Persistence of Replication-Deficient Adenovirus-Mediated Gene Transfer in Lungs of Immune-Deficient (nu/nu) Mice

Abstract

To evaluate the role of cell-mediated immunity during gene transfer to the respiratory epithelium, the time course of luciferase activity was assessed after intratracheal administration of Av1Luc1, an E1a-E3-deleted adenoviral (Ad5) vector expressing firefly luciferase, to FVB/N, BALB/c and BALB/c-nu/nu adult mice. Adenovirus-mediated luciferase activity was rapidly lost from the respiratory tract between 2 and 14 days after treatment of both FVB/N and BALB/c wild-type mice. In the wild-type mice, loss of luciferase activity was associated with an early inflammatory response consisting of infiltration with macrophages and polymorphonuclear leukocytes and a more prolonged response characterized by lymphocytic infiltration. In the immune-deficient nu/nu mice, luciferase activity was maintained at higher levels than in immune-competent mice after exposure to virus and was associated with a distinct pattern of inflammation, consisting primarily of macrophages and polymorphonuclear cells but lacking the lymphocytic infiltrates typical of the inflammation in wild-type mice. Adenoviral DNA was rapidly cleared from the lungs of both nu/nu and wild-type mice. Markedly increased expression of proliferating cell nuclear antigen (PCNA) was observed in bronchiolar and alveolar epithelial cells and in inflammatory cells after exposure to Av1LUc1. The proliferative response of the respiratory epithelium was more extensive and persistent in wild-type than in nu/nu mice. To assess further the impact of the immune system on adenovirus-mediated gene expression, cotton rats treated with cyclosporin A or dexamethasone were exposed to Av1Luc1. Both agents decreased lung inflammation and significantly increased lung luciferase activity. The loss of lung luciferase activity is dependent, in part, on the immune-mediated clearance of respiratory epithelial cells, which may limit the extent and duration of gene expression with recombinant adenoviral vectors.

Pulmonary inflammation associated with repeated, prenatal exposure to an E1, E3-deleted adenoviral vector in sheep

“…[1][2][3][4][5][6] Gene expression is transient and appears to be limited by host inflammatory and immune responses to adenoviral proteins. 2,4,[7][8][9][10] Adenovirus-mediated gene transfer and expression are more effective when the ability of the recipient's immune system to respond to vector administration is suppressed. Thus, when first generation adenovirus vectors are administered with dexamethasone, cyclosporin or interleukin inhibitors or to immunodeficient mice, gene expression outlasts that produced by adenovirus vectors administered alone to immunocompetent animals.…”

“…Thus, when first generation adenovirus vectors are administered with dexamethasone, cyclosporin or interleukin inhibitors or to immunodeficient mice, gene expression outlasts that produced by adenovirus vectors administered alone to immunocompetent animals. 8,9 An alternative approach is to initiate gene therapy before immune recognition and inflammatory responses have matured. In the newborn mouse, in which immune recognition mechanisms have not fully developed, 11 adenovirus-mediated gene expression is prolonged compared to that in the adult mouse.…”

Intracerebral injection of adenovirus harboring the HSVtk gene combined with ganciclovir administration: toxicity study in nonhuman primates

“…In rat and mouse lung and liver tissue this phase is characterized by the presence of mononuclear cells (especially macrophages) and polymorphonuclears. 30,43 After virus injection into the rat brain, however, polymorphonuclear cells are almost always absent. 25,29 The second phase of the immune response is often attributed to low level expression of viral proteins.…”

Creation of immune ‘stealth’ genes for gene therapy through fusion with the Gly-Ala repeat of EBNA-1

“…[13][14][15][16] This requires prior activation of CD4 þ T cells. 1,[16][17][18][19][20][21][22][23] Also in primates a CTL response directed against the transgene product has been shown to occur. 24,25 In a clinical trial aiming at inducing a graft versus leukemia response, eight of 24 treated patients developed a specific cytotoxic CD8 þ T-cell-mediated immune response against the cells genetically engineered to express the Herpes Simplex Virus 1 (HSV1) thymidine-kinase (TK) gene.…”

“…25 Previous attempts to reduce the T-cell responses against the neoantigens during gene therapy focused on blocking the MHC class I-and class II-restricted T-cell responses, or the prevention of costimulation of T cells. 14,[18][19][20][26][27][28] However, these approaches were either not fully effective or resulted in a general immunosuppression. The ideal strategy would selectively prevent the presentation by MHC class I of the transgene-derived peptides.…”