During development of a
subunit vaccine, monitoring integrity of the
recombinant protein for process development and quality control is critical. Pfs230 is a leading
malaria transmission blocking
vaccine candidate and the first to reach a Phase 2 clinical trial. The Pfs230
protein is expressed on the surface of gametes, and plays an important role in male fertility. While the potency of Pfs230
protein can be determined by a standard membrane-feeding assay (SMFA) using
antibodies from immunized subjects, the precision of a general in vivo potency study is known to be poor and is also time-consuming. Therefore, using a well-characterized Pfs230
recombinant protein and two human anti-Pfs230
monoclonal antibodies (mAbs), which have functional activity judged by SMFA, a sandwich ELISA-based in vitro potency assay, called the
Antigen Integrity Assay (AIA), was developed. Multiple validation parameters of AIA were evaluated to qualify the assay following International Conference on Harmonization (ICH) Q2(R1) guidelines. The AIA is a high throughput assay and demonstrated excellent precision (3.2 and 5.4% coefficients of variance for intra- and inter-assay variability, respectively) and high sensitivity (>12% impurity in a sample can be detected). General methodologies and the approach to assay validation described herein are amenable to any
subunit vaccine as long as more than two functional, non-competing mAbs are available. Thus, this study supports future
subunit vaccine development.