Ackermann-Gäumann et al.
A reporter virus particle seroneutralization assay for tick-borne encephalitis virus overcomes ELISA limitations. J Med Virol. 2024;96(8):e29843. doi:10.1002/jmv.29843
TBE is usually diagnosed by serological assays, mostly by enzyme-linked immunosorbent assay (ELISA). However, cross-reactivities with other flaviviruses may result in false-positive test results. This imponderability can be overcome by using a neutralization assay. It should be noted, however, that such an assay is labor-intensive, time-consuming, and involves the handling of infectious viruses (biosafety level BSL3).
A reporter virus particles (RVP)-based serum neutralization assay (SNT) in which infectivity is measured by luminescence has been developed and which can be handled under BSL2 conditions. This RVP SNT protocol can be applied not only to TBE virus, but uniformly to all RVPs of flaviviruses (e.g. YFV, ZIKV, DENV, WNV, JEV).
In total, 56 serum samples that had been tested by ELISA for specific IgG and IgM antibodies against TBE virus were analyzed using RVP- and virus-based SNT assays. It was found that 53 of 56 samples (94.6%) yielded concordant results when tested using RVP or virus-based SNT methods.
The RVP-based SNT for TBE virus exhibited a highly significant correlation with the commonly used virus-based SNT, demonstrating a sensitivity of 92.3% and a specificity of 100%. All serum samples that had been tested TBE virus-positive by ELISA, but negative in the RVP-based assay, had antibodies to other orthoflaviviruses (YFV, DENV type 2, ZIKV, WNV, JEV).
The authors concluded that the RVP-based SNT assay provides added value in clinical diagnostics as well as in epidemiological studies.