Identification of novel immunodominant proteins from Campylobacter jejuni and the characterization of linear epitopes
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ABSTRACT:
ORGANISM(S): Campylobacter jejuni subsp. jejuni NCTC 11168 = ATCC 700819
PROVIDER: GSE44717 | GEO | 2013/04/06
SECONDARY ACCESSION(S): PRJNA193418
REPOSITORIES: GEO
Similar Datasets
Project description:This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
2013-04-06 | E-GEOD-44717 | biostudies-arrayexpress
Project description:Campylobacter jejuni remains one of the major gut pathogens of our time. Its zoonotic nature and wide-spread distribution in industrialized countries calls for a quick and reliable diagnostic tool. Antibody-based detection presents a suitable means to identify pathogenic bacteria. However, the knowledge about immunodominant targets is limited. Thus, an approach is presented, which allows for the rapid screening of numerous cDNA derived expression clones to identify novel antigens. The deeper understanding of immunodominant proteins assists in the design of diagnostic tools and furthers the insight into the bacterium's pathogenicity as well as revealing potential candidates for vaccination. We have successfully screened 1536 clones of an expression library to identify 22 proteins that have not been described as immunodominant before. After subcloning the corresponding 22 genes and expression of full-length proteins, we investigated the immunodominant character by microarrays and ELISA. Subsequently, seven proteins were selected for epitope mapping. For cj0669 and cj0920c linear epitopes were identified. For cj0669, specificity assays revealed a specific linear epitope site. Consequently, an eleven amino acid residue sequence TLIKELKRLGI was analyzed via alanine scan, which revealed the glycine residue to be significant for binding of the antibody. The innovative approach presented herein of generating cDNAs of prokaryotes in combination with a microarray platform rendering time-consuming purification steps obsolete has helped to illuminate novel immunodominant proteins of C.jejuni. The findings of a specific linear epitope pave the way for a plethora of future research and the potential use in diagnostic applications such as serological screenings. Moreover, the current approach is easily adaptable to other highly relevant bacteria making it a formidable tool for the future discovery of antigens and potential biomarkers. Consequently, it is desirable to simplify the identification of structural epitopes, as this would extend the spectrum of novel epitopes to be detected.
| S-EPMC3667084 | biostudies-literature
Project description:The screening of a cDNA derived expression library of Campylobacter jejuni NCTC 11168 expressed in E. coli using a fusion construct and specific HaloTag interaction to a modified surface is shown. 1536 different clones were screened including positive (hisJ, cjaA, peb1a) and negative (argC, pyrC, gapA) reference proteins. The goal of the screening was to identify potential novel immunogenic proteins from C. jejuni by selecting clones showing a high signal intensity in comparison to the known antigens used as positive markers. Afterwards, the most promising clones were sequenced to identify the gene and corresponding protein, and these proteins were then investigated further. Consequently, 22 novel immunogenic proteins could be identified.
2013-04-06 | GSE45268 | GEO
Project description:A number of seven proteins were selected during immunoscreening and further analyses. The proteins were in silico divided into overlapping 15-mer oligopeptides with an overlap of 11 residues. The microarrays were incubated with different antibodies to C. jejuni, Escherichia coli and Salmonella enterica.
2013-04-06 | GSE45542 | GEO
Project description:The screening of a cDNA derived expression library of Campylobacter jejuni NCTC 11168 expressed in E. coli using a fusion construct and specific HaloTag interaction to a modified surface is shown. 1536 different clones were screened including positive (hisJ, cjaA, peb1a) and negative (argC, pyrC, gapA) reference proteins. The goal of the screening was to identify potential novel immunogenic proteins from C. jejuni by selecting clones showing a high signal intensity in comparison to the known antigens used as positive markers. Afterwards, the most promising clones were sequenced to identify the gene and corresponding protein, and these proteins were then investigated further. Consequently, 22 novel immunogenic proteins could be identified. In total, 1536 (4 x 384) different lysates were spotted on different microarray slides. Each slide contained 3600 distinct spots, separated into two compartments of 1800 spots each. Each compartment comprised quadruplicate replicates of each sample lysate with controls being analysed with more replicates. As controls we used: hisJ, cjaA and peb1 (3 x 40 replicates) as positive reference proteins, as they have been described as immunogenic before; argC and pyrC (2 x 40 replicates) as negative reference proteins; two sets of E. coli cell lysates without fusion proteins expressed, namely Acella electrocompetent cells (40 replicates) and KRX (32 replicates); and a buffer control (24 replicates). Therefore, each set of replicate slides contained 376 different samples and 8 controls. Each screening was performed with three replicate slides. Consequently, a total number of 12 slides were screened (4 sets of samples x 3 replicates each). For identification, rabbit polyclonal antibody to C. jejuni (Acris AP24002PU-N) as primary and goat polyclonal to rabbit IgG conjugated with ChromeoTM-546 (Abcam ab60317) as secondary antibody were used. The top compartment was incubated first with primary antibody, while the bottom compartment was incubated with PBS at the same time. Afterwards, both compartments were incubated with secondary antibody.
2013-04-06 | E-GEOD-45268 | biostudies-arrayexpress
Project description:A novel severe acute respiratory syndrome coronavirus (SARS-CoV-2) is the source of a current pandemic (COVID-19) with devastating consequences in public health and economic stability. Using a peptide array to map the antibody response of plasma from healing patients (12) and heathy patients (6), we identified three immunodominant linear epitopes, two of which correspond to key proteolytic sites on the spike protein (S1/S2 and S2') known to be critical for cellular entry. We show biochemical evidence that plasma positive for the epitope adjacent to the S1/S2 cleavage site inhibits furin-mediated proteolysis of spike.
| S-EPMC7480855 | biostudies-literature
Project description:A number of seven proteins were selected during immunoscreening and further analyses. The proteins were in silico divided into overlapping 15-mer oligopeptides with an overlap of 11 residues. The microarrays were incubated with different antibodies to C. jejuni, Escherichia coli and Salmonella enterica. Each microarray was separated into three individual incubation chambers using ProPlate 3-Well modules. Within each incubation chamber, each peptide was spotted in triplicate with the controls spotted nine times each. The controls included human-IgG, rabbit-IgG, mouse-IgG and myelin basal protein (MBP). Each chamber was incubated independently using different polyclonal antibodies to C. jejuni, and for specificity testing, with an antibody to E. coli or S. enterica. Thus, samples 4_1, 4_2, 5_1 and 5_2 represent epitope mapping of three proteins with C. jejuni antibodies, while 6_1, 6_2, 7_1 and 7_2 represent the data after incubation with an E. coli antibody investigating unspecific interactions of the antibody to the potential linear epitopes from C. jejuni. Finally, for four different proteins from C. jejuni, the set two indicated by S2 was performed. Here, S2_6_1, S2_7_1, S2_7_2, S2_8_1 and S2_8_2 indicate epitope mapping after incubation with antibodies to C. jejuni, while the remaining samples were performed to test these latter 4 proteins for specificity by incubation with antibody to S. enterica.
2013-04-06 | E-GEOD-45542 | biostudies-arrayexpress
Project description:Campylobacter jejuni is one of the leading bacterial causes of food-borne gastroenteritis. Infection with C. jejuni is frequently acquired through the consumption of undercooked poultry or foods cross-contaminated with raw poultry. Given the importance of poultry as a reservoir for Campylobacter organisms, investigators have performed studies to understand the protective role of maternal antibodies in the ecology of Campylobacter colonization of poultry. In a previous study, chicks with maternal antibodies generated against the S3B strain of C. jejuni provided protection against Campylobacter colonization (O. Sahin, N. Luo, S. Huang, and Q. Zhang, Appl. Environ. Microbiol. 69:5372-5379, 2003). We obtained serum samples, collectively referred to as the C. jejuni S3B-SPF sera, from the previous study. These sera were determined to contain maternal antibodies that reacted against C. jejuni whole-cell lysates as judged by enzyme-linked immunosorbent assay. The antigens recognized by the C. jejuni S3B-SPF antibodies were identified by immunoblot analysis, coupled with mass spectrometry, of C. jejuni outer membrane protein extracts. This approach led to the identification of C. jejuni proteins recognized by the maternal antibodies, including the flagellin proteins and CadF adhesin. In vitro assays revealed that the C. jejuni S3B-SPF sera retarded the motility of the C. jejuni S3B homologous strain but did not retard the motility of a heterologous strain of C. jejuni (81-176). This finding provides a possible mechanism explaining why maternal antibodies confer enhanced protection against challenge with a homologous strain compared to a heterologous strain. Collectively, this study provides a list of C. jejuni proteins against which protective antibodies are generated in hens and passed to chicks.
| S-EPMC2583476 | biostudies-literature
Project description:Although vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are under development, the antigen epitopes on the virus and their immunogenicity are poorly understood. Here, we simulate the 3D structures and predict the B cell epitopes on the spike (S), envelope (E), membrane (M), and nucleocapsid (N) proteins of SARS-CoV-2 using structure-based approaches and validate epitope immunogenicity by immunizing mice. Almost all 33 predicted epitopes effectively induce antibody production, six of these are immunodominant epitopes in individuals, and 23 are conserved within SARS-CoV-2, SARS-CoV, and bat coronavirus RaTG13. We find that the immunodominant epitopes of individuals with domestic (China) SARS-CoV-2 are different from those of individuals with imported (Europe) SARS-CoV-2, which may be caused by mutations on the S (G614D) and N proteins. Importantly, we find several epitopes on the S protein that elicit neutralizing antibodies against D614 and G614 SARS-CoV-2, which can contribute to vaccine design against coronaviruses.
| S-EPMC7837128 | biostudies-literature
Project description:We cloned and expressed in Escherichia coli a gene encoding an 18-kDa outer membrane protein (Omp18) from Campylobacter jejuni ATCC 29428. The nucleotide sequence of the gene encoding Omp18 was determined, and an open reading frame of 165 amino acids was revealed. The amino acid sequence had the typical features of a leader sequence and a signal peptidase II cleavage site at the N-terminal part of Omp18. Moreover, the sequence had a high degree of similarity to the peptidoglycan-associated outer membrane lipoprotein P6 of Haemophilus influenzae and the peptidoglycan-associated lipoprotein PAL of E. coli. Southern blot analysis in which the cloned gene was used as a probe revealed genes similar to that encoding Omp18 in all species of the thermophilic group of campylobacters as well as Campylobacter sputorum. All campylobacters tested expressed a protein with a molecular mass identical to that of Omp18. The protein reacted immunologically with polyclonal antibodies directed against Omp18 from C. jejuni. PCR amplification of the gene encoding Omp18 with specific primers and subsequent restriction enzyme analysis of the amplified DNA fragments showed that the gene for Omp18 is highly conserved in C. jejuni strains isolated from humans, dogs, cats, calves, and chickens but is different in other Campylobacter species. In order to obtain pure recombinant Omp18 protein for serological assays, the cloned gene for Omp18 was genetically modified by replacing the signal sequence with a DNA segment encoding six adjacent histidine residues. Expression of this construct in E. coli allowed purification of the modified protein (Omp18-6xHis) by metal chelation chromatography. Sera from patients with past C. jejuni infection reacted positively with Omp18-6xHis, while sera from healthy blood donors showed no reaction with this antigen. Omp18, which is an outer membrane protein belonging to the family of PALs is well conserved in C. jejuni and is highly immunogenic. It is therefore a good candidate as an antigen for the serological diagnosis of past C. jejuni infections.
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