Potential for broad-spectrum protection against feline calicivirus using an attenuated myxoma virus expressing a chimeric FCV capsid protein

It has previously been demonstrated that recombinant myxoma viruses expressing FCV capsid protein are capable of eliciting protective responses against virulent FCV challenge, following vaccination, in cats. An attempt was made to produce a bivalent myxoma recombinant expressing the capsid protein genes of both FCV strains F9 and LS015. The FCV capsid protein genes were inserted into the myxoma growth factor gene (MGF) locus, and the serine protease inhibitor (SERP 2) gene locus. Subsequent recombination between myxoma-FCV viruses resulted in a recombinant expressing a chimeric form of the capsid protein. Nonetheless, cats immunised with this myxoma-FCV recombinant demonstrate high levels of serum neutralising antibodies against both F9 and LS015 strains. Such a chimeric vaccine may provide effective protection against a wide range of FCV strains.