Experimental production of synthetic infectious porcine circovirus 2b particles in swine testicular cells

Abstract

Porcine circoviruses (PCV) are widespread in the global swine population and is notable for having the smallest known viral genome and structure. Among its species, porcine circovirus 2 (PCV2) is particularly significant due to its association with porcine circovirus diseases (PCVD), a group of syndromes affecting various organs, with the most common symptom being reduced zootechnical performance. Monitoring and preventing this infection are crucial to reducing economic losses and improving animal welfare. In this context, producing synthetic infectious PCV2b particles from a fully designed genome allows insights into the virus's structure and biology. This approach could facilitate the development of engineered viruses for diverse biotechnological applications, such as novel vaccine candidates and diagnostic assay components. The main objective of this study was to standardize the procedures for generating synthetic viral particles in cell culture from a synthetic viral genome. To achieve this, we transfected the synthetic genome into swine testicular (ST) cells and maintained them under optimal conditions, subcultivating the cells to support growth. After transfection, a cell culture infection assay was conducted using the supernatant from the transfected cells. Viral DNA from transfected and infected cultures was quantified by quantitative polymerase chain reaction (qPCR), antigen production was assessed by enzyme-linked immunosorbent assay (ELISA), and the surface structure of the synthetic viral particles was visualized by transmission electron microscopy with negative staining. The results strongly support the successful production of infectious synthetic PCV2b particles, enabling their use in biotechnological applications for this and related species.