RECOMBINANT HVT VECTORS EXPRESSING MULTIPLE ANTIGENS OF AVIAN PATHOGENS AND USES THEREOF

1 . A vaccine comprising a recombinant herpesvirus of turkeys (HVT) vector,

wherein the HVT vector comprises a first heterologous polynucleotide coding for and expressing an Infectious Bursal Disease Virus (IBDV) viral protein 2 (VP2) antigen and a second heterologous polynucleotide coding for and expressing an Infectious Laryngotracheitis Virus (ILTV) glycoprotein D (gD) antigen;

wherein the two heterologous polynucleotides are inserted into one locus in a non-essential region of the HVT genome selected from the group consisting of intergenic region 1 locus, intergenic region 2 locus, intergenic region 3 locus, UL43 locus, US10 locus, US2 locus, and SORF3/US2 locus;

wherein the two heterologous polynucleotides are linked by internal ribosome entry site (IRES); and

wherein the expression of the two heterologous polynucleotides is driven by a cytomegalovirus (CMV) immediate early (IE) promoter.

2 . The vaccine of claim 1 , wherein the IBDV VP2 antigen has at least 85% sequence identity to a polypeptide having the sequence as set forth in SEQ ID NO:2, wherein the ILTV gD antigen has at least 85% sequence identity to a polypeptide having the sequence as set forth in SEQ ID NO:17, and wherein the CMV IE promoter comprises a mouse cytomegalovirus (mCMV) IE promoter or a human cytomegalovirus (hCMV) IE promoter.

3 . The vaccine of claim 1 , wherein the CMV IE promoter is a mouse cytomegalovirus (mCMV) IE promoter, and the first heterologous polynucleotide is operably linked to the mCMV IE promoter at the 5′ end and the IRES at the 3′ end.

4 . The vaccine of claim 1 , wherein the non-essential region is the IG1 locus of the HVT genome.

5 . The vaccine of claim 1 , wherein the IBDV VP2 antigen has at least 90%, 95%, 96%, 97%, 98% or 99% sequence identity to a polypeptide having the sequence as set forth in SEQ ID NO:2.

6 . The vaccine of claim 1 , wherein the IBDV VP2 antigen has the polypeptide sequence as set forth in SEQ ID NO: 2.

7 . The vaccine of claim 1 , wherein the first heterologous polynucleotide encoding the IBDV VP2 antigen has at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% sequence identity to a polynucleotide having the sequence as set forth in SEQ ID NO: 1.

8 . The vaccine of claim 1 , wherein the first heterologous polynucleotide encoding the IBDV VP2 antigen has the sequence as set forth in SEQ ID NO: 1.

9 . The vaccine of claim 1 , wherein the ILTV gD antigen has at least 90%, 95%, 96%, 97%, 98% or 99% sequence identity to a polypeptide having the sequence as set forth in SEQ ID NO:17.

10 . The vaccine of claim 1 , wherein the ILTV gD antigen has the polypeptide sequence as set forth in SEQ ID NO: 17.

11 . The vaccine of claim 1 , wherein the second heterologous polynucleotide encoding the ILTV gD antigen has at least 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% sequence identity to a polynucleotide having the sequence as set forth in SEQ ID NO:16.

12 . The vaccine of claim 1 , wherein the second heterologous polynucleotide encoding the ILTV gD antigen has the sequence as set forth in SEQ ID NO: 16.

13 . The vaccine of claim 1 , wherein the expression of the ILTV gD antigen is regulated by the Simian virus 40 (SV40) poly A signal having the sequence as set forth in SEQ ID NO: 8.

14 . The vaccine of claim 1 , wherein the IRES has the sequence as set forth in SEQ ID NO: 10.

15 . The vaccine of claim 1 , further comprising a pharmaceutically or veterinarily acceptable carrier, excipient, vehicle or adjuvant.

16 . A method of inducing an immunological response in an animal against one or more antigens or a protective response in an animal against one or more avian pathogens, comprising inoculating the animal at least once with the vaccine of claim 1 .

17 . The method of claim 16 , wherein the animal is an avian, and the avian pathogen is selected from the group consisting of IBDV and ILTV.

18 . The method of claim 16 , wherein the vaccine is administered to one-day old chicks subcutaneously or intramuscularly.

19 . The method of claim 16 , wherein the vaccine is administered to an avian in ovo in 17-19 day-old embryos.

20 . A vaccine comprising a recombinant herpesvirus of turkeys (HVT) vector,

wherein the HVT vector comprises a first heterologous polynucleotide coding for and expressing an Infectious Bursal Disease Virus (IBDV) viral protein 2 (VP2) antigen and a second heterologous polynucleotide coding for and expressing an Infectious Laryngotracheitis Virus (ILTV) glycoprotein D (gD) antigen;

wherein the first heterologous polynucleotide has the sequence as set forth in SEQ ID NO: 1, and the second heterologous polynucleotide has the sequence as set forth in SEQ ID NO: 16;

wherein the two heterologous polynucleotides are inserted into intergenic region 1 locus (IG1 locus) of the HVT genome;

wherein the two heterologous polynucleotides are linked by internal ribosome entry site (IRES) having the sequence as set forth in SEQ ID NO: 10;

wherein the first heterologous polynucleotide is operably linked to a mouse cytomegalovirus (mCMV) immediate early (IE) promoter at the 5′ end, and the IRES at the 3′ end;

wherein the expression of the two heterologous polynucleotides is driven by the mCMV IE promoter; and

wherein the expression of the ILTV gD antigen is regulated by the SV40 poly A signal having the sequence as set forth in SEQ ID NO: 8.