EFFECT OF DUAL-SUBTYPE VACCINE AGAINST FELINE IMMUNODEFICIENCY VIRUS-INFECTION

Dual-subtype feline immunodeficiency virus (FIV) vaccine, consisting o f inactivated cells infected with subtypes A (Petaluma strain) and D ( Shizuoka strain), was developed and tested for its vaccine efficacy ag ainst FIV infection in specific pathogen free (SPF) cats. Animals were monitored for proviral DNA by FIV-specific PCR and for FIV-specific a ntibody profiles by ELISA and virus-neutralization assays. In addition , blood from challenged cats was inoculated into naive SPF cats to con firm the viral status of the vaccinated cats. All cats immunized with Petaluma vaccine alone were protected against homologous Petaluma chal lenge, but only one of four cats was protected against heterologous Sh izuoka challenge. More importantly, all cats immunized with the dual-s ubtype vaccine were protected against both Petaluma and Shizuoka chall enges. These results suggest that a multi-subtype vaccine approach may provide the broad-spectrum immunity necessary for vaccine protection against strains from different subtypes. (C) 1997 Elsevier Science B.V .