Live-Attenuated Yellow Fever Virus Strain Adapted to Grow on Vero Cells and Vaccine Composition Comprising the Same
AssigneeSanofi Pasteur Limited
InventorsManuel Vangelisti, Nathalie Mantel, Yves Girerd-Chambaz, Fabienne Piras
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Abstract
The invention relates to a live-attenuated yellow fever virus strain adapted to grow on Vero cells from a parent yellow fever virus 17D substrain that is not adapted to grow on Vero cells, wherein said live-attenuated yellow fever virus strain is less neurovirulent than said parent yellow fever virus 17D substrain.
Claims31
1-25. (canceled)
A live-attenuated yellow fever virus strain comprising a nucleic acid comprising a mutation in the codon for the amino acid at position 480 of an envelope protein (E) which results in an amino acid change from valine to leucine.
A live-attenuated yellow fever virus strain which comprises an envelope protein comprising a leucine residue at the position within the protein that corresponds to position 480 of SEQ ID NO. 15.
A method for obtaining a live-attenuated yellow fever virus strain adapted to grow on Vero cells, the method comprising the steps of:
- a) purifying viral genomic RNA from a parent live-attenuated yellow fever virus strain that is not adapted to grow on Vero cells;
- b) transfecting first Vero cells with the purified viral genomic RNA purified;
- c) growing the transfected first Vero cells in a culture medium, whereby a first population of yellow fever virus is obtained and recovered;
- d) amplifying the recovered first population of yellow fever virus two or more times on second Vero cells, whereby a second population of yellow fever virus is obtained;
- e) cloning the second population of yellow fever virus by two or more successive plaque purifications on third Vero cells, whereby a plurality of yellow fever virus clones is obtained;
- f) individually amplifying each of the recovered yellow fever virus clones two or more times on fourth Vero cells, whereby a plurality of yellow fever virus strains is obtained and recovered;
- and
- g) selecting from the recovered plurality of yellow fever virus strains one or more live-attenuated yellow fever virus strain that is less neurovirulent than the parent live-attenuated yellow fever virus strain, in a mouse lethal dose 50 (MLD50) test.
Dependencies are inferred from the claim text.