The chimeric virus was created by replacing the pre-membrane and
envelope proteins from Yellow fever virus strain 17D (YFV)
with the corresponding sequences from Japanese encephalitis
virus (JEV) strain SA14-14-2. Since, the viral genome is
single stranded, positive RNA, cDNA was synthesized to replace the
genes in the viral genome. After creating the chimeric genome, RNA
was synthesized from the cDNA and injected into host cells to
create chimeric viral particles.
Translation begins from the 5' noncoding region, synthesizing a
single, polyprotein before terminating at the 3' noncoding region.
Upon translation, nonstructural protein 3 along with nonstructural
protein 2B autocatalyze peptide cleavage. The final viral particles
contain YFV anchored protein C (ancC), YFV protein C (processed
from ancC), JEV pre-membrane protein (prM), JEV protein M
(processed from prM), JEV envelope protein, and viral RNA.
The chimeric virus was created from live, attenuated YFV and JEV
vaccine strains and demonstrated a similar lack of virulence of the
parental strains. However, the immune response was sufficient to
create immunity to wild-type JEV.