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

However, CsA also inhibits the activity of TBP required
for transcription from the adenovirus major late promoter.
Recombinant adenovirus-transduced cells were able to
elute host immune surveillance in dogs by cyclosporin A
treatment (Fang et al, 1995). Similar conclusions were
reached by Dai and coworkers (1995) using adenoviral
vectors for delivering the canine factor IX gene into the
hind leg muscle of mice: whereas in nude mice a high
level of expression of FIX protein was detectable for 300
days, expression of FIX protein lasted for 7-10 days in
normal mice. CD8 + lymphocytes were localized in the site
of injection; both cell-mediated and humoral immune
responses were found to be responsible for eliminating the
adenovirus-infected cells from the organism.
Recently, successful transduction of the mouse liver in
vivo after a single hepatic gene transfer of F.IX cDNA in
an AAV vector was achieved; persistent and curative
concentrations of functional human factor IX were
detected in the blood of the animals (Snyder et al, 1997).
Intramuscular injection of a recombinant AAV vector
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expressing human factor IX (hF.IX) into hindlimb muscles
of C57BL/6 mice and Rag 1 mice demonstrated the
presence of hF.IX protein by immunofluorescence staining
of muscles harvested 3 months after injection; however,
no hF.IX was detected in the plasma of immunocompetent
C57BL/6 mice because these animals had developed
circulating antibodies to hF.IX. Rag 1 mice on the other
hand, which carry a mutation in the recombinase
activating gene-1 and thus lack functional B and T cells,
displayed therapeutic levels (200-350 ng/ml) of F.IX in
the plasma in addition to muscle cells; F.IX levels
gradually increased over a period of several weeks before
reaching a plateau that was stable 6 months after injection.
Furthermore, these studies have demonstrated
colocalization of hF.IX and collagen IV in interstitial
spaces between muscle fibers; this was explained
following identification of collagen IV as a F.IX-binding
protein (Herzog et al, 1997).