title: Circulating anti-wild-type adeno-associated virus type 2 (AAV2) antibodies inhibit recombinant AAV2 (rAAV2)-mediated, but not rAAV5-mediated, gene transfer in the brain.
abstract: Epidemiological studies report that 80% of the population maintains antibodies (Ab) to wild-type (wt) adeno-associated virus type 2 (AAV2), with 30% expressing neutralizing Ab (NAb). The blood-brain barrier (BBB) provides limited immune privilege to brain parenchyma, and the immune response to recombinant AAV (rAAV) administration in the brain of a naive animal is minimal. However, central nervous system transduction in preimmunized animals remains unstudied. Vector administration may disrupt the BBB sufficiently to promote an immune response in a previously immunized animal. We tested the hypothesis that intracerebral rAAV administration and readministration would not be affected by the presence of circulating Ab to wt AAV2. Rats peripherally immunized with live wt AAV2 and naive controls were tested with single intrastriatal injections of rAAV2 encoding human glial cell line-derived neurotrophic factor (GDNF) or green fluorescent protein (GFP). Striatal readministration of rAAV2-GDNF was also tested in preimmunized and naive rats. Finally, serotype specificity of the immunization against wt AAV2 was examined by single injections of rAAV5-GFP. Preimmunization resulted in high levels of circulating NAb and prevented transduction by rAAV2 as assessed by striatal GDNF levels. rAAV2-GFP striatal transduction was also prevented by immunization, while rAAV5-GFP-mediated transduction, as assessed by stereological cell counting, was unaffected. Additionally, inflammatory markers were present in those animals that received repeated administrations of rAAV2, including markers of a cell-mediated immune response and cytotoxic damage. A live virus immunization protocol generated the circulating anti-wt-AAV Ab seen in this experiment, while human titers are commonly acquired via natural infection. Regardless, the data show that the presence of high levels of NAb against wt AAV can reduce rAAV-mediated transduction in the brain and should be accounted for in future experiments utilizing this vector.
authors.affiliation: University of Florida College of Medicine, P.O. Box 100244, Gainesville, FL 32610, USA.
authors.forename: Carmen S
authors.initials: CS
authors.lastname: Peden
authors.forename: Corinna
authors.initials: C
authors.lastname: Burger
authors.forename: Nicholas
authors.initials: N
authors.lastname: Muzyczka
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Mandel
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood* / Q000276:immunology*; D001921:Brain / Q000276:immunology* / Q000821:virology; D003342:Corpus Striatum / Q000276:immunology; D000229:Dependovirus / Q000145:classification / Q000235:genetics / Q000276:immunology*; D005260:Female; D018014:Gene Transfer Techniques; D005822:Genetic Vectors / Q000008:administration & dosage* / Q000276:immunology; D051100:Glial Cell Line-Derived Neurotrophic Factor; D049452:Green Fluorescent Proteins; D007114:Immunization; D007117:Immunization, Secondary; D008164:Luminescent Proteins / Q000235:genetics / Q000276:immunology; D009414:Nerve Growth Factors / Q000235:genetics / Q000276:immunology; D009500:Neutralization Tests; D010322:Parvoviridae Infections / Q000276:immunology / Q000517:prevention & control / Q000821:virology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011995:Recombination, Genetic; D014161:Transduction, Genetic; D019076:Transgenes
chemical_list: D000914:Antibodies, Viral; C495041:Gdnf protein, rat; D051100:Glial Cell Line-Derived Neurotrophic Factor; D008164:Luminescent Proteins; D009414:Nerve Growth Factors; D049452:Green Fluorescent Proteins