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Production of helper‐dependent adenovirus vector relies on helper virus structure and complementing
Author(s) -
Zhou Heshan Sam,
Zhao Tiejun,
Rao X. Mei,
Beaudet Arthur L.
Publication year - 2002
Publication title -
the journal of gene medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.689
H-Index - 91
eISSN - 1521-2254
pISSN - 1099-498X
DOI - 10.1002/jgm.301
Subject(s) - helper virus , vector (molecular biology) , virus , biology , virology , viral vector , viral replication , adenoviridae , gene , genetics , genetic enhancement , recombinant dna
Background The helper‐dependent (HD) adenoviral (Ad) vector relies on a helper virus to provide viral proteins for vector amplification. HD‐Ad vectors can significantly increase therapeutic gene expression and improve safety. However, the yield of an HD‐Ad vector is generally lower than that of an E1‐deleted first‐generation vector, likely due to the alterations in viral E3 or packaging regions of a helper virus that attenuate its replication and complementing for an HD‐Ad vector. Methods To study this question and improve HD‐Ad vector production, we have generated four different helper viruses with a wild‐type or deleted E3 region, and with a relocated lox P. We have also constructed a first‐generation vector with a wild‐type E3 region and without the lox P site. We compared the replication of these viruses in Cre‐positive and ‐negative cells and studied their complementing for HD‐Ad vector production. Results Viruses with deleted E3 formed smaller plaques and produced lower titer compared with viruses containing the E3 region. The site where a lox P is inserted can also affect virus replication. Higher yield of HD‐Ad vector was obtained when a helper virus with wild‐type E3 was used. We also showed that deletion of the packaging signal in a helper virus through lox P/Cre interaction decreased the viral DNA complementing ability. Conclusions Although the E3 region is not essential for adenovirus replication in vivo , deletion of this region attenuates virus replication. Production of HD‐Ad vector can be further improved by modifications in helper virus structure. Copyright © 2002 John Wiley & Sons, Ltd.