Flavivirus infections, including dengue virus (DENV), Japanese encephalitis virus (JEV), and Zika virus (ZIKV), present significant global public health challenges. For successful vaccine design, the assessment of neutralizing antibody activity requires reliable and robust methodologies for de-termining antibody titers. Although the plaque reduction neutralization test (PRNT) is commonly acknowledged as the golden standard, it has limitations in terms of time and cost, and the its usage may be limited in resource resource-limited settings. To address these challenges, we introduced the micro-neutralization test (MNT) as a simplified alternative for to the PRNT. The MNT employs a 96-well plate format, conducts microscale neutralization assays, and assesses cell viability by dissolving cells to create a uniform color solution, which is measured with a spectrometer. In this study, we evaluated the utility of the MNT by contrasting the end-point titers of the MNT and PRNT using 4 monoclonal antibodies, 15 non-human primate serum samples, and 2 therapeutic drug candidates across flaviviruses. The results demonstrated a strong correlation between the MNT and PRNT titers, affirming the robustness and reproducibility of the MNT for evaluating control measures against flaviviruses. This research contributes valuable insights towards the development of a cost-effective antibody titer testing approach that is, particularly suitable for resource-limited settings.

Reference:
Haga K. et al., Utility of an In-Vitro Micro-Neutralizing Test in Comparison to a Plaque Reduction Neutralization Test for Dengue Virus, Japanese Encephalitis Virus, and Zika Virus Serology and Drug Screening, Pathogens 2024, 13(1), 8; https://doi.org/10.3390/pathogens13010008
Research paper

Study:
● Department of Developmental Medical Sciences, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
● Department of Biology, Emory College of Art and Science, Emory University, Atlanta, USA

Funding:
Japan Agency for Medical Research and Development (AMED) under grants JP233fa627001, JP22fk0108123 and 23wm0225033h0001.