Transient immunosuppression with FK506 permits long-term expression of therapeutic genes introduced into the liver using recombinant adenoviruses in the rat

Abstract

The host immune response limits the duration of ex-The use of recombinant retroviruses and adenoviruses for pression of adenovirally transduced genes and precludes somatic gene therapy is being extensively explored. Although long-term gene expression upon re-administration of the retroviruses are able to induce long-term transgene expresvirus. In this study we wished to evaluate whether short-sion because of their integration into the host genome, the term immunosuppression of the host, at the time of recom-utility of these vectors in transferring genes into the liver in binant virus administration, would allow expression of vivo is limited because retroviruses do not transduce nonthe therapeutic gene product upon virus reinjection. Gunn dividing cells.1 Recombinant adenoviral vectors offer a numrats were used as recipients of recombinant adenoviruses ber of advantages for use in gene therapy. These viruses can expressing human BUGT (Ad-hBUGT) or E. coli b-galac-be generated at high titers, transfer foreign genes with high tosidase (Ad-LacZ). Rats were treated with FK506 (1-1.5 efficiency, have a broad host range, and do not require cell mg/kg, per OS daily) for three days beginning 24 hours proliferation for infection to occur.2-6 Despite these advanbefore each virus injection. Control groups did not receive tages, the efficacy of adenoviral vectors in gene therapy has any immunosuppressant. The serum bilirubin level was been severely limited because of lack of integration into the reduced from 7.1 { 0.75 mg/dL to 2.0 { 0.7 mg/dL within host genome, as well as the generation of an anti-viral host two days of viral injection in both FK506 treated and immune response which precludes gene expression upon recontrol groups, and then gradually increased in 6 weeks. injection of the recombinant adenovirus. 7-10 FK506-treated rats had low or undetectable antibody titersWe 11 and others 12 have shown that tolerization of recipient against the recombinant adenovirus and minimal or no animals by administration of recombinant adenovirus in the cytotoxic T lymphocyte (CTL) response against adenovi-neonatal period inhibits the development of antibodies and rus-infected cells. The tolerized rats received two subse-of virus specific cytotoxic T lymphocytes (CTL). Similarly, quent injections 42 and 98 days after the first injection, intrathymic inoculation, 13 or oral administration 14 of adenowhich reduced the bilirubin levels again to 2.0 { 0.56 and viral proteins, can tolerize the host to recombinant adenovi-2.2 { 0.61 mg/dL, respectively. In contrast, control rats ruses, thereby permitting therapeutic gene expression followdeveloped high titer neutralizing antibodies and a CTL ing re-administration of the virus. To explore whether the response, and their serum bilirubin levels were not re-development of an immune response in adult recipients can duced following subsequent injections. We conclude that be prevented by short-term immunosuppression around the short-term FK506 treatment around the time of virus ad-time of virus ...

Electrotransfer of naked DNA in the skeletal muscles of animal models of muscular dystrophies

“…[54][55][56][57][58] FK506 has been used previously to prevent the rejection of transgene products brought in recipient animals by cellular or viral vectors. [37][38][39][40][41][42][43][44] Our present results indicate that the specific immune reactions are blocked by the permanent or discontinuous administration of the FK506 immunosuppressant. The protection, however, fades away and the number of ␤-gal-positive fibers decreases with time after termination of FK506.…”

“…For instance, FK506 blocked the cellular and humoral rejection of transgene products in cell-or virus-mediated gene transfer in mice. [38][39][40][41][42][43][44] Therefore, in the present study, FK506 was used to prevent the rejection of transduced muscle fibers by the mature, adult immune system of the recipient mice. As expected, the daily immunosuppression of animals following transduction led to the persistency of a high percentage of labeled fibers for several weeks in wild-type mice.…”

Transient cyclophosphamide treatment before intraportal readministration of an adenoviral vector can induce re-expression of the original gene construct in rat liver

“…It has been demonstrated that treatment regimens with immunosuppressive drugs such as cyclophosphamide, FK506, cyclosporin A and deoxyspergualin, around the time of initial exposure to adenoviruses permit prolonged transgene expression, reduce inflammation, prevent the formation of neutralizing antibodies and allow the successful readministration of adenoviral vectors. [24][25][26][27] Administration of monoclonal antibodies that reduce immune responses, such as anti-CD40 ligand antibody and CTLA4Ig, around the time of the first vector administration has also been shown to be effective in preventing the formation of neutralizing antibodies against adenovirus and in permitting the successful secondary administration of adenoviral vectors. [28][29][30][31][32] The practicality of these approaches is, however, questionable because the majority of prospective gene therapy patients have already been infected with adenovirus serotype-2 and -5.…”

Liver gene therapy: advances and hurdles

“…Many groups demonstrated that various immunomodulatory treatments might help to achieve permanent expression of a transgene. This was particularly demonstrative with drugs such as cyclophosphamid, FK506, CTLA4Ig, etc having the capability to subvert the immune system transiently [24][25][26][27] Similarly, induction of tolerance to the transgene product or to the adenovirus proteins was achieved by various approaches. On the other hand, a second group of strategies relied on modification of the vector itself to reduce immune response.…”