Development of probes to differentiate porcine circovirus types 1 and 2 invitro by in situ hybridization

Porcine circovirus type 1 (PCV1), a PK-15 cell line contaminant, and porcin e circovirus type 2 (PCV2), associated with post-weaning multisystemic wast ing syndrome (PMWS), are genetically and antigenically related. Several tec hniques have been developed to detect PCV, including in situ hybridization (ISH). Previously reported probes used for ISH may hybridize with both PCV1 and PCV2 nucleic acids. We attempted to produce probes for ISH that can de tect and differentiate PCV2 from PCV1 in PCV-infected cells. Riboprobes wer e synthesized from the sense and antisense strands of both open reading fra mes 1 and 2 (ORF1 and ORF2) of PCV2. At 42 and 58 degrees C, the ORF1 antis ense probe hybridized with nucleic acid from both PCV1- and PCV2-infected c ells. At 58 degrees C, the ORF2 antisense probe hybridized with PCV2 nuclei c acid but not with PCV1 nucleic acid. The ORF1 and ORF2 sense probes bound only with PCV2 nucleic acid. Both antisense strand probes produced stronge r signals than the sense strand probes. The results showed that the PCV2 OR F1 antisense probe is the most likely probe to detect both PCV types while the ORF2 antisense probe is capable of discriminating between PCV1 and PCV2 . Published by Elsevier Science B.V.