PEG-8000 precipitation as a rapid method for enrichment and purification of feline calicivirus

Feline calicivirus (FCV) is widely used as a surrogate model to study calicivirus biology, including human noroviruses, for which robust cell culture systems are limited. The availability of concentrated and purified viral preparations is essential for structural, biochemical, and infectivity studies. Here, we describe and validate a polyethylene glycol (PEG-8000) precipitation method for the enrichment and purification of FCV from infected cell culture supernatants. PEG-8000 precipitation resulted in a more than 2-log increase in viral titers while markedly reducing contaminating cellular proteins. Purified viral particles retained infectivity and exhibited typical cytopathic effects, viral protein expression, and subcellular localization patterns during infection. Transmission electron microscopy confirmed the presence of non-enveloped viral particles with preserved morphology. Notably, both PEG-8000-purified and non-purified FCV preparations remained stable upon storage at -80 °C, maintaining infectivity after freezing. Compared with conventional ultracentrifugation-based approaches, this method is rapid, cost-effective, and does not require specialized equipment. Overall, PEG-8000 precipitation provides a reliable and straightforward strategy for FCV enrichment and purification and may be readily adapted for other members of the family Caliciviridae.