A Novel Peptide Screened by Phage Display Can Mimic TRAP Antigen Epitope against Staphylococcus aureus Infections

Guang Yang,Yaping Gao,Jie Dong,Chuan Liu,Yanning Xue,Ming Fan,Beifen Shen,Ningsheng Shao

doi:10.1074/jbc.m501127200

Guang Yang, Yaping Gao + Show 6 more

Open Access

https://doi.org/10.1074/jbc.m501127200

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Abstract

Staphylococcus aureus is a major human pathogen. Pathogenic effects are largely due to production of bacterial toxins, whose synthesis is controlled by an mRNA molecule termed RNAIII. The S. aureus protein called RAP (RNAIII-activating protein) is secreted and activates RNAIII production by inducing the phosphorylation of its target protein TRAP (target of RAP). Antibodies to TRAP have been shown to suppress exotoxin production by S. aureus in vitro, suggesting that TRAP may be a useful vaccine target site. Here we showed that a peptide TA21 was identified by screening a phage display library using anti-TRAP antibodies. Mice vaccinated with Escherichia coli engineered to express TA21 on their surface (FTA21) were protected from S. aureus infections, using sepsis and cellulitis mice models. By sequence analysis, it was found that the TA21 is highly homologous to the C-terminal sequence of TRAP which is conserved among S. aureus and Staphylococcus epidermidis, suggesting that peptide TA21 may be a useful broad vaccine to protect from infection caused by various staphylococcal strains.

Highlights

Staphylococcus aureus is a Gram-positive bacterium that can cause many different types of infectious diseases, ranging from minor skin infection to life-threatening deep infections such as pneumonia, endocarditis, meningitis, postoperative wound infections, septicemia, and toxin shock syndrome [1]
Pathogenic effects are largely due to production of bacterial toxins, whose synthesis is controlled by an mRNA molecule termed RNAIII
It was found that the TA21 is highly homologous to the C-terminal sequence of TRAP which is conserved among S. aureus and Staphylococcus epidermidis, suggesting that peptide TA21 may be a useful broad vaccine to protect from infection caused by various staphylococcal strains

Summary

EXPERIMENTAL PROCEDURES

Escherichia coli ER2537 was used as the host strain for the phage library (New England Biolabs). E. coli GI826 was purchased from Invitrogen Corp. Expression and Purification of Recombinant TRAPs (rTRAPs)—Two kinds of recombinant TRAP proteins were expressed in E. coli by using conventional methods. Purification of recombinant protein on a His tag binding resin was carried out accord-.

Novel Peptide Screened by Phage Display

RESULTS

No of mice that died

DISCUSSION