Long-lasting adenovirus transgene expression in mice through neonatal intrathymic tolerance induction without the use of immunosuppression

Abstract

The major barrier to the clinical application of adenovirus gene therapy for diseases that require stable transgene expression is the immunogenicity of recombinant adenovirus, which ordinarily limits the duration of its effects to a period of about 2 weeks. We postulated that tolerance to adenovirus could be induced and transgene expression could be prolonged if T lymphocytes underwent thymic selection in the presence of adenovirus antigens. Mice were inoculated in the thymus with a recombinant adenovirus containing the lacZ marker gene during the neonatal period at a time before T-cell maturation had occurred. When the virus was administered intravenously to these mice in adulthood, they were found to have an impaired adenovirusspecific cytotoxic T-lymphocyte response which allowed prolonged hepatic lacZ expression, for up to 260 days. The ability to achieve unresponsiveness to a recombinant adenovirus after inoculation of the thymus in neonates extends the paradigm of intrathymic tolerance induction. Furthermore, this model will enable the study of stable adenovirus transgene expression in vivo without the use of immunosuppression and ultimately may have clinical utility.

Intrathymic adeno-associated virus gene transfer rapidly restores thymic function and long-term persistence of gene-corrected T cells

“…We next assessed whether the reconstituted mice exhibited an immune response against the ZAP-70 transgene. Intrathymic expression of the injected transgene likely minimizes an immune response, enhancing deletion of autoreactive thymocytes, 33,35 but our findings of a T cell-independent anti-capsid neutralizing activity (Fig 5, B) suggested the possibility of an anti-transgene response. Although anti-ZAP-70 antibodies were not detected at 3 weeks after AAV8-ZAP-70 transduction, 5 of 7 mice harbored antibodies at 10 weeks (>25 ng/mL sera; P < .01).…”

“…[20][21][22][23] Notably, however, intrathymic injection of HSCs, as well as pro-T cells, improves T-cell differentiation in the thymus [24][25][26][27][28][29][30][31] and increases the expansion of supporting thymic epithelial cells (TECs). 32 Additionally, the thymus can be targeted through direct injection of antigens or vectors expressing genes of interest, [33][34][35][36][37] with recombinant adeno-associated virus (rAAV) vectors transducing thymocytes with a 10-fold greater efficiency than lentiviral vectors. 34,37 Indeed, rAAV vectors hold great promise for gene transfer therapies because they are capable of infecting nondividing cells, and particles of high titer and purity can be produced.…”

GM-CSF expands dendritic cells and their progenitors in mouse liver

“…Recombinant adenoviruses were propagated, purified, and stored as previously described. 18 AdGM-CSF (AdGM), AdLDLR, and AdGFP (Quantum Biotechnologies, Montreal, Quebec, Canada) encode murine GM-CSF, human low-density lipoprotein receptor, and green fluorescent protein, respectively, under the control of the cytomegalovirus promoter. 16,19 AdLDLR and AdGFP served as control viruses, and no differences were observed between their effects.…”

Efficient, Repeated Adenovirus-Mediated Gene Transfer in Mice Lacking both Tumor Necrosis Factor Alpha and Lymphotoxin α

“…For example, a recombinant adenovirus encoding the interleukin-1 (IL-1) receptor antagonist was tested but failed to block virus-induced inflammation (40). In another study, tolerance induction following intrathymic or oral administration of adenoviral antigens was shown to be effective in abrogating the recognition phase due to the deletion or anergy of the cognate lymphocytes, translating into long-term gene delivery and efficient readministration (10,28,58). Administration of immunosuppressive drugs such as cyclophosphamide or cyclosporine has also been used to block the cellular and humoral arms of the immune response (50).…”