Expression of neutralizing epitope of porcine epidemic diarrhea virus in potato
plants
Young-Sook Kim
1
, Tae-Jin Kang
2
, Yong-Suk Jang
3
& Moon-Sik Yang
3,
*
1
Division of Biological Sciences and the Institute for Molecular Biology and Genetics;
2
Institute of Basic
Science;
3
Division of Biological Sciences and the Research Center for Bioactive Materials, Chonbuk National
University, Jeonju, Chonbuk 561–756, South Korea (* requests for offprints; Fax: +82-63-270-4334; E-mail:
mskyang@chonbuk.ac.kr)
Received 24 September 2004; accepted in revised form 3 December 2004
Key words: neutralizing epitope, plant expression, porcine epidemic, porcine epidemic diarrhea virus,
transgenic potato
Abstract
Transgenic plants expressing recombinant proteins from pathogenic microorganisms provide an inexpen-
sive edible vaccine for induction of local immunity. A neutralizing epitope of porcine epidemic diarrhea
virus (PEDV) gene containing SEKDEL was expressed in potato using Agrobacterium-mediated trans-
formation system. Putative transgenic plants were regenerated, and genomic PCR confirmed the presence
of PEDV epitope gene in the potato plants. Based on the ELISA results, epitope of PEDV protein made up
approximately 0.1% of the total soluble tuber protein.
Abbreviations: ELISA – enzyme linked immunosorbent assay; PEDV – porcine epidemic diarrhea virus;
TSP – total soluble protein
Introduction
The use of transgenic plants recently has been
proposed as an alternative to produce and deliver
vaccines. In comparison with injected vaccine,
plant-based vaccine systems have several advan-
tages; they are cheaper, easy to administer, have
longer shelf-life and are safer (Lauterslager et al.,
2001). Many papers have been published, that
antigens derived from various pathogens could be
synthesized at high levels and in their authentic
forms in plants (Arntzen, 1997; Kang et al., 2004;
Tacket, 2004).
Porcine epidemic diarrhea virus (PEDV) is
classified as a member of the Coronaviridae and
causes acute enteritis in pigs. The death rate of
piglets infected by PEDV is over 95%, and most
vaccines have been given parenterally to date. The
development of edible vaccines delivered to
mucosal surfaces could provide a safe method for
inducing modulated systemic immune responses
without injection-related hazards (Pizza et al.,
2001). In addition, the induction of mucosal im-
mune responses in feeders might be an effective
way of protecting them against PEDV infection,
since lactogenic immunity can protect suckling
piglets from PEDV infection (Pensaert, 1999).
The neutralizing epitope of PEDV was identi-
fied, based on the sequence information for the
neutralizing epitope of the transmissible gastro-
enteritis virus (TGEV), to test whether the oral
administration of the plants induced effective
protective immune responses against PEDV
infection (Chang et al., 2002). The identified neu-
tralizing epitope of PEDV was expressed in
tobacco by Agrobacterium-mediated transforma-
tion (Bae et al., 2003). Although the epitope of
PEDV expressed in tobacco plants has antigenic
Plant Cell, Tissue and Organ Culture (2005) 82: 125–130 Ó Springer 2005
DOI 10.1007/s11240-004-7203-7