Attached
Japanese encephalitis (lE) is one of the major viral
diseases in Asian countries, and there are more
than 70,000 .IE cases reported annually. JE virus
(lEV) belongs to the same family as the dengue
virus and they both coexist geographically. Because
of the cross reactivity between these two "Viruses,
the detection of a past JEV infection has been
difficult in a background of immunity to dengue
virus. The currently available diagnostic kits for
JEV show cross reactivity towards antibodies
against dengue virus. The current study, therefore,
aimed to develop an assay for the detection of preexisting immunity specifically against JEV in a
background of immunity to dengue. Bioinformatic
analyses was conducted to identify short peptides
from JEV proteins, which ai .. e conserved in JEV.
Thirty six peptides are highly unique to JEV. TIle
synthesis of 22 of the 36 peptides were successful
in commercial synthesis and they were subjected to
~ ;ENERAL)lR JOH\ KCTELAWALA DE:E,CE UfJlVERSITY I lOin INTERNATIONAL RESEARCH CONFERENCE
Enzyme Linked ImmunoSorbent Assay (ELISA),
to identify peptides that respond to antibodies
generated specifically against JEV. Sera were
collected from healthy volunteers who have been
JE vaccinated and non-vaccinated, with or without
a past dengue infection. Seven of these peptides
g-ave responses only to sera of individuals who had
been vaccinated with JE and there were no antibody
responses to sera of those who had not been
vaccinated for JE but had past dengue infection.
When those 7 peptides were assayed together as a
pool, the specificity and sensitivity of detecting 001
individual with pre-existing immunity Wa!5 100%
and 85% respectively. Therefore, those peptides
can be utilized as a marker for the diagnosis of aJEV
infection in the background of dengue infection.
