Abstract: The invention comprises the nucleotide sequences comprising the FIPV S gene, or a fragment of this gene, which are modified in at least one of the antigenic regions A1 and A2 which are involved in enhancement, as well as the use of these sequences for the expression of modified proteins, and for the construction of recombinant viruses or expression plasmids, and the use of the recombinant viruses as vaccines against feline infectious peritonitis, the use of the expression plasmids as immunizing composition by direct injection of the said plasmids into cats, and the use of the modified proteins as vaccine.

Abstract: The present invention relates to vaccines for avian use which are based on live recombinant avian herpesviruses, in particular the Marek's disease viruses including HVT virus (herpesvirus of turkey), in which has been inserted, by genetic recombination, at least one nucleotide sequence which encodes and expresses an antigenic polypeptide of an avian pathogen under conditions which ensure immunization leading to efficient protection of the vaccinated animal against the pathogen. In one embodiment, the antigenic polypeptide is inserted in the UL43 gene under the control of the CMV immediate early promoter. The vaccines of the present invention are advantageous over previously used vaccines in that they can be used to ensure total protection of animals against Gumboro disease and to immunize chicks as young as one-day old without secondary effects, and only require low doses.