Co-injection of adenovirus expressing CTLA4-Ig prolongs adenovirally mediated lacZ reporter gene expression in the mouse retina

Abstract

There is growing interest in gene delivery to the eye in describes a strategy for prolonging gene expression by order to develop gene therapy for the many ocular disblocking the B7-CD28 interactions between antigen orders which may be amenable to this approach. To date, presenting cells (APC) and T cells in order to prevent the recombinant adenoviruses (AV) have been the main vector costimulatory signals required for T cell survival and proused for gene delivery to anterior and posterior segments liferation. This was achieved by the co-injection of AV in animal models. As with delivery to other organs, immune encoding a secreted immunomodulatory molecule (CTLA4-responses to vector and transgene limit the duration of Ig) which consists of the extra-cellular domain of mouse expression in the eye. Using an E1-deleted adenoviral vec-CTLA4 fused to the Fc region of human IgG. Subretinal cotor carrying a lacZ reporter gene, we have previously deminjection of AV encoding ␤ galactosidase with AV encoding onstrated that a T cell-mediated immune response reduces CTLA4-Ig results in prolonged expression in retinal cells the level of intra-ocular transgene expression over time compared with subretinal injection of only adenovirus and limits it to around 3 weeks in mice. This report encoding ␤ galactosidase. Keywords: gene therapy; immune response; photoreceptor; eyeThere is growing interest in gene transfer into various tissues of the eye since there are many ocular disorders which may be amenable to gene therapy. 1 Of these, there is particular interest in developing gene therapy for inherited retinal degenerations, some of which are due to single gene defects in photoreceptor-specific genes. These disorders may ultimately be treated by gene replacement strategies which require gene transfer to photoreceptors or by strategies which prevent these cells entering the apoptotic pathway. The latter might be achieved, for instance, by the delivery of genes encoding neurotrophic growth factors to the adjacent retinal pigment epithelium (RPE) cells or to cells in the anterior chamber. A number of vectors, including those based on herpes simplex virus (HSV), 2 lentivirus 3 and adeno-associated virus (AAV) [4][5][6][7] have been used for ocular gene transfer but, to date, the most widely reported system is that based on adenoviral (AV) vectors. [8][9][10][11][12][13][14][15][16][17][18][19] Studies in either the rabbit or more often the mouse, using these AV vectors carrying a lacZ reporter gene, have demonstrated that cells in the anterior segment, including the corneal endothelium, iris pigment epithelium, ciliary body, trabecular meshwork and Schlemms canal, may be efficiently transduced by intra-cameral injection. Subretinal injection is required for efficient targeting of the RPE and also results in the transduction of a small proportion of photoreceptors. Host immune responses to vector and transgene currently present a general problem for long-term gene delivery. There has been particular concern about the immunogenicity of A...

Immune response following intraocular delivery of recombinant viral vectors

“…One method to attain a constant supply of the protein is to deliver the relevant gene through virusmediated transduction. Ali et al 46 reported that local production of CTLA4-Ig through adenovirus-mediated gene transfer, can prolong adenovirally mediated reporter gene expression in the mouse retina. Similarly, cotreatment with other immunosuppressive agents extends transgene expression after intraocular injection of adenovirus.…”

“…Similarly, cotreatment with other immunosuppressive agents extends transgene expression after intraocular injection of adenovirus. 42,46,47 The cellular immune response mediated by adenovirus injection is likely because of the fact that this virus targets APCs. 48 What are the APCs in the eye that are infected by adenovirus?…”

Prospects for gene therapy of inherited retinal disease

“…The delivery of rAAV vectors into the subretinal space, for example, results in the transduction of photoreceptors and retinal pigment epithelial cells, whereas injection of the same vector into the vitreous targets only ganglion cells in the inner retina, at least in the fully developed retina. 5 Gene therapy for photoreceptor-based loss-of-function defects Considerable progress has been made in the development of gene replacement therapies for retinal degenerations resulting from gene defects in photoreceptor cells. rAAV-mediated gene replacement of peripherin, a structural protein critical for stability of discs in the photoreceptor outer segment, results in restoration of retinal ultrastructure and function in the rds mouse.…”

Changes in Adeno-Associated Virus-Mediated Gene Delivery in Retinal Degeneration

“…Intraocular injections were performed at three ages corresponding to three different stages of degeneration: P20 (early), P30 (intermediate), and P60 (advanced). As previously described, intravitreal injection of AAV1, 5, 8, and 9, at all ages tested, resulted in no measurable transgene expression in healthy rat retina, whereas AAV2 led to robust gene expression in the inner retina 3 weeks postinjection (Ali et al, 1998;Harvey et al, 2002;Auricchio, 2003;Buch et al, 2008;Lebherz et al, 2008). GFP expression begins rapidly in the TgS334ter-3 retina (5 days postinjection) for all serotypes except AAV2, which gave visible expression after 3 weeks.…”