Chimeric Porcine Circoviruses (PCV) Containing Amino Acid Epitope Tags in the C Terminus of the Capsid Gene Are Infectious and Elicit both Anti-Epitope Tag Antibodies and Anti-PCV Type 2 Neutralizing Antibodies in Pigs

Abstract

A chimeric porcine circovirus (PCV1-2) with the capsid gene of pathogenic PCV2 cloned into the genomic backbone of nonpathogenic PCV1 is attenuated in pigs but elicits protective immunity against PCV2. In this study, short epitope tags were inserted into the C terminus of the capsid protein of the chimeric PCV1-2 vaccine virus, resulting in a tractable marker virus that is infectious both in vitro and in vivo. Pigs experimentally infected with the epitope-tagged PCV1-2 vaccine viruses produced tag-specific antibodies, as well as anti-PCV2 neutralizing antibodies, indicating that the epitope-tagged viruses could potentially serve as a positive-marker modified live-attenuated vaccine.

Construction and characterization of 3A-epitope-tagged foot-and-mouth disease virus

“…The introduction of foreign epitopes into viral genome can facilitate the purification of virus particles (Prentoe and Bukh, 2011;Wegelt et al, 2011) and is also convenient for the studies about intracellular location (Brennan et al, 2011) of viral protein, the role of the viral protein in the virus life cycle (Brennan et al, 2011), the interactions of virus protein with viral and cellular protein in infected cells (Teterina et al, 2011). Moreover, the chimeric viruses containing foreign epitopes could potentially serve as positive-marker vaccines (Beach et al, 2011;Holinka et al, 2009). In FMDV, the role of the 3A protein in the virus life cycle, the function of the residues 93-102 of 3A on host range, and the interactions of 3A with other viral proteins and host proteins are currently unclear.…”

Emerging and Re-emerging Swine Viruses

“…Although PCV2a and PCV2b differ by as much as 10% nucleotide sequence identity, the current PCV2a‐based vaccines appear to provide sufficient level of cross‐protection against PCV2b (Fort et al., 2009; Beach et al., 2010a,b). An experimental PCV2b‐based vaccine has been developed and shown to confer homologous protection against PCV2b and heterologous protection against PCV2a (Beach et al., 2010b, 2011a). Thus far, the PCV2 vaccines are effective, although rare cases of vaccine failure have been reported in a few herds, presumably due to off‐label uses of the vaccines and other unknown reasons.…”

Affinity Proteomics to Study Endogenous Protein Complexes: Pointers, Pitfalls, Preferences and Perspectives

“…Small tags (~1–5 kDa) are commonly favored in affinity capture, although it is not clear that larger-sized tags offer any comparative disadvantages for most applications. When tagging in compact genomes, such as those of viruses, additional genetic sequences may not be tolerated, and therefore only small tags placed at specific locations should be used (22–24). We observed this when surveying viable tags for affinity capture of L1 retrotransposons, which have a ~6 kb genome encoding two polypeptides; inserting larger tags corresponded to reduced efficiency of transposition (25).…”