Chimera Vaccine Evaluated.(Brief Article)

2001 FEB 21 - (NewsRx.com & NewsRx.net) --

by Michelle Marble, staff medical writer -- Researchers in the United States evaluated different vaccine strains to find the best candidate to provide protection against Japanese encephalitis.

"A yellow fever virus (YFV)/Japanese encephalitis virus (JEV) chimera in which the structural proteins prM and E of YFV 17D are replaced with those of the JEV SA14-14-2 vaccine strain is under evaluation as a candidate vaccine against Japanese encephalitis," wrotes J. Arroyo and colleagues, St. Louis University, Missouri. "The chimera (YFV/JEV SA14-14-2, or ChimeriVax-JE) is less neurovirulent than is YFV 17D vaccine in mouse and nonhuman primate models."

Arroyo et al. published their study in the Journal of Virology ("Molecular basis for attenuation of neurovirulence of a yellow fever virus/Japanese encephalitis virus chimera vaccine (ChimeriVax-JE)," J Virol, January 2001;75(2):934-942).

"Attenuation depends on the presence of the JEV SA14-14-2 E protein, as shown by the high neurovirulence of an analogous YFV/JEV Nakayama chimera derived from the wild JEV Nakayama strain," the authors said.

There are 10 amino acid differences between the E proteins of ChimeriVax-JE and the YFV/JEV Nakayama virus. Four of these amino acid differences are predicted to be neurovirulence determinants. The investigators determined this based on various sequence comparisons.

To identify residues that could be involved in attenuation, the researchers engineered and tested a series of intratypic YFV/JEV chimeras containing either single or multiple amino acid substitutions in a murine model for ...