Location: Animal Parasitic Diseases LaboratoryTitle: Transmissible gastroenteritis virus; identification of M protein-binding peptide ligands with antiviral and diagnostic potential Author
Submitted to: Antiviral Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/22/2013
Publication Date: 9/30/2013
Citation: Zou, H., Zarlenga, D.S., Sestak, K., Suo, S., Ren, X. 2013. Transmissible gastroenteritis virus; identification of M protein-binding peptide ligands with antiviral and diagnostic potential. Antiviral Research. 99:383-390. Interpretive Summary: Transmissible gastroenteritis (TGE) is a highly contagious disease of swine characterized by up to 100% mortality in suckling piglets though pigs of all ages and categories are susceptible The clinical symptoms include acute diarrhea, vomiting and dehydration and the disease can cause devastating economic losses. The virus responsible for TGE (TGEV) has a glycoprotein surface envelope and positive-sense RNA genome of approximately 28.5 kb, and consists of four structural proteins: spike (S), small membrane (sM or E), membrane (M), and nucleocapsid (N) proteins. The M protein is one of the major structural proteins of all coronavirus particles. In this study, the M protein of TGEV was used to screen a phage display library expressing only small peptides on their surface. Three phages expressing TGEV-M-binding peptides were identified and characterized in more depth for their ability to differentiate TGEV infected pigs from animals infected with other common swine viruses. The ELISA-based test exhibited greater sensitivity than those currently available. Further, when one peptide was examined for antiviral activity, results showed that it was able to prevent TGEV infection in vitro if the virus was pretreated with the peptide. These results indicate that the TGEV peptide might be utilized for virus-specific diagnostics and antivirals. Both researchers and companies may find utility in further developing this assay as a method to diagnose and/or treat infected animals.
Technical Abstract: The membrane (M) protein is one of the major structural proteins of coronavirus particles. In this study, the M protein of transmissible gastroenteritis virus (TGEV) was used to biopan a 12-mer phage display random peptide library. Three phages expressing TGEV-M-binding peptides were identified and characterized in more depth. A phage-based immunosorbent assay (phage-ELISA) capable of differentiating TGEV from other coronaviruses was developed using one phage, phTGEV-M7, as antigen. When the phage-ELISA was compared to conventional antibody-based ELISA for detecting infections, phage-ELISA exhibited greater sensitivity. A chemically synthesized, TGEV-M7 peptide (pepTGEV-M7; HALTPIKYIPPG) was evaluated for antiviral activity. Plaque-reduction assays revealed that pepTGEV-M7 was able to abrogate TGEV infection in vitro (p<0.01) following pretreatment of the virus with the peptide. Indirect immunofluorescence and real-time RT-PCR confirmed the inhibitory effects of the peptide. These results indicate that pepTGEV-M7 might be utilized for virus-specific diagnostics and antivirals.