title: Optimized transduction of human monocyte-derived dendritic cells by recombinant adeno-associated virus serotype 6.
abstract: Dendritic cells are the key antigen-presenting cells involved in the initiation of the adaptive immune response. Recombinant adeno-associated viruses (rAAVs) can transduce dendritic cells and have gained attention as potential vaccines capable of stimulating T cell immunity. Here we show that rAAV2 pseudotyped with type 6 capsid (rAAV2/6) exhibits significantly higher tropism for human monocyte-derived dendritic cells (MoDCs) than other serotypes and variants. Transduction was abolished by a single lysine-to-alanine mutation within the AAV6 capsid previously shown to inhibit binding to heparin. However, unlike rAAV2, soluble heparin did not inhibit rAAV2/6 transduction of MoDCs. Further enhancement of MoDC transduction was observed after mutation of Tyr-731 in the capsid of AAV6 consistent with a report that tyrosine residues are phosphorylated, leading to ubiquitination of capsids during uptake. Pseudotyped rAAV2/6 vectors containing a Y731F mutation minimally altered the immunophenotype of MoDCs, which retained their immunostimulatory ability and were able to stimulate an antigen-specific CD8(+) T cell clone. These findings should assist in the development of rAAV2/6 as a vaccine vector.
authors.affiliation: University of Auckland, New Zealand.
authors.forename: James E
authors.initials: JE
authors.lastname: Ussher
authors.forename: John A
authors.initials: JA
authors.lastname: Taylor
mesh_terms: D000595:Amino Acid Sequence; D036022:Capsid Proteins / Q000235:genetics; D002454:Cell Differentiation; D003713:Dendritic Cells / Q000378:metabolism* / Q000821:virology; D000229:Dependovirus / Q000235:genetics*; D049452:Green Fluorescent Proteins / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D016130:Immunophenotyping; D008969:Molecular Sequence Data; D009000:Monocytes / Q000166:cytology*; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D011994:Recombinant Proteins / Q000096:biosynthesis* / Q000235:genetics; D016415:Sequence Alignment; D012703:Serotyping; D014161:Transduction, Genetic; D019562:Viral Load; D056189:Viral Tropism
chemical_list: D036022:Capsid Proteins; D011994:Recombinant Proteins; D049452:Green Fluorescent Proteins