In vitro selection of viral vectors with modified tropism: the adeno-associated virus display

Abstract

Improving the efficiency and specificity of gene vectors is critical for the success of gene therapy. In an effort to generate viral mutants with controlled tropism we produced a library of adeno-associated virus (AAV) clones with randomly modified capsids and used it for the selection of receptor-targeting mutants. After several rounds of selection on different cell lines that were resistant to infection by wild-type (wt) AAV, infectious mutants were harvested at high titers. These mutants transduced target cells with an up to 100-fold increased efficiency, in a receptor-specific manner and without interacting with the primary receptor for wt AAV. The results demonstrate for the first time that a combinatorial approach based on a eukaryotic virus library allows one to generate efficient, receptor-specific targeting vectors with desired tropism.

Heart-targeted adeno-associated viral vectors selected by in vivo biopanning of a random viral display peptide library

“…Also, the post-entry events may be determined by yet unknown tissue-specific factors. A major step forward to improve the target peptide design has been the development of virus display peptide libraries [33][34][35][36][37] or libraries of random capsid chimeras derived from different AAV serotypes. [8][9][10] In such libraries, a multitude of potentialtargeting motifs is presented within the restrictions of capsid assembly and genome packaging.…”

Library-based selection of retroviruses selectively spreading through matrix metalloprotease-positive cells

“…Moreover, with the library approach demonstrated here for retroviruses, and recently also for adenoassociated viral vectors, the generation of individualized targeted viruses becomes conceivable if appropriate libraries are selected on a panel of different tumour cell lines or even on patient tumour biopsy material. 23 Tumour therapy can then be started having the best available targeting virus for a given tumour at hand. Beyond that, the linker peptides selected this way will also be of high value for the design of MMP-activatable toxins or cytokines.…”

Engagement of the B-cell antigen receptor (BCR) allows efficient transduction of ZAP-70-positive primary B-CLL cells by recombinant adeno-associated virus (rAAV) vectors

“…49 Viral mutants with modified tropism based on a selection process within a library of AAV clones with randomly modified capsids, the AAV display, allow to generate CLL-specific targeting vectors, but safety issues of these vectors have to be addressed before entering the clinic. 50 We have shown that after infection with AAV particles encoding CD40L, the immune accessory molecule CD80 was expressed on infected CLL cells, but also on noninfected bystander leukemia B cells. Similar results were previously described for an adenoviral transfer system and also for AAV vectors being used after prestimulation of CLL cells by CD40L-expressing feeder cells.…”