The present disclosure provides compositions and methods for use in vaccines, comprising polynucleotides encoding one or more viral antigen proteins and an enhancer protein, wherein the enhancer protein is a picornavirus leader (L) or a functional variant thereof. The compositions and methods provided herein may improve the production of functional viral-like particles (VLP).

The instant invention discloses a closed-system, serum-free, microcarrier-based up-stream process to produce dengue virus. The process comprises a closed-system cell expansion comprising cell passages taking place in closed-system containers. These cell expansions represent a closed process, with replacement media, a cell-detachment agent, and quench medium added though sterile, weldable tubing (a closed-system environment) to eliminate all open aseptic processing following the initial vial thaw of the adherent cells. The viral production takes place in a closed-system bioreactor in adherent cell culture grown on microcarriers providing sufficient cell mass to support the production of dengue virus.

A group of mosquito-borne flaviviruses that cause fatal encephalitis in humans is among the most important of all emerging human pathogens of global significance. This group includes Japanese encephalitis virus (JEV), West Nile virus, St. Louis encephalitis virus, and Murray Valley encephalitis virus. In the present disclosure, the first reverse genetics system has been developed for SA14-14-2, a live JE vaccine that is most commonly used in most JE-endemic areas, by constructing an infectious bacterial artificial chromosome that contains the full-length SA14-14-2 cDNA. Using this infectious SA 14-14-2 cDNA, combined with a mouse model for JEV infection, a key viral neurovirulence factor has been discovered that is a conserved single amino acid in the ij hairpin adjacent to the fusion loop of the viral E glycoprotein, which regulates viral infectivity into neurons within the central nervous system.

The present invention provides methods for large-scale flaviviral vaccine production and manufacture. The methods provided herein are specifically contemplated for large-scale production and manufacture of live, attenuated flaviviral vaccines such as live, attenuated, dengue virus vaccines. Further, the methods provided herein pertain to formulation of live, attenuated, monovalent, divalent, trivalent, or tetravalent viral vaccine products.

A group of mosquito-borne flaviviruses that cause fatal encephalitis in humans is among the most important of all emerging human pathogens of global significance. This group includes Japanese encephalitis virus (JEV), West Nile virus, St. Louis encephalitis virus, and Murray Valley encephalitis virus. In the present disclosure, the first reverse genetics system has been developed for SA14-14-2, a live JE vaccine that is most commonly used in most JE-endemic areas, by constructing an infectious bacterial artificial chromosome that contains the full-length SA14-14-2 cDNA. Using this infectious SA 14-14-2 cDNA, combined with a mouse model for JEV infection, a key viral neurovirulence factor has been discovered that is a conserved single amino acid in the ij hairpin adjacent to the fusion loop of the viral E glycoprotein, which regulates viral infectivity into neurons within the central nervous system.

The present invention aims to provide a method for testing the function of antibodies that uses safe antigens and gives results more quickly. The present invention relates to a method for determining antibody-dependent enhancement ability of antibodies, including contacting, in the presence of a test antibody, Fc receptor-expressing cell with single round infectious virus particles containing a gene with a region encoding a labeled protein and a region encoding non-structural (NS) proteins 1 to 5 of the yellow fever virus genome, a capsid protein of a virus, and an outer shell protein (Envelope) of a virus, wherein when the measured label is greater than that of a negative control cell, the test antibody is determined to have an antibody-dependent enhancement ability, and the like.

Embodiments herein concern compositions, methods, and uses for inducing an immune response to all four dengue virus serotypes in a child or young adult from about 1 year to about 20 years of age. Some embodiments concern compositions that can include, but are not limited to, dengue virus chimeras that, either alone or in combination with other constructs, can be used in a vaccine composition against all four dengue virus serotypes. In certain embodiments, compositions can include constructs of more than one serotypes of dengue virus, such as dengue-1 (DEN-1) virus, dengue-2 (DEN-2) virus, dengue-3 (DEN-3) virus and/or dengue-4 (DEN-4) virus, at various concentrations or ratios in order to improve protection from infection in children and young adults. In certain embodiments, viruses of the formulations are limited to dengue virus serotypes. Other embodiments concern methods of administering immunogenic compositions against dengue virus that can include chimeric dengue constructs and live, attenuated dengue viruses using single, dual or other regimens.

The present disclosure relates to sVERO 7C2, which is a Vero cell line derived from Vero cells (African Green Monkey Kidney Cell Line) distributed from the WHO and capable of suspension culture without serum components. Further, the present disclosure relates to a culture method for growing the Vero cells and a method for producing a vaccine virus using the Vero cells.