E (IgE) binding epitopes in the linear sequence of Asp f 2, we synthesized decamer peptides spanning the whole molecule of Asp f 2 on derivatized cellulose membranes and evaluated IgE binding in ABPA patient and control sera. Peptides three to five amino acids long were synthesized based on amino acid sequences within the IgE binding regions and evaluated for the specificity of epitope antibody interactions. Nine IgE binding regions were recognized in this protein of 268 amino acid residues. Of the nine epitopes, seven (ATQRRQI, RKYFG, HWR, YTTRR, DHFAD, ALEAYA, and THEGGQ) are present in the hydrophilic regions of Asp f 2. Immunologic evaluation of the three recombinant fragments, Asp f 2A encompassing the N-terminal epitope region, Asp f 2B without N- and C-terminal regions of the protein, and Asp f 2C representing C-terminal epitopes, revealed that either the N- or C-terminal region of the protein is essential for the correct folding and conformation for IgE antibody binding.

B-Cell Epitopes Within The A2 and C2 Domains Of Coagulant Factor VIII Refined By Orthologous Protein Antigenicity

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1101-1101
Author(s):  
Philip M Zakas ◽  
Kristine Vanijcharoenkarn ◽  
Rebecca Markovitz ◽  
Shannon L. Meeks ◽  
Christopher B Doering
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
B Cell ◽  
Hemophilia A ◽  
Cross Reactivity ◽  
C2 Domain ◽  
B Cell Epitopes ◽  
C2 Domains ◽  
Group A ◽  
A2 Domain

Abstract Approximately 20-30% of severe hemophilia A patients develop inhibitors (anti-fVIII antibodies) to human fVIII (hfVIII) with the primary targets being the A2 and C2 domains. Studies of A2 domain-specific murine monoclonal antibodies (MAbs) targeting hfVIII identified 8 distinct groups of inhibitory MAbs displaying varying inhibitor titers and kinetics, with groups A, D, and E possessing the greatest inhibitory activity. Furthermore within the C2 domain, we previously characterized 5 distinct groups, whereby group BC antibodies were the most common and displayed the highest specific inhibitory activity. At present, a recombinant porcine fVIII (pfVIII) product (OBI-1, Baxter International) is being investigated within a pivotal clinical trial for persons with acquired hemophilia A. The rational for a recombinant pfVIII product stems from the limited cross reactivity of pfVIII, and potentially other fVIII orthologs, with antibodies developed against hfVIII and the prior clinical success of plasma-derived pfVIII. We have described the biochemical characterization of both pfVIII and, more recently, ovine fVIII (ofVIII) and now investigate their antigenic properties to define/refine key inhibitory epitopes and determine the amino acid differences that confer reduced antigenicity. Using an ELISA-based assay, 15 A2 and 12 C2 MAbs spanning all inhibitory groups were screened against B-domain deleted (BDD) pfVIII and ofVIII. Only 4 A2 domain targeting MAbs representing groups B, C, DE, and E were found to bind pfVIII and all displayed reduced cross-reactivity (Figure 1). Additionally, 3 MAbs within groups B, C, or E also bound ofVIII. No group A or D MAbs screened bound either ortholog. Of the C2 domain targeting MAbs tested, 3 MAbs (I109, D102, and ESH-8) from groups AB, B and C, respectively, bound pfVIII to lesser degrees. Nine of the 12 C2 targeting MAbs bound ofVIII, albeit at reduced signal strength, suggesting divergence in C2 epitopes between pfVIII and hfVIII as well as between pfVIII and ofVIII. Using these data and previous literature defining the specific epitopes of these MAbs, we suggest that species-specific amino acid sequence differences may be responsible for the differential binding. MAb413, a well characterized A2 group A inhibitor, was found not to bind either ortholog. Alanine scanning mutagenesis within the 484 – 508 epitope demonstrated that single point mutations at R484, Y487, R489, or P492 could each inhibit binding of MAb413 to below 10%. In addition, P485 or S488 mutations each reduced binding to approximately 40% (Lubin et al J Biol Chem 272:48). Both pfVIII and ofVIII share substitutions R484S, Y487H, R489G, and pfVIII contains unique substitutions P485A, S488P, and P492L. Since all but two A2 group A MAbs have been mapped to residues 484-508, and because all group A MAbs compete with each other for their epitope, we hypothesize that these substitutions are responsible for diminished binding of group A MAbs. Group D inhibitory antibodies have been mapped to residues 604-740. Within this region, there are 12 shared amino acid substitutions and 7 amino acids altered in either ortholog but not both. As it was demonstrated that the orthologs display differential cross reactivity, this suggests disparate amino acids alter inhibitor-epitope recognition. Walter et al. (J Biol Chem 2013 288:14) used small angle x-ray scattering (SAXS) to isolate the epitope of MAb 3E6, a C2 MAb group A inhibitor, to exposed loops R2209-S2216 and L2178-D2187. Our data show that this MAb is not cross reactive and both orthologs contain S2216T and S2182N substitutions. Finally, ESH-8, a well-studied C2 group C MAb, binds ofVIII and pfVIII equivalently at 29% of the hfVIII level. The epitope for ESH-8 contains amino acids 2248-2285 and within this region there is only one conserved substitution, F2275L. Therefore, we predict that substitution of this residue could restore or further diminish ESH-8 binding. These data provide evidence that the lack of A2 group A and D epitopes, as well as the C2 domain group BC epitopes within these orthologs may be responsible for the residual procoagulant activity in the context of inhibitor plasma. Furthermore, these data also suggest that 1) B-cell epitopes can be defined or refined through this approach, 2) less antigenic residues can be identified and 3) the information obtained can be utilized to rationally design recombinant fVIII products with reduced antigenicity. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Amino Acid Analysis of Fusion (F) Gene and Prediction of Epitope B-Cell Newcastle Disease Surabaya Isolate As Vaccine Candidate

2017 ◽  
Vol 3 (6) ◽  
pp. 316
Author(s):  
Indah Laili Rahmawati ◽  
Fedik Abdul Rantam ◽  
Wiwik Tyasningsih
Keyword(s):  
Amino Acid ◽  
B Cell ◽  
Newcastle Disease ◽  
Cleavage Site ◽  
Vaccine Candidate ◽  
Epitope Prediction ◽  
F Protein ◽  
Acid Cleavage ◽  
Embryonated Chicken ◽  
Online Software

The aims of this research is to determine pathotype according to composition amino acid cleavage site of F protein, and epitope prediction of F protein from Surabaya isolate. Samples were cloacal swabs of 28 backyard chickens from five wet markets in Surabaya, 9 ND positive isolates from Laboratory of Virology and Immunology Department Microbiology Airlangga University, and also positive LaSota isolates (ATCC). Samples were isolated on the embryonated chicken egg and identified by HA test. The viruses were confirmed as NDV by hemagglutination inhibition assay and RT-PCR with target 687 bp. Prediction of epitope were using online software IEDB. The result of epitope B cell prediction from each isolate showing 11-12 epitope B cell candidates in protein F. Thus, it could be concluded that ND virus which isolated from Surabaya has a chance as immunogen candidate, which can be developed as vaccine candidate. Key words: Newcastle disease, Cleavage site, Fusion protein, Surabaya

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