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- Title
745. AAV12, Isolated from Vervet Monkey, Has Unique Tropism and Biological as Well as Neutralization Properties.
- Authors
Schmidt, Michael; Voutetakis, Antonis; Afione, Sandra; Changyu Zheng; Chiorini, John A.
- Abstract
As part of an ongoing study to identify and characterize novel AAV isolates, we have screened virus isolates stored at the American Type Culture Collection. In a sample of adenovirus isolated from Vervet monkey (Cercopithecus aethiops) we have identified a new AAV with limited sequence homology to known AAVs and termed it AAV12. The capsid protein of AAV12 demonstrated highest homology with AAV11 and AAV4, 84% and 78% respectively, whereas AAV5 VP1 displayed lowest similarity with 53%. The Rep78 amino acid sequence of AAV12 is 89% identical to AAV4 and AAV11.To initially characterize AAV12, we analyzed the cellular elements that mediate transduction of recombinant virus. All AAVs characterized so far utilize either the glycosaminoglycan (GAG) heparan sulfate or sialic acid as receptor or attachment factor. Competition experiments with GAGs as well as the enzymatic removal of cell surface sialic acid demonstrated that AAV12 does not utilized GAGs or sialic acid as receptor. Involvement of glycolipids in the transduction process was excluded by studies utilizing inhibitors of glycolipid synthesis, whereas inhibition of transduction was observed after proteolytic digest of the cell prior to infection, suggesting that the AAV12 receptor is a protein. To analyze, if the AAV12 receptor complex includes a carbohydrate component, we screened a panel of mono- and oligosaccharides for their potential to compete with AAV12 transduction. Mannose and mannosamine inhibited AAV12 transduction, suggesting that these carbohydrates are part of the AAV12 receptor.The unique virus-cell interaction suggests a unique tropism of AAV12. This was confirmed by transduction experiments with recombinant virus in a broad panel of human cancer cell lines. The utility of AAV12 to mediate gene transfer was analyzed in mouse studies, where rAAV12 mediated gene transfer to salivary glands comparable with rAAV2.A potential limitation of utilizing AAV vectors in clinical studies is a strong pre-existing immunity to AAV in many patients. We therefore assayed A AV12 for neutralization by human immunoglobulin G (IgG) with a pool of intravenous immune globulin from 5000 human subjects (IVIG). rAAV12 was 100 times more resistant in an in vitro assay to neutralization by IVIG than either rAAV2 or rAVV6.The unique biological properties of AAV12, including its low neutralization by human IgGs, suggest that rAAV12 might be utilized as vector for gene therapy applications.Molecular Therapy (2006) 13, S288–S288; doi: 10.1016/j.ymthe.2006.08.827
- Subjects
GENETIC transduction; MICROBIAL genetics; CERCOPITHECUS aethiops; CANCER genetics; CANCER treatment; GENETIC engineering
- Publication
Molecular Therapy, 2006, Vol 13, pS288
- ISSN
1525-0016
- Publication type
Article
- DOI
10.1016/j.ymthe.2006.08.827