Designing of Immuno-capture ELISA assay kit for rabies vaccine potency

Background: Potency evaluation of rabies vaccine is a cheap, fast, high precision and consistent with ethical values is critical, so researchers have modified a variety of methods such as: National Institute of Health (NIH) method, Single Radial Immunodiffusion (SRID) and so on. The purpose of the present study was to replace an in vitro method consistent with medical ethics criteria instead of an in vivo method. By recognizing that the potency of the rabies vaccine depends on the amount of glycoprotein antigen content and the monoclonal antibody detect the correct folding of antigen of the rabies virus, then the glycoprotein content could be represent of vaccine potency. Methods: In this study, we designed an immune-capture enzyme-linked immunosorbent assay (ELISA) with three antibodies (capture, primary and secondary) to determine the existent amount of viral glycoprotein in different rabies vaccines, and compared the results at the same time with measuring potency of those vaccines using the NIH method. This applied study was conducted from September 2016 to September 2018 at the Research Laboratory of the World Health Organization Collaborating Center for reference and research on rabies at the Pasteur Institute of Iran in Tehran. Results: The slope of the standard line was calculated to R2=0.98 (P=0.0013). In the humans’ vaccines, the mean lied between 5.554-7.336 (SD=0.0463-0.1039) and the coefficient of variation was 0.778-2.436 (SD=0.0041-0.2724), at the same time in the animals’ vaccines the mean were 2.293-5.993 (SD=0.0041-0.2724) and the coefficient of variation was calculated 0.182-4.546. For animal vaccines the Pearson correlation coefficient is 0.99 and for the human vaccines this coefficient was 0.95. Also, the concordance correlation coefficient for animal vaccines was 0.98 and for human vaccines is 0.95, indicating a moderate to high concordance in both animals and humans vaccines. Conclusion: The designed Immuno-capture ELISA kit had a proper acceptance criterion, intermediate precision, good linearity and robustness for measuring the glycoprotein level of the vaccine, which was directly related to the vaccine potency.