A genetically engineered chimeric vaccine against porcine circovirus type 2 (PCV2) is genetically stablein vitroandin vivo

• Published in: Vaccine Vol. 26; no. 33; p. 4231
• Main Authors: Gillespie, J, Juhan, NM, DiCristina, J, Key, KF, Ramamoorthy, S, Meng, XJ
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Limited 05.08.2008
• Subjects: Amino acids; Animal vaccines; Genes; Hogs; Mortality; Mutation; Swine; Vaccines
• ISSN: 0264-410X; 1873-2518
• DOI: 10.1016/j.vaccine.2008.05.051

A vaccine against porcine circovirus type 2 (PCV2), designated PCV1-2 chimera, was recently developed by replacing the capsid gene of the non-pathogenic PCV1 with that of PCV2. The PCV1-2 chimera virus is attenuated in pigs but induces protective immunity against PCV2. In this study, the genetic stability of the PCV1-2 chimera was evaluated for its potential use as a live vaccine. The PCV1-2 chimera virus was serially passaged 11 times in PK-15 cells and 3 times in pigs. The PCV1-2 chimera virus used in this study contained a tracking marker mutation in the capsid gene (F to V at amino acid position 79). Sequence analyses of the PCV1-2 chimera virus after 11 serial passages in PK-15 cells did not reveal any sequence change including the marker mutation. Similarly, there is no change in the genomic sequence of the PCV1-2 chimera virus recovered from pigs during 3 serialin vivopassages. Underin vivoselection pressure, however, the introduced tracking marker mutation in the PCV1-2 chimera quickly mutated (V79F) and restored to its original sequence after one passage in pigs, and remained stable in subsequent 2 passages in pigs. The results indicate that the PCV1-2 chimera virus is genetically stable, and thus should be a good vaccine candidate.