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Search results for: epitope


#33453658   2021/01/13 To Up

Identification of nanobodies against hepatocellular carcinoma marker glypican-3.

Wenyi Wang, Chang Xu, Huanan Wang, Changan Jiang

1661 related Products with: Identification of nanobodies against hepatocellular carcinoma marker glypican-3.

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#33452891   2021/01/16 To Up

Identification and evaluation of novel vaccine candidates against Shigella flexneri through reverse vaccinology approach.

Shigellosis is a significant type of diarrhea that causes 160,000 deaths annually in a global scale. The mortality occurs mainly in children less than 5 years of age. No licensed vaccine is available, and conventional efforts for developing an effective and safe vaccine against shigellosis have not been succeeded yet. The reverse vaccinology is a novel promising method that screens genome or proteome of an organism for finding new vaccine candidates. In this study, through reverse vaccinology approach, new vaccine candidates against Shigella flexneri were identified and experimentally evaluated. Proteomes of S. flexneri were obtained from UniProt, and then outer membrane and extracellular proteins were predicted and selected for the evaluation of transmembrane domains, protein conservation, host homology, antigenicity, and solubility. From 103 proteins, 7 high-scored proteins were introduced as novel vaccine candidates, and after B- and T-cell epitope prediction, the best protein was selected for experimental studies. Recombinant protein was expressed, purified, and injected to BALB/c mice. The adhesion inhibitory effect of sera was also studied. The immunized mice demonstrated full protection against the lethal dose challenge. The sera remarkably inhibited S. flexneri adhesion to Caco-2 epithelial cells. The results indicate that identified antigen can serve for vaccine development against shigellosis and support reverse vaccinology for discovering novel effective antigens. KEY POINTS: • Seven Shigella new antigens were identified by reverse vaccinology (RV) approach. • The best antigen experimented demonstrated full protection against lethal dose. • In vivo results verified RV analyses and suggest FimG as a new potent vaccine candidate.
Abolfazl Hajialibeigi, Jafar Amani, Seyed Latif Mousavi Gargari

1092 related Products with: Identification and evaluation of novel vaccine candidates against Shigella flexneri through reverse vaccinology approach.

200 1 mL2.5 mg100ug100 µg10 mg4 x 10,000 Units 5 G1 mL1,000 tests100ul

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#33452310   2021/01/15 To Up

Modified recombinant human erythropoietin with potentially reduced immunogenicity.

Recombinant human erythropoietin (rHuEPO) is a biopharmaceutical drug given to patients who have a low hemoglobin related to chronic kidney disease, cancer or anemia. However, some patients repeatedly receiving rHuEPO develop anti-rHuEPO neutralizing antibodies leading to the development of pure red cell aplasia (PRCA). The immunogenic antibody response activated by rHuEPO is believed to be triggered by T-cells recognizing EPO epitopes bound to MHC molecules displayed on the cell surface of APCs. Previous studies have reported an association between the development of anti-rHuEpo-associated PRCA and the HLA-DRB1*09 gene, which is reported to be entrenched in the Thai population. In this study, we used computational design to screen for immunogenic hotspots recognized by HLA-DRB1*09, and predicted seventeen mutants having anywhere between one through four mutations that reduce affinity for the allele, without disrupting the structural integrity and bioactivity. Five out of seventeen mutants were less immunogenic in vitro while retaining similar or slightly reduced bioactivity than rHuEPO. These engineered proteins could be the potential candidates to treat patients who are rHuEpo-dependent and express the HLA-DRB1*09 allele.
Thanutsorn Susantad, Mayuree Fuangthong, Kannan Tharakaraman, Phanthakarn Tit-Oon, Mathuros Ruchirawat, Ram Sasisekharan

2239 related Products with: Modified recombinant human erythropoietin with potentially reduced immunogenicity.

1 mg50 μg50050 μg20 μg25220 μg201 mg220

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#33451552   2020/08/13 To Up

Citrullinome of Porphyromonas gingivalis Outer Membrane Vesicles: Confident Identification of Citrullinated Peptides.

Porphyromonas gingivalis is a key pathogen in chronic periodontitis and has recently been mechanistically linked to the development of rheumatoid arthritis via the activity of peptidyl arginine deiminase generating citrullinated epitopes in the periodontium. In this project the outer membrane vesicles (OMV) from P. gingivalis W83 wild-type (WT), a W83 knock-out mutant of peptidyl arginine deiminase (ΔPPAD), and a mutant strain expressing PPAD with the active site cysteine mutated to alanine (C351A), have been analyzed using a two-dimensional HFBA-based separation system combined with LC-MS. For optimal and positive identification and validation of citrullinated peptides and proteins, high resolution mass spectrometers and strict MS search criteria were utilized. This may have compromised the total number of identified citrullinations but increased the confidence of the validation. A new two-dimensional separation system proved to increase the strength of validation, and along with the use of an in-house build program, Citrullia, we establish a fast and easy semi-automatic (manual) validation of citrullinated peptides. For the WT OMV we identified 78 citrullinated proteins having a total of 161 citrullination sites. Notably, in keeping with the mechanism of OMV formation, the majority (51 out of 78) of citrullinated proteins were predicted to be exported via the inner membrane and to reside in the periplasm or being translocated to the bacterial surface. Citrullinated surface proteins may contribute to the pathogenesis of rheumatoid arthritis. For the C351A-OMV a single citrullination site was found and no citrullinations were identified for the ΔPPAD-OMV, thus validating the unbiased character of our method of citrullinated peptide identification.
Daniel Nyberg Larsen, Christian Engelbrecht Mikkelsen, Mads Kierkegaard, Grzegorz P Bereta, Zuzanna Nowakowska, Jakub Z Kaczmarek, Jan Potempa, Peter Højrup

1850 related Products with: Citrullinome of Porphyromonas gingivalis Outer Membrane Vesicles: Confident Identification of Citrullinated Peptides.

0.1 ml 5 G96T100ug1 mL4 Membranes/Box1 kit0,8 6 ml Ready-to-use 100ul200 ug

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#33451551   2020/08/13 To Up

Functional Characterization and Comparison of Plasmodium falciparum Proteins as Targets of Transmission-blocking Antibodies.

Plasmodium falciparum malaria continues to evade control efforts, utilizing highly specialized sexual-stages to transmit infection between the human host and mosquito vector. In a vaccination model, antibodies directed to sexual-stage antigens, when ingested in the mosquito blood meal, can inhibit parasite growth in the midgut and consequently arrest transmission. Despite multiple datasets for the Plasmodium sexual-stage transcriptome and proteome, there have been no rational screens to identify candidate antigens for transmission-blocking vaccine (TBV) development. This study characterizes 12 proteins from across the P. falciparum sexual-stages as possible TBV targets. Recombinant proteins are heterologously expressed as full-length ectodomains in a mammalian HEK293 cell system. The proteins recapitulate native parasite epitopes as assessed by indirect fluorescence assay and a proportion exhibits immunoreactivity when tested against sera from individuals living in malaria-endemic Burkina Faso and Mali. Purified IgG generated to the mosquito-stage parasite antigen enolase demonstrates moderate inhibition of parasite development in the mosquito midgut by the ex vivo standard membrane feeding assay. The findings support the use of rational screens and comparative functional assessments in identifying proteins of the P. falciparum transmission pathway and establishing a robust pre-clinical TBV pipeline.
Daria Nikolaeva, Joseph J Illingworth, Kazutoyo Miura, Daniel G W Alanine, Iona J Brian, Yuanyuan Li, Alex J Fyfe, Dari F Da, Anna Cohuet, Carole A Long, Simon J Draper, Sumi Biswas

2305 related Products with: Functional Characterization and Comparison of Plasmodium falciparum Proteins as Targets of Transmission-blocking Antibodies.

1 mg1mg1mg105 μg1mg1mg1mg100ul510mg100

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#33451411   2020/11/23 To Up

Immunopeptidomic Analysis Reveals That Deamidated HLA-bound Peptides Arise Predominantly from Deglycosylated Precursors.

The presentation of post-translationally modified (PTM) peptides by cell surface HLA molecules has the potential to increase the diversity of targets for surveilling T cells. Although immunopeptidomics studies routinely identify thousands of HLA-bound peptides from cell lines and tissue samples, in-depth analyses of the proportion and nature of peptides bearing one or more PTMs remains challenging. Here we have analyzed HLA-bound peptides from a variety of allotypes and assessed the distribution of mass spectrometry-detected PTMs, finding deamidation of asparagine or glutamine to be highly prevalent. Given that asparagine deamidation may arise either spontaneously or through enzymatic reaction, we assessed allele-specific and global motifs flanking the modified residues. Notably, we found that the N-linked glycosylation motif NX(S/T) was highly abundant across asparagine-deamidated HLA-bound peptides. This finding, demonstrated previously for a handful of deamidated T cell epitopes, implicates a more global role for the retrograde transport of nascently N-glycosylated polypeptides from the ER and their subsequent degradation within the cytosol to form HLA-ligand precursors. Chemical inhibition of Peptide:N-Glycanase (PNGase), the endoglycosidase responsible for the removal of glycans from misfolded and retrotranslocated glycoproteins, greatly reduced presentation of this subset of deamidated HLA-bound peptides. Importantly, there was no impact of PNGase inhibition on peptides not containing a consensus NX(S/T) motif. This indicates that a large proportion of HLA-I bound asparagine deamidated peptides are generated from formerly glycosylated proteins that have undergone deglycosylation via the ER-associated protein degradation (ERAD) pathway. The information herein will help train deamidation prediction models for HLA-peptide repertoires and aid in the design of novel T cell therapeutic targets derived from glycoprotein antigens.
Shutao Mei, Rochelle Ayala, Sri H Ramarathinam, Patricia T Illing, Pouya Faridi, Jiangning Song, Anthony W Purcell, Nathan P Croft

2149 related Products with: Immunopeptidomic Analysis Reveals That Deamidated HLA-bound Peptides Arise Predominantly from Deglycosylated Precursors.

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#33450807   2021/01/13 To Up

Ligand-Receptor Interaction: AMA-1 Contains Small Regions Governing Bovine Erythrocyte Binding.

Apical membrane antigen 1 is a microneme protein which plays an indispensable role during Apicomplexa parasite invasion. The detailed mechanism of AMA-1 molecular interaction with its receptor on bovine erythrocytes has not been completely defined in . This study was focused on identifying the minimum AMA-1-derived regions governing specific and high-affinity binding to its target cells. Different approaches were used for detecting locus genetic variability and natural selection signatures. The binding properties of twelve highly conserved 20-residue-long peptides were evaluated using a sensitive and specific binding assay based on radio-iodination. AMA-1 ectodomain structure was modelled and refined using molecular modelling software. NetMHCIIpan software was used for calculating B- and T-cell epitopes. The gene had regions under functional constraint, having the highest negative selective pressure intensity in the Domain I encoding region. Interestingly, AMA-1-DI (YMQKFDIPRNHGSGIYVDLG and GYESVGSKSYRMPVGKCPVV) and DII (CPMHPVRDAIFGKWSGGSCV)-derived peptides had high specificity interaction with erythrocytes and bound to a chymotrypsin and neuraminidase-treatment sensitive receptor. DI-derived peptides appear to be exposed on the protein's surface and contain predicted B- and T-cell epitopes. These findings provide data (for the first-time) concerning AMA-1 functional subunits which are important for establishing receptor-ligand interactions which could be used in synthetic vaccine development.
Laura Cuy-Chaparro, Michel David Bohórquez, Gabriela Arévalo-Pinzón, Jeimmy Johana Castañeda-Ramírez, Carlos Fernando Suárez, Laura Pabón, Diego Ordóñez, Gina Marcela Gallego-López, Carlos Esteban Suárez, Darwin Andrés Moreno-Pérez, Manuel Alfonso Patarroyo

2520 related Products with: Ligand-Receptor Interaction: AMA-1 Contains Small Regions Governing Bovine Erythrocyte Binding.

100 UG100ug Lyophilized100ug100ug Lyophilized100ug Lyophilized100ug100ug100ug10 ml100ug100ug100ug Lyophilized

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#33450518   2021/01/12 To Up

Dendritic cells focus CTL responses toward highly conserved and topologically important HIV-1 epitopes.

During early HIV-1 infection, immunodominant T cell responses to highly variable epitopes lead to the establishment of immune escape virus variants. Here we assessed a type 1-polarized monocyte-derived dendritic cell (MDC1)-based approach to selectively elicit cytotoxic T lymphocyte (CTL) responses against highly conserved and topologically important HIV-1 epitopes in HIV-1-infected individuals from the Thailand RV254/SEARCH 010 cohort who initiated antiretroviral therapy (ART) during early infection (Fiebig stages I-IV).
Tatiana M Garcia-Bates, Mariana L Palma, Renee R Anderko, Denise C Hsu, Jintanat Ananworanich, Bette T Korber, Gaurav D Gaiha, Nittaya Phanuphak, Rasmi Thomas, Sodsai Tovanabutra, Bruce D Walker, John W Mellors, Paolo A Piazza, Eugene Kroon, Sharon A Riddler, Nelson L Michael, Charles R Rinaldo, Robbie B Mailliard,

1049 related Products with: Dendritic cells focus CTL responses toward highly conserved and topologically important HIV-1 epitopes.

100ul1000 tests100ml100ul100ml25 1x10e7 cells100ml1000 pieces/case200 100ìl x 10 vials

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#33450502   2020/12/29 To Up

Identification and evaluation of immunogenic MHC-I and MHC-II binding peptides from Mycobacterium tuberculosis.

Due to several limitations of the only available BCG vaccine, to generate adequate protective immune responses, it is important to develop potent and cost-effective vaccines against tuberculosis (TB). In this study, we have used an immune-informatics approach to identify potential peptide based vaccine targets against TB. The proteome of Mycobacterium tuberculosis (Mtb), the causative agent of TB, was analyzed for secretory or surface localized antigenic proteins as potential vaccine candidates. The T- and B-cell epitopes as well as MHC molecule binding efficiency were identified and mapped in the modelled structures of the selected proteins. Based on antigenicity score and molecular dynamic simulation (MD) studies two peptides namely Pep-9 and Pep-15 were analyzed, modelled and docked with MHC-I and MHC-II structures. Both peptides exhibited no cytotoxicity and were able to induce proinflammatory cytokine secretion in stimulated macrophages. The molecular docking, MD and in-vitro studies of the predicted B and T-cell epitopes of Pep-9 and Pep-15 peptides with the modelled MHC structures exhibited strong binding affinity and antigenic properties, suggesting that the complex is stable, and that these peptides can be considered as a potential candidates for the development of vaccine against TB.
Manaswini Jagadeb, Kali Prasad Pattanaik, Surya Narayan Rath, Avinash Sonawane

1824 related Products with: Identification and evaluation of immunogenic MHC-I and MHC-II binding peptides from Mycobacterium tuberculosis.

1000 TESTS/0.65ml0.025 mg100 mg200ul100ug Lyophilized10 mg100.00 ug0.1 mg 25 MG200ug100 Tests100ug Lyophilized

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#33450322   2021/01/12 To Up

The impact of size on particle drainage dynamics and antibody response.

Vaccine-induced immune response can be greatly enhanced by mimicking pathogen properties. The size and the repetitive geometric shape of virus-like particles (VLPs) influence their immunogenicity by facilitating drainage to secondary lymphoid organs and enhancing interaction with and activation of B cells and innate humoral immune components. VLPs derived from the plant Bromovirus genus, specifically cowpea chlorotic mottle virus (CCMV), are T = 3 icosahedral particles. (T) is the triangulation number that refers to the number and arrangements of the subunits (pentamers and hexamers) of the VLPs. CCMV-VLPs can be easily expressed in an E. coli host system and package ssRNA during the expression process. Recently, we have engineered CCMV-VLPs by incorporating the universal tetanus toxoid (TT) epitope at the N-terminus. The modified CCMV-VLPs successfully form icosahedral particles T = 3, with a diameter of ~30 nm analogous to the parental VLPs. Interestingly, incorporating TT epitope at the C-terminus of CCMV-VLPs results in the formation of Rod-shaped VLPs, ~1 μm in length and ~ 30 nm in width. In this study, we have investigated the draining kinetics and immunogenicity of both engineered forms (termed as Round-shaped CCMV-VLPs and Rod-shaped CCMV-VLPs) as potential B cell immunogens using different in vitro and in vivo assays. Our results reveal that Round-shaped CCMV-VLPs are more efficient in draining to secondary lymphoid organs to charge professional antigen-presenting cells as well as B cells. Furthermore, compared to Rod-shaped CCMV-VLPs, Round-shaped CCMV-VLPs led to more than 100-fold increased systemic IgG and IgA responses accompanied by prominent formation of splenic germinal centers. Round-shaped CCMV-VLPs could also polarize the induced T cell response toward Th1. To our knowledge, this is the first study investigating and comparing the draining kinetics and immunogenicity of one and the same VLP monomer forming nano-sized icosahedra or rods in the micrometer size.
Simon Zinkhan, Anete Ogrina, Ina Balke, Gunta Reseviča, Andris Zeltins, Simone de Brot, Cyrill Lipp, Xinyue Chang, Lisha Zha, Monique Vogel, Martin F Bachmann, Mona O Mohsen

2771 related Products with: The impact of size on particle drainage dynamics and antibody response.

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