Comparison of four serological tests for detecting antibodies to Japanese encephalitis virus after vaccination in children.
OBJECTIVE
Several different methods are currently used to detect antibodies to Japanese encephalitis virus (JEV) in serum samples or cerebrospinal fluid. These methods include the plaque reduction neutralization test (PRNT), the hemagglutination inhibition (HI) test, indirect immunofluorescence assay (IFA), and enzyme-linked immunosorbent assay (ELISA). The purpose of this study was to compare the performance of each method in detecting vaccine-induced antibodies to JEV.


METHODS
The study included 29 children who had completed a primary immunization schedule with an inactivated vaccine against JEV derived from mouse brain (n = 15) or a live attenuated SA14-14-2 vaccine (n = 14). Serum samples were collected between 3 months and 47 months after the last immunization. The serum samples were tested by performing the PRNT, HI test, in-house IFA, and commercial ELISA. The antibody detection rates were compared between tests.


RESULTS
All 29 serum samples were positive with the PRNT, showing antibody titers from 1:20 to 1:2560. The HI test showed positive rates of 86.7% (13/15) and 71.4% (10/14) in the inactivated and live attenuated vaccine groups, respectively. The results of the IFA for immunoglobulin (Ig)G were positive in 53.3% (8/15) of children in the inactivated vaccine group and 35.7% (5/14) in the live attenuated vaccine group. Neither the IFA nor ELISA detected JEV IgM antibodies in any of the 29 children.


CONCLUSIONS
These results show that detection rates of vaccine-induced antibodies to JEV have a wide range (0-100%) depending on the testing method as well as the time since immunization and individual differences between children. These findings are helpful in interpreting serological test results for the diagnosis of Japanese encephalitis in situations where vaccines are widely administered.
WHO/WPRO Japanese Encephalitis Regional Refernce Laboratory, 187 Osongsaengmyeong2-ro, Chungbuk 363-951, Korea ; Division of Arboviruses, National Institute of Health, Korea Centers for Disease Control and Prevention, 187 Osongsaengmyeong2-ro, Chungbuk 363-951, Korea.
Go Woon
GW
Cha
WHO/WPRO Japanese Encephalitis Regional Refernce Laboratory, 187 Osongsaengmyeong2-ro, Chungbuk 363-951, Korea ; Division of Arboviruses, National Institute of Health, Korea Centers for Disease Control and Prevention, 187 Osongsaengmyeong2-ro, Chungbuk 363-951, Korea.
Jung Eun
JE
Cho
WHO/WPRO Japanese Encephalitis Regional Refernce Laboratory, 187 Osongsaengmyeong2-ro, Chungbuk 363-951, Korea ; Division of Arboviruses, National Institute of Health, Korea Centers for Disease Control and Prevention, 187 Osongsaengmyeong2-ro, Chungbuk 363-951, Korea.
Young Ran
YR
Ju
Department of Pediatrics, Inha University Medical School, Incheon, Korea.
Young-Jin
YJ
Hong
WHO/WPRO Japanese Encephalitis Regional Refernce Laboratory, 187 Osongsaengmyeong2-ro, Chungbuk 363-951, Korea ; Division of Arboviruses, National Institute of Health, Korea Centers for Disease Control and Prevention, 187 Osongsaengmyeong2-ro, Chungbuk 363-951, Korea.
Myung Guk
MG
Han
WHO/WPRO Japanese Encephalitis Regional Refernce Laboratory, 187 Osongsaengmyeong2-ro, Chungbuk 363-951, Korea ; Division of Arboviruses, National Institute of Health, Korea Centers for Disease Control and Prevention, 187 Osongsaengmyeong2-ro, Chungbuk 363-951, Korea.
Won-Ja
WJ
Lee
Department of Biomedical Sciences, Hallym University, Chuncheon, Korea.
Eui Yul
EY
Choi
WHO/WPRO Japanese Encephalitis Regional Refernce Laboratory, 187 Osongsaengmyeong2-ro, Chungbuk 363-951, Korea ; Division of Arboviruses, National Institute of Health, Korea Centers for Disease Control and Prevention, 187 Osongsaengmyeong2-ro, Chungbuk 363-951, Korea ; Department of Biomedical Sciences, Hallym University, Chuncheon, Korea.
Young Eui
YE
Jeong
Japanese encephalitis; enzyme-linked immunosorbent assay; hemagglutination inhibition; indirect immunofluorescence assay; plaque reduction neutralization test