Generation of porcine circovirus type 4 virus-like particles and their use to detect serum antibodies

Abstract

Abstract Porcine Circovirus type 4 (PCV4), first identified in 2019 as a newly emerging pathogen, has been found in several provinces of China, as well as in Korea and Thailand. Since PCV4 is not included in immunization programs, epidemiological investigations should be conducted for PCV4-positive antibodies detection. Virus-like particles (VLPs) are commonly employed for serological analysis of pathogen infections. However, there are no reports on using PCV4 VLPs in PCV4 infection investigation. In this study, we successfully generated self-assembled PCV4 VLPs using an E.coli expression system and purified the PCV4 VLPs through a two-step purification process. Subsequently, we utilized the purified VLPs as encapsulated antigens to develop an indirect ELISA. The established ELISA method showed high specificity, sensitivity, and repeatability, making it suitable for PCV4 antibodies investigation of serum samples. Finally, the ELISA was applied to detect 422 serum samples from regions in China, of which 134 tested positive. Therefore, PCV4-VLPs-based ELISA could effectively detect antibodies against PCV4 in serum samples, contributing to a better understanding of PCV4 epidemiology.