Detection of Antibodies to AAVs Using Gyrolab® System

EBF Open Symposium 2022 -- Adeno-associated viruses (AAVs) are one of most popular and promising tools for gene therapy with several products already approved for treatment of human genetic diseases. Due to natural infection, pre-existing anti-AAV antibodies widely exist in humans and many animal models. This poses hurdles to the AAV-based gene therapy. An anti-AAV antibody assay is needed to screen cynomolgus monkey colonies for selection of negative or low-responding animals in a toxicology study to maximize the likelihood of successful AAV transduction. Cell-based neutralizing antibody (NAb) assays for transduction inhibition (TI) suffer from variability, matrix interference and non-specificity. Ligand binding assays are more robust and titers of anti-AAV IgG total antibodies (TAb) correlate to those of AAV NAb. Gyrolab® immunoassay platform was selected for its advantages of automation, flexible assay design and low sample/reagent consumption. An anti-AAV2 bridging assay was developed followed by a generic anti-AAV assay where high assay background was encountered and overcome.