The live attenuated yellow fever (YF) vaccine is a highly effective human vaccine and induces long-term protective neutralizing antibodies directed against the viral envelope protein E. The generation of such antibodies requires the help of CD4 T cells which recognize peptides derived from proteins in virus particles internalized and processed by E-specific B cells.
To investigate biological effects of recombination between a chimeric yellow fever (YF) 17D/Japanese encephalitis (JE) vaccine virus (ChimeriVax-JE) and a wild-type flavivirus Kunjin (KUN-cDNA), the prM-E envelope protein genes were swapped between the two viruses, resulting in new YF 17D/KUN(prM-E) and KUN/JE(prM-E) chimeras.
A single amino acid substitution in the envelope protein of chimeric yellow fever-dengue 1 vaccine virus reduces neurovirulence for suckling mice and viremia/viscerotropism for monkeys.