An improved method of deoptimization of nucleic acids, particularly nucleic acids associated with genes and/or open reading frames (ORFs) of a variety of pathogens including viruses, retroviruses, bacteria, fungi, and the like. Nucleic acids may be related to genes and/or ORFs from infectious viruses or other diseases and be associated with the elicitation of a protective response when inserted, using recombinant techniques, into a vector and used in a vaccine composition. The nucleic acid sequence of one or more ORFs may be optimized or deoptimized for use in an improved recombinant vaccine to elicit an immune response against an infectious agent when administered to a subject using a variety of dosing and timing regimens.

The present invention provides chimeric negative-stand RNA viruses that allow a subject, e.g., an avian, to be immunized against two infectious agents by using a single chimeric virus of the invention. In particular, the present invention provides chimeric influenza viruses engineered to express and incorporate into their virions a fusion protein comprising an ectodomain of a protein of an infectious agent and the transmembrane and cytoplasmic domain of an influenza virus protein. Such chimeric viruses induce an immune response against influenza virus and the infectious agent. The present invention also provides chimeric Newcastle Disease viruses (NDV) engineered to express and incorporate into their virions a fusion protein comprising the ectodomain of a protein of an infectious agent and the transmembrane and cytoplasmic domain of an NDV protein. Such chimeric viruses induce an immune response against NDV and the infectious agent.

The present disclosure provides, at least in part, methods and compositions for in vivo fusosome delivery. In some embodiments, the fusosome comprises a combination of elements that promote specificity for target cells, e.g., one or more of a fusogen, a positive target cell-specific regulatory element, and a non-target cell-specific regulatory element. In some embodiments, the fusosome comprises one or more modifications that decrease an immune response against the fusosome.

The invention provides methods for using virus-like particle (VLP) vaccines containing a stabilized pre-fusion respiratory syncytial virus (RSV) F protein to stimulate RSV neutralizing antibodies in pre-immune subjects. In one embodiment, the invention provides a method for immunizing a mammalian subject in need of immunizing against Respiratory Syncytial virus (RSV) infection, comprising, a) providing i) a pre-immune mammalian subject containing RSV neutralizing antibodies, ii) a first composition comprising recombinant chimeric Newcastle disease virus-like particles (ND VLPs), that contain a chimeric protein comprising, in operable combination, 1) stabilized pre-fusion RSV F protein ectodomain, 2) transmembrane (TM) domain of NDV F protein, and 3) cytoplasmic (CT) domain of NDV F protein, and b) administering an immunologically effective amount of the first composition to the pre-immune subject to produce an immunized subject that comprises an increase in the level of the RSV neutralizing antibodies compared to the level of RSV neutralizing antibodies in the pre-immune subject. In one embodiment, the level of the RSV neutralizing antibodies in the pre-immune subject does not prevent RSV infection of the pre-immune subject.

A vaccine includes a recombinant herpesvirus of turkeys (HVT) vector. The HVT vector has a heterologous polynucleotide coding for and expressing an Infectious Bursal Disease Virus (IBDV) viral protein 2 (VP2) antigen and a heterologous polynucleotide coding for and expressing an Infectious Laryngotracheitis Virus (ILTV) glycoprotein D (gD) antigen. The two heterologous polynucleotides are inserted into one locus in a non-essential region of the HVT genome selected from intergenic region 1 locus, intergenic region 2 locus, intergenic region 3 locus, UL43 locus, US10 locus, US2 locus, and SORF3/US2 locus. The two heterologous polynucleotides are linked by internal ribosome entry site (IRES). The expression of the two heterologous polynucleotides is driven by a cytomegalovirus (CMV) immediate early (IE) promoter.

The present disclosure provides, at least in part, methods and compositions for in vivo fusosome delivery. In some embodiments, the fusosome comprises a combination of elements that promote specificity for target cells, e.g., one or more of a fusogen, a positive target cell-specific regulatory element, and a non-target cell-specific regulatory element. In some embodiments, the fusosome comprises one or more modifications that decrease an immune response against the fusosome.

The present invention refers in general to the field of veterinary medicine and especially to the development of vectored vaccines using the Gallid alphaherpesvirus 3 (GaHV-3) or Marek's disease serotype 2 (MDV-2) vector, which contains protective antigens against different avian pathogens such as Newcastle disease virus (NDV), avian infectious laryngotracheitis virus (ILTV), infectious bursal disease virus (IBDV) or Gumboro disease virus, avian influenza virus (AIV), infectious bronchitis virus (IBV).

The present disclosure provides a recombinant herpesvirus of turkeys (HVT) and a preparation method and use thereof. The present disclosure specifically provides a recombinant HVT, where an exogenous gene is inserted in a spacer region between an HVT005 region and an HVT006 region of an HVT genome; and the exogenous gene is selected from a gene derived from the group consisting of a Newcastle disease virus (NDV), an avian influenza virus (AIV), and an infectious bursal disease virus (IBDV); the spacer region between an HVT005 region and an HVT006 region of an HVT genome is located between 8,867 nt and 9,319 nt of the HVT genome, and has a nucleotide sequence set forth in SEQ ID NO: 1.