Abstract: The live recombinant avian vaccine comprises, as vector, an avian herpesvirus comprising at least one nucleotide sequence coding for and expressing an antigenic polypeptide of an avian pathogenic agent, inserted into the region lying between the ATG of ORF UL55 and the junction of U.sub.L with the adjacent repeat region, under the control of the CMV immediate early promoter. The vector is preferably chosen from the group consisting of Marek's disease viruses (MDV and HVT), infectious laryngotracheitis virus ILTV and herpes of ducks. A polyvalent vaccine formula comprises at least two vaccines of this type, with different inserted sequences.

Abstract: The recombinant live avian vaccine comprises as vector an ILTV virus comprising and expressing at least one heterologous nucleotide sequence, this nucleotide sequence being inserted into the insertion locus formed by the intergenic region located between the stop codons of ORF B and ORF C of ILTV, which region, in a particular strain of ILTV, is defined between nucleotides 908 and 994 in SEQ ID NO:1.

Abstract: The live recombinant avian vaccine comprises, as vector, an avian herpesvirus comprising at least one nucleotide sequence coding for and expressing an antigenic polypeptide of an avian pathogenic agent, inserted into the region lying between the ATG of ORF UL55 and the junction of U.sub.L with the adjacent repeat region, under the control of the CMV immediate early promoter. The vector is preferably chosen from the group consisting of Marek's disease viruses (MDV and HVT), infectious laryngotracheitis virus ILTV and herpes of ducks. A polyvalent vaccine formula comprises at least two vaccines of this type, with different inserted sequences.

Abstract: What is described is a modified vector, such as a recombinant poxvirus, particularly recombinant vaccinia virus, having enhanced safety. The modified recombinant virus has nonessential virus-encoded genetic functions inactivated therein so that virus has attenuated virulence. In one embodiment, the genetic functions are inactivated by deleting an open reading frame encoding a virulence factor. In another embodiment, the genetic functions are inactivated by insertional inactivation of an open reading frame encoding a virulence factor. What is also described is a vaccine containing the modified recombinant virus having nonessential virus-encoded genetic functions inactivated therein so that the vaccine has an increased level of safety compared to known recombinant virus vaccines.

Abstract: What is described is a modified vector, such as a recombinant poxvirus, particularly recombinant vaccinia virus, having enhanced safety. The modified recombinant virus has nonessential virus-encoded genetic functions inactivated therein so that virus has attenuated virulence. In one embodiment, the genetic functions are inactivated by deleting an open reading frame encoding a virulence factor. In another embodiment, the genetic functions are inactivated by insertional inactivation of an open reading frame encoding a virulence factor. What is also described is a vaccine containing the modified recombinant virus having nonessential virus-encoded genetic functions inactivated therein so that the vaccine has an increased level of safety compared to known recombinant virus vaccines.

Abstract: What is described is a modified vector, such as a recombinant poxvirus, particularly recombinant vaccinia virus, having enhanced safety. The modified recombinant virus has nonessential virus-encoded genetic functions inactivated therein so that virus has attenuated virulence. In one embodiment, the genetic functions are inactivated by deleting an open reading frame encoding a virulence factor. In another embodiment, the genetic functions are inactivated by insertional inactivation of an open reading frame encoding a virulence factor. What is also described is a vaccine containing the modified recombinant virus having nonessential virus-encoded genetic functions inactivated therein so that the vaccine has an increased level of safety compared to known recombinant virus vaccines.

Abstract: Herpesviruses naturally deficient in gD, that is to say not expressing their gD gene in vitro or not possessing this gene, are transformed to express gD in vitro. This transformation by genetic recombination can consist in replacement of the natural promoter by another one or insertion of an expression cassette containing gD and a promoter. The invention also relates to these viruses incorporating a gene coding for an antigen of interest, to the vaccines obtained and to the methods of culture thus improved. The invention relates in particular to avian herpesviruses, especially MDV, and the VZV virus.