Evaluation of Chimeric Japanese Encephalitis and Dengue Viruses for Use in Diagnostic Plaque Reduction Neutralization Tests

Abstract

The plaque reduction neutralization test (PRNT) is a specific serological test used to identify and confirm arbovirus infection in diagnostic laboratories and monitor immunological protection in vaccine recipients. Wild-type (wt) viruses used in the PRNT may be difficult to grow and plaque titrate, such as the dengue viruses (DENV), and/or may require biosafety level 3 (BSL3) containment, such as West Nile virus (WNV), St. Louis encephalitis virus (SLEV), and Japanese encephalitis virus (JEV). These requirements preclude their use in diagnostic laboratories with only BSL2 capacity. In addition, wt JEV falls under the jurisdiction of the select-agent program and can be used only in approved laboratories. The chimeric vaccine viruses ChimeriVax-WNV and -SLEV have previously been shown to elicit antibody reactivity comparable to that of parental wt WNV and SLEV. ChimeriVax viruses provide advantages for PRNT, as follows: they grow more rapidly than most wt flaviviruses, produce large plaques, require BSL2 conditions, and are not under select-agent restrictions. We evaluated the ChimeriVax-DENV serotype 1 (DENV1), -DENV2, -DENV3, -DENV4, and -JEV for use in PRNT on sera from DENV-and JEV-infected patients and from JEV vaccine recipients. Serostatus agreement was 100% between the ChimeriVax-DENV serotypes and wt prototype DENV and 97% overall with ChimeriVax-JEV compared to prototype Nakayama JEV, 92% in a subgroup of JEV vaccine recipients, and 100% in serum from encephalitis patients naturally infected with JEV. ChimeriVax-DENV and -JEV plaque phenotype and BSL2 requirements, combined with sensitive and specific reactivity, make them good substitutes for wt DENV and JEV in PRNT in public health diagnostic laboratories.

A Randomized, Double-Blind, Controlled Trial of the 17D Yellow Fever Virus Vaccine Given in Combination with Immune Globulin or Placebo: Comparative Viremia and Immunogenicity

“….). 22 Undetected PRNT 90 titers were set to five (i.e., log 2 [PRNT/10] = −1). This transformation ensured that the titers met the asymptotic normal properties required by general linear models.…”

Endogenous feline retrovirus RD-114 does not elicit neutralizing antibodies in dogs

“…If neutralizing antibodies were shown to increase in the virus group as opposed to the inactivated virus group, this would suggest that neutralizing antibodies were induced as a result of virus propagation. Immunoglobulin M is produced early during infection, is detectable within a few days from the onset of the illness and is more virus-specific than immunoglobulin G (10). Our data related to the globulin levels suggest that a significant antibody response did not occur in inoculated dogs.…”

Evaluation of IgM Antibody Capture Enzyme-Linked Immunosorbent Assay Kits for Detection of IgM against Japanese Encephalitis Virus in Cerebrospinal Fluid Samples

“…19,20 Each sample was tested simultaneously with challenge viruses ChimeriVax™-JEV and ChimeriVax™-DENV2 (Sanofi-Pasteur, Lyon, France [formerly Acambis Inc., Cambridge, MA]). [21][22][23][24] The DENV2 New Guinea C (NGC) strain is the prototype virus used in the DENV2 PRNT and the parental virus to Chimerivax™-DENV2. In clinical specimens from patients infected with other DENV serotypes, there is detect able antibody cross-reactivity to DENV2 NGC and ChimeriVax™-DENV2 sufficient for initial PRNT screening (Kosoy O, CDC, unpublished data).…”