Anti-Viral Gene Delivery in the Nervous System

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DESCRIPTION (provided by applicant): Based on the seroprevalence rate, between 150 and 200 million Americans are latently infected with herpes simplex virus type 1 (HSV-1) of which 20% will experience recurrent reactivation of latent virus. Most of the morbidity associated with HSV-1 infection is a result of the host's immune response to repeated viral reactivation. The reactivation elicits a destructive inflammatory response manifested by stromal scarring and infiltration of inflammatory cells into the stroma of the eye ultimately leading to blindness (HSV-1 is the leading cause of infectious blindness in the industrialized world). Following acute infection, HSV-1 establishes a latent infection within the neurons of the sensory ganglia innervating the infected tissue; in the case of the eye, the trigeminal ganglia. Recently, we have found the delivery of a potent anti-viral transgene encoding for interferon (IFN)-beta into the cornea results in the translocation of the transgene to neurons in the trigeminal ganglia. The transgene is active in the trigeminal ganglia evident by the up-regulation of the IFN-responsive gene, 2'-5' oligoadenylate synthetase and strong suppression of HSV-1 replication. Preliminary data also shows that the reactivation of latent HSV-1 in the trigeminal ganglia following explantation of the ganglia in culture is significantly reduced in both occurrence (percent reactivation) and viral yield when explants are transduced with the IFN-beta transgene at the time of initiation of culture. However, the current method of transgene delivery via an adenovirus vector is hindered by the lack of prolonged transgene expression, the immunogenicity of the vector, and the targeted cells. We propose to develop a novel form of transgene delivery using a promoter for prolonged expression in an amplicon HSV vector in order to target those neurons that are specifically latently infected with HSV-1 and antagonize virus reactivation. In order to accomplish this task we will generate a cassette expressing the IFN-beta transgene under a beta-actin promoter and clone it into a HSV amplicon vector (contains only the origin of DNA replication and a DNA cleavage/packaging signal (no antigenicity associated with the vector) in order to use this HSV amplicon to test the hypothesis that the IFN-beta transgene delivered in this manner will antagonize HSV-1 reactivation in vitro and in vivo over time.