Glycyrrhiza polysaccharide inhibits feline infectious peritonitis virus infection screened by a recombinant virus expressing eGFP protein

Abstract Background Feline infectious peritonitis (FIP) is a fatal infectious disease caused by feline infectious peritonitis virus (FIPV) which causes death of young cats less than 2 years old. Until now, few drugs are available for treatment of FIP. Here, we developed a modified FIPV expressing eGFP reporter gene by reverse genetics to evaluate the ability of Chinese herbal polysaccharides on inhibition of FIPV infection in Crandell-Rees feline kidney (CRFK) cells. Results The results demonstrated that the recombinant FIPV could express eGFP reporter gene, replicated in the CRFK cells and grow in a similar way with wild-type FIPV. By using this recombinant FIPV, we found that glycyrrhiza polysaccharide (GPS) effectively inhibited FIPV when added at the same time with virus or post-infection in CRFK cells. Further studies revealed that GPS inhibited FIPV adsorption and replication, but did not affect FIPV internalization in CRFK cells. Conclusions In the current study, we successfully established a modified FIPV platform which supports high-throughput drug screening in vitro, and we found that GPS is a promising candidate for treating FIP.