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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Animal Parasitic Diseases Laboratory » Research » Publications at this Location » Publication #319382
Title: Phage-display for identifying peptides that bind the spike protein of transmissible gastroenteritis virus and possess diagnostic potential

Author
item SUO, SIQINGAOWA - Northeast Agricultural University
item WANG, XUE - Northeast Agricultural University
item Zarlenga, Dante
item RI-E, BU - Inner Mongolian Agriculture University
item REN, YUDONG - Northeast Agricultural University
item REN, XIAOFENG - Northeast Agricultural University

Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/27/2015
Publication Date: 5/27/2015
Citation: Suo, S., Wang, X., Zarlenga, D.S., Ri-E, B., Ren, Y., Ren, X. 2015. Phage-display for identifying peptides that bind the spike protein of transmissible gastroenteritis virus and possess diagnostic potential. Journal of Parasitology. 51(1):51-56.

Interpretive Summary: Transmissible gastroenteritis virus (TGEV) is comprised of a positive-stranded RNA genome. Piglets infected with TGEV exhibit high levels of morbidity and mortality where the mortality rate can reach 100%. Four structural proteins constitute the viral genome: the spike (S) protein, the integral membrane protein, the minor envelope protein, and the nucleocapsid protein. Among these, the S protein which contains four antigenic sites A, B, C and D, is the major host target for generating neutralizing antibodies to the virus. In the current study, we cloned and expressed a chimeric molecule consisting of the A and D portions of the S protein (rS-AD) which are most involved in the protective response, and used this recombinant protein to identify (pan) for peptides 12 amino acids in length and that bind to this region of the S protein. Among the many phage-expressed peptides we identified, three phages phTGEV-SAD-1, phTGEV-SAD-7 and phTGEV-SAD-15 encoding distinct peptides were identified that bind the spike protein. The phTGEV-SAD-15 bound most strongly to the virus and demonstrated its utility as a phage ELISA for diagnosing infections of TGEV. These data provide important information for developing a new and more sensitive test for TGEV and can be used by both scientists and commercial interest groups for advancing this goal.

Technical Abstract: The spike (S) protein is a key structural protein of coronaviruses including, the porcine transmissible gastroenteritis virus (TGEV). The S protein is a type I membrane glycoprotein located in the viral envelope and is responsible for mediating the binding of viral particles to specific cell receptors and therefore specific cell types. It is also an important immune target for the host in neutralizing the virus. Four antigenic sites A, B, C and D that reside near the N-terminal domain have been defined in the S protein. Of these, the region encoding antigenic sites A and to a lesser extent D, herein defined as S-AD, are most critical in eliciting host neutralizing antibodies. In the current study, we used a bacterially-expressed chimeric protein, rS-AD, as an immobilized target to identify peptides from a phage display library with application for diagnosis and or viral inhibition. Among the 9 phages selected that specifically bound to rS-AD, the phage phTGEV-SAD-15 bound with highest affinity and was subsequently used to develop a phage-based ELISA for TGEV. When compared with conventional antibody-based ELISA, phage-mediated ELISA was more sensitive; however, it did not perform better than semi-quantitative RT-PCR, though phage-mediated ELISA was quicker and easier to set up.