ESTABLISHING A PROCEDURE FOR DETERMINING RABIES ANTIBODY TITER USING NEUTRALIZATION METHOD ON BHK21 CELLS

Abstract

The National Institute for Control of Vaccines and Biologicals (NICVB) currently uses the mouse neutralizing antibody test (MNT) to evaluate anti-rabies serum potency, but it has many disadvantages. Since 2018, the World Health Organization (WHO) has recommended alternative methods for determining rabies virus neutralizing antibody titers on BHK-21 cells (FAVN). Hence, this study was conducted to establish a procedure for determining rabies antibody titers using the neutralization method on BHK-21 cells and validate assay based on criteria such as accuracy, repeatability and intermediate precision. This research pointed out that 5 x10⁵ cells per mL is the most optimal concentration of cells. The average titer value of the international anti-rabies standard sample code NIBSC 19/244 is 167.52 IU, with a R% recovery of 102.14% compared to the number indicated on the label, meeting the accuracy requirement. Additionally, the method guarantees repeatability and intermediate precision with a coefficient of variation (CV) less than 20%, which is suitable for evaluating anti-rabies serum in NICVB