Gene Delivery Using Viral Vectors - Challenges in Delivery of Therapeutic Genomics and Proteomics - page 214

Table 5.2 Cell Lines That Can Be Used for Adenoviral Production

Cell Lines Production

HEK293 cells For packaging, the adenoviral DNA was sheared by passage through a

22-gauge needle and then introduced into the HEK293 cells by calcium
phosphate transfection. In HEK293 cells, the E1 gene (nucleotides 1-
4344 of Ad5) is located on chromosome 19-19q13.20. HEK293 cells are
the most commonly used cell line for producing adenovirus that provides
the E1 protein in trans , allowing the adenovirus to replicate in the cells

911 cells Human embryonic retinoblast (HER); Fallaux, one of the established

HER cell lines, called 911, is demonstrated to have several characteristics
in common with the HEK293 cell line: the 911 cells perform particularly
well in plaque assays. Upon infection with E1-deleted adenoviruses,
plaques become apparent in monolayers of 911 cells after 3-4 days
versus 4-10 days in monolayers of HEK293 cells, thereby reducing the
time required for quantitative plaque assays. With 911 cells, the yields
from E1-deleted adenovirus can be up to three times greater than those
achieved with HEK293 cells. Finally, the Ad5-DNA content of the 911-
cell line is completely known. The 911 cell line has higher transfectable
efficiency and exhibits similar frequencies of homologous recombination.
However, it has additional characteristics that make it a useful alternative
for HEK293

PER.C6 cells PER cells contain the Ad serotype 5 (Ad5) E1A- and E1B-encoding

sequences (Ad5 nucleotides 459-3510) under the control of the human
phosphoglycerate kinase (PGK) promoter. PER cells synthesize high
levels of the Ad5 E1A and E1B proteins. The yields from PER cells of
E1-deleted Ads are similar to those obtained from earlier helper cells,
such as 911 and 293 cells

GH329 cells Derived from HeLa cells, it is the HeLa-based cell line called GH329

that stably expresses the E1 locus from a promoter derived from the
phosphoglycerate kinase gene. Overlap sequences with a standard
E1-deleted vector that retains full pIX transcriptional unit have been
eliminated at the 5 end and minimized at the 3 end. The GH329 cell
line forms plaques and produces E1-deleted adenovirus as efficiently as
HEK293 cells

increase of the inserted foreign DNA to size 7 or 8 kb is possible with the E1/E3
deletion of Ad vectors, but it was found to be very difficult. The potential problem of
the first-generation adenoviral vector is pathogenic toward the adenovirus backbone
[11-15] . The ability of the virus to produce other viral proteins is not completely
eliminated by reducing the loss of E1 function [16,17] . This may be from toxic
effects of first-generation adenovirus vectors after transduction in vivo . Generally,
transient expressions of therapeutic genes in vivo produced by the first-generation
vectors, primarily due to leaky expression of viral genes, lead to immune responses
against viral-transduced cells [18] .