MULTIVALENT HVT VECTOR VACCINE
The present invention regards recombinant HVT (rHVT) constructs, useful as multivalent vector vaccine for poultry. The rHVT comprise 4 heterologous genes from poultry pathogens: the VP2 gene from IBDV, the F gene from NDV, and the gD and gI genes from ILTV. The VP2 and F genes are inserted in the Us genome region of the rHVT. The gD-gI genes are inserted in the UL genome region, either between UL44 and UL45, or between UL45 and UL46. The rHVTs proved to be genetically stable in vitro and in vivo, and expressed all inserted genes well enough to induce protective immunity in vaccinated poultry against IBDV, NDV, and ILTV.
1 . Recombinant herpesvirus of turkeys (rHVT) expressing an infectious bursal disease virus (IBDV) viral protein 2 (VP2) gene and a Newcastle disease virus (NDV) fusion (F) protein gene from a first expression cassette which is inserted in the unique short (Us) region of the genome of the rHVT, characterised in that said rHVT also expresses a glycoprotein D and a glycoprotein I (gD and gI) gene off infectious laryngotracheitis virus (ILTV) from a second expression cassette which is inserted in the unique long (UL) region of the genome of said rHVT, either between the UL44 and UL45 genes or between the UL45 and UL46 genes.
2 . The rHVT according to claim 1 , characterised in that the first expression cassette comprises in 5′ to 3′ direction and in this order:
a. a murine cytomegalovirus immediate early 1 gene (mCMV-IE1) promoter,
b. an IBDV VP2 gene,
c. a transcription terminator,
d. a human cytomegalovirus immediate early 1 gene (hCMV-IE1) promoter,
e. an NDV F protein gene, and
f. a transcription terminator,
and whereby the promoters and terminators are operatively linked to the VP2 gene respectively to the F gene.
3 . The rHVT according to claim 1 , characterized in that the first expression cassette is inserted in the Us2 gene.
4 . The rHVT according to claim 1 , characterised in that the second expression cassette comprises in 5′ to 3′ direction and in this order:
a. an ILTV gD gene with an upstream promoter and a downstream terminator, and
b. an ILTV gI gene with an upstream promoter and a downstream terminator, and whereby the promoters and terminators are operatively linked to the gD gene respectively to the gI gene.
5 . A host cell comprising the rHVT according to claim 1 .
6 . (canceled)
7 . A Vaccine for poultry comprising the rHVT according to claim 1 , and a pharmaceutically acceptable carrier.
8 . The vaccine according to claim 7 , comprising at least one additional immunoactive component.
9 . Method for the preparation of a vaccine for poultry, said method comprising the steps of:
a. infecting host cells in vitro with the rHVT according to claim 1
b. harvesting the infected host cells, and
c. mixing the harvested infected host cells with a pharmaceutically acceptable carrier.
10 .- 11 . (canceled)
12 . Method for preventing or reducing infection by MDV, IBDV, NDV and/or ILTV, or their associated signs of disease, the method comprising the administration of the vaccine according to to claim 7 poultry.
13 . (canceled)
14 . A vaccine for poultry comprising the host cell according to claim 5 , and a pharmaceutically acceptable carrier.
15 . Method for preventing or reducing infection by MDV, IBDV, NDV and/or ILTV, or their associated signs of disease, the method comprising the administration of the vaccine according to claim 14 to poultry.