Comparative studies of the efficacy of a recombinant feline leukaemia virus vaccine

The efficacy of three feline leukaemia virus (FeLV) vaccines was compared. Kittens were immunised with either a recombinant subunit vaccine, Leucogen, or one of two inactivated virus vaccines, Leukocell 2 or Leucat. On subsequent challenge by intraperitoneal inoculation of FeLV of subgroup A (FeLV‐A), only Leucogen gave significant protection. In a second experiment, kittens vaccinated with Leucogen were protected against oronasal challenge with a phenotypic mixture of FeLV of subgroups A, B and C. These results indicate that a recombinant vaccine, containing only the protein moiety of the surface glycoprotein of FeLV‐A, can provide better protection than the inactivated virus vaccines tested against challenge with virus of the same subgroup, and can also protect against challenge by all three subgroups of FeLV.