Viral Vector Capsid Titer Interlab Study (RFA2025.03)

NIIMBL is pleased to announce this Request for Application (RFA) to participate in the Viral Vector Program interlab study to evaluate whether utilizing the new United States Pharmacopeia (USP) AAV9 Reference material as a calibrant can improve the accuracy and precision of AAV9 capsid titer measurements from commercial Enzyme-Linked Immunosorbent Assay (ELISA) kits.  

ELISA is the most common technique to measure capsid titer. However, the variability between commercial ELISA kits and calibrants introduces uncertainty in the accuracy and precision of reported capsid titers. This RFA aims to address this variability by evaluating a new AAV9 analytical reference material developed by the United States Pharmacopeia (USP, catalog #1800241), which can be used as an ELISA calibrant.  

Study Goals

• Compare the accuracy and precision of AAV9 capsid titer measurements across multiple commercial ELISA kits when the standard curve is comprised of (1) the USP calibrant vs. (2) the kit-included standard.
• Compare intra- and inter-laboratory variability using the USP calibrant vs. existing ELISA kit standards.
• Support regulatory alignment and qualification of the USP calibrant for broader industry use.

The application deadline is Tuesday, November 18, 2025.