RESUMO
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.
Assuntos
Infecções por Caliciviridae/imunologia , Infecções por Caliciviridae/veterinária , Calicivirus Felino/imunologia , Proteínas do Capsídeo/imunologia , Doenças do Gato/imunologia , Doenças do Gato/prevenção & controle , Proteínas Mutantes Quiméricas/imunologia , Myxoma virus/imunologia , Animais , Antígenos Virais/imunologia , Infecções por Caliciviridae/prevenção & controle , Calicivirus Felino/ultraestrutura , Proteínas do Capsídeo/genética , Gatos , Linhagem Celular , Microscopia Eletrônica , Proteínas Mutantes Quiméricas/genética , Myxoma virus/genética , Testes de Neutralização , Plasmídeos/genética , Coelhos , Vacinas Atenuadas/imunologia , Vacinas Sintéticas/imunologiaRESUMO
Myxoma virus, a member of the Poxviridae family (genus Leporipoxvirus) is the agent responsible for myxomatosis in the European rabbit. Recombinant myxoma viruses expressing the capsid gene of an F9 strain of feline calicivirus (FCV) were constructed from an apathogenic, laboratory attenuated, isolate of myxoma virus. The FCV capsid genes were recombined into the myxoma growth factor (MGF) locus of the myxoma genome and expressed from synthetic poxvirus promoters. Myxoma virus is unable to replicate productively in feline cells in vitro, however, cells infected with recombinant viruses do express the heterologous antigens from both late and early/late synthetic promoters. Cats immunised with myxoma-FCV recombinant virus generated high levels of serum neutralising antibody and were protected from disease on subsequent challenge with virulent FCV. Furthermore, there was no evidence of transmission of myxoma-FCV recombinant virus from vaccinated to non-vaccinated cats. These results demonstrate the potential of myxoma virus as a safe vaccine vector for use in non-lepori species and in particular the cat.
