Induction of central tolerance by intrathymic inoculation of adenoviral antigens into the host thymus permits long-term gene therapy in Gunn rats.

Abstract

Recombinant adenoviruses are highly efficient at transferring foreign genes in vivo. However, duration of gene expression is limited by the host antiviral immune response which precludes expression upon viral readministration. We tested the feasibility of prolonging gene expression by induction of central tolerance to adenoviral antigens in bilirubin-UDP-glucuronosyltransferase-1 (BUGT 1 )-deficient Gunn rats. Tolerance was induced by intraperitoneal injection of antilymphocyte serum, followed by intrathymic inoculation of one of the following: a recombinant adenovirus (Ad), adenovirus human UDP-glucuronosyltransferase (Ad-hBUGT 1 ) carrying the hBUGT 1 gene; a protein extract of the same virus; or viral infected hepatocytes. Controls received intrathymic injections of normal saline. After 12 d all groups were injected intravenously with 5 ϫ 10 9 pfu of either Ad-hBUGT 1 or adenovirus ␤ -galactosidase (Ad-LacZ) (expressing the Escherichia coli ␤ -galactosidase [LacZ] gene). In all three groups of tolerized rats, hBUGT 1 was expressed in the liver after administration of Ad-hBUGT 1 , with glucuronidation of biliary bilirubin of above 95%. Serum bilirubin levels decreased from 7.2 to 1.8 mg/d1 within 1 wk and remained low for 7 wk. Similar findings were observed following repeat injections given on days 45 and 112. In control rats serum bilirubin levels were reduced for only 4 wk, and viral readministration was ineffective. In all tolerized groups, but not in controls, there was a marked inhibition of appearance of neutralizing antibodies and cytotoxic lymphocytes against the recombinant adenovirus. Injection of wild type adenovirus-5 (Ad5) into the tolerized rats elicited a wild type-specific cytotoxic lymphocyte response. This is the first demonstration of Ad-directed long-term correction of an inherited metabolic disease following central tolerization with thymic antigen. ( J. Clin. Invest . 1996. 98:2640-2647.)

A non-immunogenic adenoviral vector, coexpressing CTLA4Ig and bilirubin-uridine-diphosphoglucuronateglucuronosyltransferase permits long-term, repeatable transgene expression in the Gunn rat model of Crigler–Najjar syndrome

“…This conclusion would be consistent with the observation by other investigators that intravenous injection of CTLA4Ig alone did not prevent the immune response to adenovectors. The effect of CTLA4Ig is in contrast to a permanent state of tolerance that occurs after injection of recombinant adenoviruses in neonatal rats 4 after intrathymic injection of adenoviral antigens 5 or oral tolerization to adenoviral proteins. 6 In each of these cases, first generation adenoviral vectors could be administered repeatedly into rodents without significant immune response.…”

“…[4][5][6][7][8] A plasmid containing the full-length cDNA of murine CTLA4Ig downstream to the cytomegalovirus immediate-early promoter-enhancer (obtained from J Bradshaw, Bristol-Meyers Squibb, Princeton, NJ, USA) was partially digested with EcoRI. The CTLA4Ig coding region, along with the CMV promoter was subcloned into the adenovirus shuttle vector p⌬E1sp1A/EcoR1 (Microbix Biosystems, Toronto, Ontario, Canada) in an anti-clockwise direction, generating p⌬E1-CTLA4Ig.…”

“…One group of strategies aimed at tolerization of the host to adenoviral antigens involves modification of the host immune system. Administration of adenoviral vectors in neonatal rats, 4,14 intrathymic injection of adenoviral proteins 5 or oral administration of small doses of adenoviral proteins 6 have resulted in tolerization of rodents to adenoviral antigens, permitting repeated gene transfer. A second group of strategies involve modification of the viral vector.…”

Liver–Associated Lymphocytes Expressing Nk1.1 Are Essential for Oral Immune Tolerance Induction in A Murine Model

“…Moreover, oral tolerance was effective in the presence of preexisting anti-adenovirus immunity in animals, and was superior to other methods of immune tolerance induction. 18,[23][24][25][26] Oral tolerance has been used in humans in the treatment of autoimmune diseases such as rheumatoid arthritis, diabetes mellitus, and multiple sclerosis. 2,27 Although the procedure is well established as a FIG.…”

Gene Therapy for Inherited Hyperbilirubinemias

“…12 Tolerance can be induced also by injecting adenoviral proteins into the thymus of young, adult rats. 13 Tolerization of the host to adenoviruses by oral feeding of adenoviral proteins in low doses not only permits repeat administration in naive hosts, but also allows administration in preimmunized hosts. 14 Alternatively, coadministration of the immunosuppressive agent FK-506 for 3 days around the time of administration of adenoviruses prevents both cellular and humoral immune responses.…”