Optimization and validation of ELISA immunoassay for the evaluation of in-vitro relative potency of a four-component human papillomavirus vaccine products.

A sandwich-type ELISA was optimized and validated to determine the in-vitro relative potency of the four-component prophylactic Human papillomavirus (HPV) vaccine. The vaccine contains the non-infectious virus like particles (VLP) corresponding to HPV Types 6, 11, 16 and 18. A modification of the desorption step required to release the VLPs from the aluminum adjuvant was carried out. Samples were incubated with citrate buffer for two hours at 37 °C instead of overnight incubation at room temperature. Assay validation was then carried out according to ICH guidelines. The assay was linear over a concentration range of 0.30-2000.00 ng/mL for the four HPV types. The assay was accurate and precise with a LOD of 0.092, 0.081, 0.086 and 0.068 ng/mL for type 6, 11, 16 and 18 respectively. Results were also statistically compared to those obtained using the reported ELISA assay and no significant difference was noted. In contrary to the reported ELISA protocol, this optimized immunoassay was superior with respect to analysis time, without affecting the accuracy and precision (RSD < 5%). This assay has proven to be useful for evaluating the efficacy of the quadrivalent HPV vaccine and is applicable for quality control and batch release purposes.