2017 ACVIM Forum Research Abstract Program

Serum samples from seven pet dogs and seven pet cats with varying levels of circulating anti-AAV8 and anti-AAV9 antibodies were utilized. Neutralizing antibody assays were performed using a Self-complementary c-smCBA-mCherry reporter packaged in either AAV8 or AAV9 and permissive cells (661W and Lec2, respectively) at a multiplicity of infection of 10,000 vg/cell. Positive controls were serum samples from dogs in a research colony that had been previously treated with AAV8 and AAV9 vectors and negative controls had no serum. Vectors were pre-incubated with series of serum dilutions (1:10, 1:40, 1:160, 1:640 and 1:2560) before infecting cells. Three days post infection, transduction was assessed by measuring mCherry-mediated fluorescence. Neutralization of transduction greater than 50% relative to no serum control in the lowest dilution (1:10) was identified in 2/7 cats and 1/7 dogs for AAV8 and 1/7 cats and 5/7 dogs for AAV9. There was no obvious positive correlation between circulating antibody titers and neutralization titers. There was a trend for the presence of feline serum to have a positive impact on transduction efficiency of both vectors.