Feline calicivirus VP2 is involved in the self-assembly of the capsid protein into virus-like particles

Feline calicivirus (FCV) is considered the most common upper respiratory tract disease (URTD) associated pathogen in cats. We previously expressed FCV VP1 capsid protein in insect cells by baculovirus system and we observed that this protein self-assemble into virus-like particles (VLPs) different in size and lacking the typical cup-like depressions of caliciviruses. In the present study, VP1 and the small basic structural protein VP2 of FCV were individually expressed by baculovirus system. Coinfection of insect cells with both recombinant viruses resulted in VP1 and VP2 self-assembly to form depressions similar to native capsids in size and appearance, demonstrating that VP2 interacts with the VP1 protein in the formation of VLPs.