The invention is related to a dengue virus or chimeric dengue virus that contains a mutation in the 3′ untranslated region (3′-UTR) comprising a Δ30 mutation that removes the TL-2 homologous structure in each of the dengue virus serotypes 1, 2, 3, and 4, and nucleotides additional to the Δ30 mutation deleted from the 3′-UTR that removes sequence in the 5′ direction as far as the 5′ boundary of the TL-3 homologous structure in each of the dengue serotypes 1, 2, 3, and 4, or a replacement of the 3′-UTR of a dengue virus of a first serotype with the 3′-UTR of a dengue virus of a second serotype, optionally containing the Δ30 mutation and nucleotides additional to the Δ30 mutation deleted from the 3′-UTR; and immunogenic compositions, methods of inducing an immune response, and methods of producing a dengue virus or chimeric dengue virus.

Described herein are improved purification methods for Zika virus vaccines and compositions. Also described are Zika vaccines and methods of producing and administering said Zika vaccines to subjects in need thereof.

A Dengue virus Envelope Dimer Epitope (EDE) wherein the EDE: c) spans the polypeptides of a Dengue virus Envelope polypeptide dimer; and/or d) is presented on a dimer of Envelope proteins; and/or c) is formed from consecutive or nonconsecutive residues of the envelope polypeptide dimer, wherein the dimer is a homodimer or heterodimer of native and/or mutant envelope polypeptides, from any one or two of DENV-1, DENV-2, DENV-3 and DENV-4. The EDE may be a stabilized recombinant dengue virus envelope glycoprotein E ectodomain (sE) dimer, wherein the dimer is: covalently stabilized with at least one disulphide inter-chain bond between the two sE monomers, and/or covalently stabilized with at least one sulfhydryl-reactive crosslinker between the two sE monomers, and/or covalently stabilized by linking the two sE monomers through modified sugars; and/or, covalently stabilised by being formed as a single polypeptide chain, optionally with a linker region, optionally a Glycine Serine rich linker region, separating the sE sequences, and/or non-covalently stabilized by substituting at least one amino acid residue in the amino acid sequence of at least one sE monomer with at least one bulky side chain amino acid, at the dimer interface or in domain 1 (D1)/domain 3 (D3) linker of each monomer. A compound, for example an antibody or antibody fragment that can neutralise more than one Dengue virus serotype, for example an antibody that can bind to an EDE of the invention.

The disclosure concerns a polypeptide suitable for detecting antibodies against Zika virus in an isolated biological sample having a Zika virus NS1 wing domain specific amino acid sequence and variants thereof, wherein no further Zika virus specific amino acid sequences are present in the polypeptide. This polypeptide does not immunologically cross-react with antibodies raised against structurally related antigens from tick-borne encephalitis virus, Dengue virus 1-4, West Nile virus, yellow fever virus or Japanese encephalitis virus, but immunologically reacts with antibodies raised against full length Zika virus NS1 antigen. Also disclosed is a method of producing a soluble and immunoreactive Zika virus NS1 polypeptide as well as methods and kits for detecting antibodies specific for Zika virus in an isolated sample.

The present invention is directed to a Zika virus (ZIKV) chimeric polyepitope comprising non-structural proteins and its use in an immunogenic composition. The present invention provides means, in particular polynucleotides, vectors and cells expressing said chimeric polyepitope. The present invention also relates to a composition or a vaccine comprising at least one of said polyepitope, polynucleotide, vector or host cell for use in the prevention of a ZIKV infection in a human subject, or for use in the prevention of ZIKV and dengue vims (DENV) infections in a human subject.

A flavivirus Envelope Dimer Epitope (EDE) and isolated neutralizing antibody or antigen binding fragment thereof directed against the EDE for use in vaccinating an individual against one or more flaviviruses wherein the EDE is a stabilized recombinant flavivirus are provided. The dimer is: covalently stabilized with at least one disulphide inter-chain bond or one sulfhydryl-reactive crosslinker between the two sE monomers, and/or by being formed as a single polypeptide chain, and/or by linking the two sE monomers through modified sugar, and/or non-covalently stabilized by substituting at least one amino acid residue in the amino acid sequence of at least one sE monomer with at least one bulky side chain amino acid, at the dimer interface or in domain 1 (D1)/domain 3 (D3) linker of each monomer. The dimer is a homodimer or heterodimer of native and/or mutant envelope polypeptides, from DENV-1, DENV-2, DENV-3, DENV-4, Zika and/or other flavivirus.

Described herein are Zika virus vaccines and compositions and methods of producing and administering said vaccines to subjects in need thereof.

The present invention relates to a lentiviral vector-based Japanese encephalitis (JE) immunogenic composition. The present invention is directed to a recombinant lentiviral vector expressing the precursor of membrane (prM) and the envelope (E) protein, in particular glycoprotein of a Japanese encephalitis virus (JEV) or immunogenic fragments thereof. The present invention also provides cells expressing the lentiviral vector, uses and methods to prevent a JEV infection in a mammalian host, especially in a human or an animal host, in particular a pig or a piglet, preferably a domestic pig or a domestic piglet.

The invention is related to a dengue virus or chimeric dengue virus that contains a mutation in the 3′ untranslated region (3′-UTR) comprising a Δ30 mutation that removes the TL-2 homologous structure in each of the dengue virus serotypes 1, 2, 3, and 4, and nucleotides additional to the Δ30 mutation deleted from the 3′-UTR that removes sequence in the 5′ direction as far as the 5′ boundary of the TL-3 homologous structure in each of the dengue serotypes 1, 2, 3, and 4, or a replacement of the 3′-UTR of a dengue virus of a first serotype with the 3′-UTR of a dengue virus of a second serotype, optionally containing the Δ30 mutation and nucleotides additional to the Δ30 mutation deleted from the 3′-UTR; and immunogenic compositions, methods of inducing an immune response, and methods of producing a dengue virus or chimeric dengue virus.

Described herein are processes for purifying infectious Zika virus particles and uses of protamine in such processes.