VACCINATION OF CATS AGAINST THE FELINE LE UKEMIA-VIRUS (FELV) - 1ST RECOMBINANT VACCINE AND EFFECT OF A PREEXISTING INFECTION WITH THE FELINE IMMUNODEFICIENCY VIRUS (FIV)

A new recombinant FeLV vaccine was evaluated in 30 specified pathogen- free cats 10 months of age cats. The vaccine consisted of the non-glyc osylated FeLV envelope protein p45, aluminium hydroxide and a saponin adjuvant. The cats (n=18) were vaccinated twice intramuscularly, 3 wee ks apart. All animals were challenged intraperitoneally with FeLV subg roup A, 18 weeks later. While 94% of the vaccinated cats showed no vir aemia or were only transiently viraemic, 80% of the non-vaccinated ani mals became persistently viraemic within 2 to 3 weeks. In our hands th e preventable fraction of the vaccine was 93%. In order to determine t he effect of a pre-existing infection with feline immunodeficiency vir us on the efficacy of vaccination, 50% of the cats were previously inf ected with FIV. The infected cats were protected to the same degree as the non-infected animals. With prolonged duration of FIV infection th e probability increases, that the immune system of the cat will fail a nd clinical signs will appear. In order to observe a state of possible immunodeficiency, an accurate clinical examination of every cat prior to vaccination seems of major importance.