High-throughput assay for detection of rabies neutralizing antibodies

According to 2010-2014 World Health Organization (WHO) research, dog-transmitted human rabies was present or suspected in 150 countries and territories worldwide. Domestic dogs were the most common reservoir of the rabies virus in these countries, and more than 99% of human deaths were caused by dog-transmitted rabies. Rabies is 100% preventable in dogs with appropriate administration of vaccines.

Virus neutralization assays are essential for assessing vaccine efficacy. Current methods to detect rabies-specific neutralizing antibodies involve skilled personnel using a traditional 8-well slide and manually reading a microscope after staining rabies virus (RABV)-infected cells with fluorescently-labelled antibodies. Results are qualitative, time-consuming, labor-intensive, and low throughput. Additionally, images cannot be stored for future analysis.

To address these current limitations, CDC researchers developed high-throughput neutralization assays across two testing platforms using a recombinant RABV expressing green fluorescent protein (GFP) that can assess the presence of neutralizing antibodies in serum. Presence of neutralizing antibodies can then be detected using high-throughput flow cytometry, or automated microscopy and image analysis. Both methods provide unbiased and quantitative values of RABV-infected cells to determine anti-rabies neutralizing antibody titers in test samples.