Development of Replication-Defective Herpes Simplex Virus Vectors

Numerous diseases of the nervous system result from single gene or multifactorial gene defects such as cancer, immune pathological disorders, metabolic diseases, and common neurodegenerative syndromes (Parkinson’s and Alzheimer’s diseases). A greater understanding of the molecular, biochemical, and genetic factors involved in the progression of a specific disease state has led to the development of genetic therapies using direct gene transfer to ameliorate the disease condition or correct a genetic defect in situ. Standard gene therapeutic approaches employing retroviruses have not proven feasible for treating disorders of the central nervous system (CNS) since these vectors require dividing cells for integration and expression of the transgene, whereas CNS neurons are postmitotic, terminally differentiated cells. Thus, methods for delivery and expression of therapeutic gene products to treat CNS disease will require new delivery strategies and vehicles including the development of novel vectors for direct gene transfer. These vectors should: efficiently deliver the therapeutic gene(s) to a sufficient number of nondividing neurons; persist long-term in a nonintegrated state within the nerve cell nucleus without disturbing host cell functions; and be able to regulate therapeutic gene expression for diseases that may either require high-level transient transgene expression or continuous low level synthesis of the therapeutic product

Construction of Replication Defective Herpes Simplex Virus Vectors.

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Gene transfer to muscle and spinal cord using herpes simplex virus-based vectors.

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Herpes Simplex Virus mediated gene transfer to neurons.

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Expression of HSV-1 receptors in EBV-associated lymphoproliferative disease determines susceptibility to oncolytic HSV

Item does not contain fulltextEpstein-Barr virus (EBV)-associated B-cell lymphoproliferative disease (LPD) after hematopoietic stem cell or solid organ transplantation remains a life-threatening complication. Expression of the virus-encoded gene product, EBER, has been shown to prevent apoptosis via blockade of PKR activation. As PKR is a major cellular defense against Herpes simplex virus (HSV), and oncolytic HSV-1 (oHSV) mutants have shown promising antitumor efficacy in preclinical models, we sought to determine whether EBV-LPD cells are susceptible to infection by oHSVs. We tested three primary EBV-infected lymphocyte cell cultures from neuroblastoma (NB) patients as models of naturally acquired EBV-LPD. NB12 was the most susceptible, NB122R was intermediate and NB88R2 was essentially resistant. Despite EBER expression, PKR was activated by oHSV infection. Susceptibility to oHSV correlated with the expression of the HSV receptor, nectin-1. The resistance of NB88R2 was reversed by exogenous nectin-1 expression, whereas downregulation of nectin-1 on NB12 decreased viral entry. Xenografts derived from the EBV-LPDs exhibited only mild (NB12) or no (NB88R2) response to oHSV injection, compared with a NB cell line that showed a significant response. We conclude that EBV-LPDs are relatively resistant to oHSV virotherapy, in some cases, due to low virus receptor expression but also due to intact antiviral PKR signaling