Ocular herpes simplex virus type 1 (HSV-1) infection leads to the establishment of a permanent reservoir of virus in neural tissues; periodic reactivation, triggered by stimuli such as trauma, stress, surgery, or immunosuppressive drugs, allows virus to travel to the cornea, causing recurrent infections that lead to stromal scarring and ultimately reduced vision and/or blindness. Antiviral drugs can mitigate the effects of individual episodes, but NO drug or therapy can eliminate the latent virus from the ganglion or prevent reactivation r recurrent ocular disease. The objective of this research is to elucidate the molecular mechanisms that underlie the reactivation of latent HSV-1 from the trigeminal ganglion and the recurrence of ocular herpetic disease. To this end, a variety of studies involving HSV DNA and the RNAs designated as latency associated transcripts (LAT) will be undertaken using rabbit, mouse, and monkey models of HSV ocular disease, ganglionic latency, and reactivation. The studies will 1) evaluate the relationship between the production of LAT and e efficiency of in vivo reactivation using HSV strains with genetically engineered variations in the LAT region the DNA; 2) examine the time-course of changes in the amount of HSV DNA and the amount and localization LAT after induced reactivation in animals harboring latent HSV strains previously characterized by high, ow, and variable rates of reactivation; 3) seek to identify reproducible associations between subpopulations neuronal cells and the presence of LAT; 4) investigate the relationship between the appearance of T-lymphocytes in neural and ocular tissues and the amount and localization of LAT during the development HSV latency and the onset of virus reactivation; 5) identify the appearance of virus-specific RNAs in neural is at various times after iontophoretic induction of ocular reactivation of latent HSV; 6) determine the effect intensive antiviral therapy on the amount of HSV DNA and on the amount and localization of LAT in the neural tissue after induced reactivation; and 7) characterize the pharmacologic mechanism(s) that underlie adrenergic induction of HSV reactivation and recurrent disease. The methodology to be employed includes iontophoresis of adrenergic agents,.particularly epinephrine, for reactivation of latent virus, the polymerase n reaction (PCR) for quantification of HSV DNA and RNA, including LAT, PCR for identification of virus-specific RNAs, and in situ hybridization for localization of LAT. The long-term goal of this research is to use this basic information to develop therapeutic strategies that will block the reactivation of latent HSV-1 from neural tissues and thereby prevent the devastating visual consequences of recurrent ocular herpetic disease.
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