01. Gene therapy Boulikas.pdf - Gene therapy & Molecular Biology

A clinical protocol proposed recently for the therapy of
amyotrophic lateral sclerosis uses a semipermeable
membrane to enclose the ex vivo modified xenogenic BKH
cells which is implanted intrathecally to provide human
ciliary neurotrophic factor; the membrane prevents
immunologic rejection of the cells interposing a virus
impermeable barrier between the transduced cells and the
host (Deglon et al, 1996; Pochon et al, 1996); the method
has been applied before for cross-species transplantation
of a polymer-encapsulated dopamine-secreting cell line to
treat Parkinson's disease and for the delivery of nerve
growth factor in rat and primate models of the Alzheimer's
disease (Kordower et al, 1994; see Pochon et al, 1996 for
more references). Evidently, similar approaches could be
used to protect adenovirus- and retrovirus-transduced
syngeneic cells from immunologic rejection provided that
the therapeutic protein is secreted.
A new area of investigation is directed toward surface
modification of recombinant adenoviruses to render them
safer and to minimize the strong immune responses
against the virus and virus-infected cells; to this end
Fender et al (1997) proposed a dodecahedron made of
adenovirus pentons or penton bases and having only one
or two adenovirus proteins instead of the 11 contained in
an adenovirus virion; the penton is a complex of two
oligomeric proteins, a penton base and fiber, involved in
Figure 2. Localization of a recombinant adenoviral
vector carrying 6.3 kb of dystrophin cDNA by in situ PCR
following intramuscular injection to immunosuppressed
mdx mice. Shown are transverse cryostat sections of mdx
tibialis anterior muscle. Panel A shows a strong in situ
hybridization signal (an E4 adenoviral sequence was
amplified and an E4 probe was used) in myonuclei of an
immunosuppressed animal injected with E1, E3-deleted
adenovirus at 30 days postinjection (magnification 650x).
Panel B was produced without Taq polymerase during PCR
as a negative control. Panel C shows an uninjected muscle
Boulikas: An overview on gene therapy
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the cell attachment, internalization, and liberation of virus
from endosomes.
It is certain that great improvements in adenoviral gene
delivery will solve many of the current problems and
permit a higher therapeutic efficacy in the near future.
G. Examples of adenoviral gene transfer
Recombinant adenovirus vectors have been used: for
the transfer of factor IX gene in hemophilia B dogs via
vein injection (Kay et al, 1994) and in mice (Smith et al,
1993); for the transfer of genes into neurons and glia in the
brain (le Gal la Salle, 1993); for the transfer of the gene of
ornithine transcarmylase in deficient mouse and human
hepatocytes (Morsy et al, 1993); for the transfer of the
VLDL receptor gene for treatment of familial
hypercholesterolaemia in the mouse model (Kozarsky et
al, 1996); for the transfer of low density lipoprotein
receptor gene in normal mice (Herz and Gerard, 1993);
and for the ex vivo transduction of T cells from ADAdeficient
patients (Blaese et al, 1995; Bordignon et al,
1995). The adenovirus major late promoter was linked to a
human α1-antitrypsin gene for its transfer to lung epithelia
of cotton rat respiratory pathway as a model for the
treatment of α1-antitrypsin deficiency; both in vitro and in
vivo infections