First isolation and genetic characterization of porcine circovirus type 3 using primary porcine kidney cells

Porcine circovirus type 3 (PCV3) was first detected in aborted fetuses in 2015 when sows displaying clinical signs that looked like porcine dermatitis and nephropathy syndrome died suddenly. Primary porcine kidney cells were selected for both the isolation and propagation of PCV3 strain SNUVR181115 (GenBank accession number MK503331) as these cells were permissive to PCV3 infection. PCV3 did not produce cytopathic effect on infected monolayers, therefore PCV3 infection was confirmed by in situ hybridization with a PCV3 specific DNA probe. Electron microscopy was used to analyze cell culture for the presence of virus. The intracytoplasmic inclusion bodies contained virus-like particles arranged in paracrystallline arrays on PCV3-infected primary porcine kidney cell. Virus replication peaked at 6th passage yielding titers close to 10(6) genomic copies of PCV3 per mL. PCV3 strain SNUVR181115 isolated from primary porcine kidney cells was highly conservative and was clustered with the Korean and Chinese strains. These results demonstrated that primary porcine kidney cells are useful for PCV3 isolation and replication.