Noninfectious Virus-Like Particle Antigen for Detection of Swine Vesicular Disease Virus Antibodies in Pigs by Enzyme-Linked Immunosorbent Assay

Abstract

An inactivated SVDV antigen is used in current enzyme-linked immunosorbent assays (ELISAs) for the detection of antibodies to swine vesicular disease virus (SVDV). To develop a noninfectious recombinant alternative, we produced SVDV-like particles (VLPs) morphologically and antigenically resembling authentic SVDV particles by using a dual baculovirus recombinant, which expresses simultaneously the P1 and 3CD protein genes of SVDV under different promoters. Antigenic differences between recombinant VLPs and SVDV particles were not statistically significant in results obtained with a 5B7-ELISA kit, indicating that the VLPs could be used in the place of SVDV antigen in ELISA kits. We developed a blocking ELISA using the VLPs and SVDV-specific neutralizing monoclonal antibody 3H10 (VLP-ELISA) for detection of SVDV serum antibodies in pigs. The VLP-ELISA showed a high specificity of 99.9% when tested with pig sera that are negative for SVDV neutralization (n ‫؍‬ 1,041). When tested using sera (n ‫؍‬ 186) collected periodically from pigs (n ‫؍‬ 19) with experimental infection with each of three different strains of SVDV, the VLP-ELISA detected SVDV serum antibodies as early as 3 days postinfection and continued to detect the antibodies from all infected pigs until termination of the experiments (up to 121 days postinfection). This test performance was similar to that of the gold standard virus neutralization test and indicates that the VLP-ELISA is a highly specific and sensitive method for the detection of SVDV serum antibodies in pigs. This is the first report of the production and diagnostic application of recombinant VLPs of SVDV. Further potential uses of the VLPs are discussed.

Efficient production of foot-and-mouth disease virus empty capsids in insect cells following down regulation of 3C protease activity

“…In some cases, sufficient empty capsid material has been prepared to immunise cattle and protection against homologous challenge was demonstrated (Li et al, 2008, 2011) but in the main the configuration of the P1and 3C coding sequences used to achieve empty capsid expression and the efficiency of capsid assembly has been highly variable, particularly in insect cells. For example, using the successful expression of swine vesicular disease empty capsids as an exemplar (Ko et al, 2005), usage of a dual promoter vector in which the P1 and 3C coding sequences of an O serotype of FMDV were under the control of the baculovirus polyhedrin and p10 promoters respectively, resulted in incomplete precursor cleavage and predominantly pentameric assemblies rather than complete capsids (Oem et al, 2007). Similarly, a dual expression strategy of an Asia 1 serotype of FMDV led to incomplete cleavage of the P1-2A precursor (Cao et al, 2009).…”

Virus-Like Particles, a Versatile Subunit Vaccine Platform

“…In addition, VLPs have also been produced from various non-human mammalian viruses, primarily for vaccination of livestock. Examples include porcine circovirus (Kim et al 2002 ), bovine rotavirus (RodriguezLimas et al 2011 ), chicken anaemia virus (Noteborn et al 1998 ;Koch et al 1995 ), SARS coronavirus (Liu et al 2011 ), Nipah virus (Walpita et al 2011 ), and swine vesicular stomatitis virus (Ko et al 2005 ).…”

Formation of virus-like particles from O-type foot-and-mouth disease virus in insect cells using codon-optimized synthetic genes

“…To date, numerous VLPs of different viruses, including swine vesicular disease virus (SVDV) (Ko et al 2005), enteroviruses (Hu et al 2003), hepatitis C virus (HCV) (Xiang et al 2002), poliovirus (Urakawa et al 1989), have been expressed using the baculovirus/insect cell expression system. Previously, we have also successfully expressed the VLPs of Asia 1 serotype FMDV in insect cells using the same expression system as described in the Materials and Methods section of this paper (Cao et al 2009).…”