A novel electrophoretic immunoblot as antigen desorption and quantification method for alum-adjuvanted veterinary rabies vaccines

A chemiluminescence immunoassay for precise automatic quality control of glycoprotein in human rabies vaccine

Currently, quality control of glycoprotein in the human rabies vaccine is based on enzyme-linked immunosorbent assay (ELISA). However, ELISA does not match the needs of a modernised quality control system. For a long time, human rabies virus vaccine manufacturers have been devoted to seeking a detection platform that is sensitive, accurate, automatic, and feasible for practical applications. Therefore, our team invested major efforts into establishing a fully automated micromagnetic particle (MMP)-based chemiluminescence immunoassay (CLIA) platform. For vaccine quality control, MMP-coupled rabies virus glycoprotein monoclonal antibodies (S037) were used to capture the rabies virus. Another rabies virus glycoprotein antibody (S053) labelled with acridinium ester was added as a signal tracer. After pretreating the vaccine sample, the entire analysis was performed using a fully automated machine, which had a limited detection time (only 30 min) and eliminated manual error. Multiple experiments have identified the optimal conditions allowing valid and reliable assessment of vaccine potency. The CLIA platform has exhibited merits in terms of speed, robustness, high sensitivity (with a minimum detection value of 0.45 mIU/mL), considerable accuracy, and a wide linear range of detection (9.4-1200 mIU/mL). Furthermore, the results showed that the CLIA platform is consistent with the National Institutes of Health test and time-resolved fluorescent immunoassay (TRFIA) in quantitative analysis, and had a better analytic performance than TRFIA. Therefore, the CLIA platform presented here may be important for application in modern vaccine quality control.

Overcoming scientific barriers in the transition from in vivo to non-animal batch testing of human and veterinary vaccines

INTRODUCTION

Before release, vaccine batches are assessed for quality to evaluate whether they meet the product specifications. Vaccine batch tests, in particular of inactivated and toxoid vaccines, still largely rely on in vivo methods. Improved vaccine production processes, ethical concerns, and suboptimal performance of some in vivo tests have led to the development of in vitro alternatives.

AREAS COVERED

This review describes the scientific constraints that need to be overcome for replacement of in vivo batch tests, as well as potential solutions. Topics include the critical quality attributes of vaccines that require testing, the use of cell-based assays to mimic aspects of in vivo vaccine-induced immune responses, how difficulties with testing adjuvanted vaccines in vitro can be overcome, the use of altered batches to validate new in vitro test methods, and how cooperation between different stakeholders is key to moving the transition forward.

EXPERT OPINION

For safety testing, many in vitro alternatives are already available or at an advanced level of development. For potency testing, in vitro alternatives largely comprise immunochemical methods that assess several, but not all critical vaccine properties. One-to-one replacement by in vitro alternatives is not always possible and a combination of methods may be required.