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Novel peptides screened by phage display peptide library can mimic epitopes of the FnBPA-A protein and induce protective immunity against Staphylococcus aureus in mice.

ABSTRACT: Fibronectin-binding protein A (FnBPA) is a key adhesin of Staphylococcus aureus, and the protein binding to fibrinogen and elastin is mediated by its N-terminal A domain. Thus, FnBPA-A has been considered a potential vaccine candidate, but the relevant epitopes are not fully understood. Here, purified rabbit anti-FnBPA-A antibodies were produced and used to screen for peptides corresponding to or mimicking the epitope of native FnBPA-A protein by using a phage random 12-mer peptide library. After four rounds of panning, 25 randomly selected phage clones were detected by phage-ELISA and competition-inhibition ELISA. Then, eight anti-rFnBPA-A antibody-binding phage clones were selected for sequencing, and six different 12-mer peptides were displayed by these phages. Although these displayed peptides shared no more than three consecutive amino acid residues identical to the sequence of FnBPA-A, they could be recognized by the FnBPA-A-specific antibodies in vitro and could induce specific antibodies against FnBPA-A in vivo, suggesting that these displayed peptides were mimotopes of FnBPA-A. Finally, the protective efficiencies of these mimotopes were investigated by mouse vaccination and challenge experiments. Compared with that of control group mice, the relative percent survival of mice immunized with phage clones displaying a mimotope was 13.33% (C2 or C15), 0% (C8), 6.67% (C10), 26.67% (C19 or 1:2 mixture of C23 and C19), 53.33% (C23), 33.33% (1:1 mixture of C23 and C19), and 66.67% (2:1 mixture of C23 and C19). Overall, five peptides mimicking FnBPA-A protein epitopes were obtained, and a partially protective immunity against S. aureus infection could be stimulated by these mimotope peptides in mice.

SUBMITTER: Li JN

PROVIDER: S-EPMC6813446 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature

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Novel peptides screened by phage display peptide library can mimic epitopes of the FnBPA-A protein and induce protective immunity against Staphylococcus aureus in mice.

Li Jin-Nian JN Wang Hong H Han Yu-Xi YX Zhao Yu-Ting YT Zhou Huan-Huan HH Xu Jun J Li Lin L

MicrobiologyOpen 20190826 10

Fibronectin-binding protein A (FnBPA) is a key adhesin of Staphylococcus aureus, and the protein binding to fibrinogen and elastin is mediated by its N-terminal A domain. Thus, FnBPA-A has been considered a potential vaccine candidate, but the relevant epitopes are not fully understood. Here, purified rabbit anti-FnBPA-A antibodies were produced and used to screen for peptides corresponding to or mimicking the epitope of native FnBPA-A protein by using a phage random 12-mer peptide library. Afte ...[more]

PMID: 31452334

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Project description:Coeliac disease (CD) is a common and complex disorder of the small intestine caused by intolerance to wheat gluten and related edible cereals like barley and rye. Peptides originating from incomplete gliadin digestion activate the lamina propria infiltrating T cells to release proinflammatory cytokines, which in turn cause profound tissue remodelling of the small intestinal wall. There is no cure for CD except refraining from consuming gluten-containing products.Phage from a random oligomer display library were enriched by repeated pannings against immobilised gliadin proteins. Phage from the final panning round were plated, individual plaques picked, incubated with host bacteria, amplified to a population size of 1011 to 1012 and purified. DNA was isolated from 1000 purified phage populations and the region covering the 36 bp oligonucleotide insert from which the displayed peptides were translated, was sequenced. Altogether more than 150 different peptide-encoding sequences were identified, many of which were repeatedly isolated under various experimental conditions. Amplified phage populations, each expressing a single peptide, were tested first in pools and then one by one for their ability to inhibit binding of human anti-gliadin antibodies in ELISA assays. These experiments showed that several of the different peptide-expressing phage tested inhibited the interaction between gliadin and anti-gliadin antibodies. Finally, four different peptide-encoding sequences were selected for further analysis, and the corresponding 12-mer peptides were synthesised in vitro. By ELISA assays it was demonstrated that several of the peptides inhibited the interaction between gliadin molecules and serum anti-gliadin antibodies. Moreover, ELISA competition experiments as well as dot-blot and western blot revealed that the different peptides interacted with different molecular sites of gliadin.We believe that several of the isolated and characterised gliadin-binding peptides described here could provide valuable tools for researchers in the field of CD by facilitating studies on localisation and uptake of various gliadin peptides in the small intestine. In future work, the potential of these peptides to detoxify gluten will be investigated.

Dataset Information

Novel peptides screened by phage display peptide library can mimic epitopes of the FnBPA-A protein and induce protective immunity against Staphylococcus aureus in mice.

Publications

Novel peptides screened by phage display peptide library can mimic epitopes of the FnBPA-A protein and induce protective immunity against Staphylococcus aureus in mice.

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