Establishment and Evaluation of Enzyme-Linked Immunosorbent Assay for Detection of Porcine Circovirus Type 2

C Wang1,2*, VF Pang2, F Lee1, YL Lin1, SS Lai2, CR Jeng2

1Animal Health Research Institute, Council of Agriculture, Executive Yuan

2School of Veterinary Medicine, National Taiwan University

Abstract

Post-weaning multi-systemic wasting syndrome (PMWS) has emerged as a major disease that poses a significant threat to the economics of the global swine industry. Porcine circovirus type 2 (PCV2) is the causative agent of PMWS in pigs. PK-15 cell culture, which is widely used for PCV2 propagation, is not efficient and heterogeneous in terms of permissivity to viral infection. To acquire a homogeneous porcine kidney cell line that can reliably produce PCV2, PK-15 parent cells were re-cloned by limiting dilutions for PCV2 propagation. Maximum virus titers in newly generated PK-15 and PK-15 parent cells were 106.5 and 104 tissue culture infective dose 50 (TCID50)/ml, respectively. In addition, a PCV2 indirect enzyme-linked immunosorbent assay (iELISA) based on PK-15 -generated PCV2 was developed for the detection of antibodies to PCV2. This method was highly specific for PCV2. No cross-reaction to porcine reproductive and respiratory syndrome virus (PRRSV), pseudorabies virus (PRV) and classical swine fever virus (CSFV) was observed. A total of 385 porcine sera were tested using both iELISA and a commercial sandwich ELISA (sELISA). The sensitivity and specificity of ELISA relative to those of sELISA were 97.8% and 90.7%, respectively. The percentage of observed agreement was 95.8%, and the kappa statistic was 0.86. These results indicated that iELISA was a specific and sensitive diagnostic method for the detection of PCV2 antibodies in clinical porcine sera.

Keywords: porcine circovirus type 2, specificity, sensitivity.