title: Minimizing the inhibitory effect of neutralizing antibody for efficient gene expression in the liver with adeno-associated virus 8 vectors.
abstract: Neutralizing antibodies (NAbs) against adeno-associated viruses (AAVs) are known to interfere with AAV vector-mediated gene transfer by intravascular delivery. Evading the inhibitory effects of antibodies against AAV vectors is necessary for efficient transfer of therapeutic genes clinically. For this purpose, we tested the efficacy of saline flushing in order to avoid contact of vectors with NAbs present in blood. Direct injection of the AAV8 vector carrying the factor IX (FIX) gene into the portal vein of macaques using saline flushing achieved transgene-derived FIX expression (4.7 ± 2.10-10.1 ± 5.45% of normal human FIX concentration) in the presence of NAbs. Expression was as efficient as that (5.43 ± 2.59-12.68 ± 4.83%) in macaques lacking NAbs. We next tested the efficacy of saline flushing using less invasive balloon catheter-guided injection. This approach also resulted in efficient expression of transgene-derived FIX (2.5 ± 1.06-9.0 ± 2.37%) in the presence of NAbs (14-56× dilutions). NAbs at this range of titers reduced the efficiency of transduction in the macaque liver by 100-fold when the same vector was injected into mesenteric veins without balloon catheters. Our results suggest that portal vein-directed vector delivery strategies with flushing to remove blood are efficacious for minimizing the inhibitory effect of anti-AAV antibodies.
authors.affiliation: Division of Cell and Molecular Medicine, Center for Molecular Medicine, Jichi Medical University, Tochigi-ken, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Mimuro
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Mizukami
authors.forename: Shuji
authors.initials: S
authors.lastname: Hishikawa
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Ikemoto
authors.forename: Akira
authors.initials: A
authors.lastname: Ishiwata
authors.forename: Asuka
authors.initials: A
authors.lastname: Sakata
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Ohmori
authors.forename: Seiji
authors.initials: S
authors.lastname: Madoiwa
authors.forename: Fumiko
authors.initials: F
authors.lastname: Ono
authors.forename: Keiya
authors.initials: K
authors.lastname: Ozawa
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Sakata
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000276:immunology*; D057785:Catheters; D000229:Dependovirus / Q000235:genetics / Q000276:immunology*; D005164:Factor IX / Q000235:genetics; D015870:Gene Expression; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D005822:Genetic Vectors; D006801:Humans; D008099:Liver / Q000378:metabolism*; D008251:Macaca; D020125:Mutation, Missense; D011169:Portal Vein; D019076:Transgenes
chemical_list: D057134:Antibodies, Neutralizing; D005164:Factor IX