Herpes simplex type-1 virus-based vectors for gene therapy

Recent advances in recombinant nucleic acid technologies and the understanding of the molecular biology of diseases provide the basis for gene therapy's ability to impact on the clinical practice of medicine. Herpes simplex virus type 1 (HSV-1) has features that make it suitable as a vector for gene therapy. These properties include: 1) wide host range and high efficiency of gene transfer; 2) large transgene capacity which is provided by deletion of genes unnecessary for viral replication; 3) unique ability of entering a state of latency in neurons; 4) specific oncolytic effect of some mutants by deletion of certain early genes. Three types of vectors designed for gene therapy have been developed from this virus, termed replication-defective vectors, replication-conditional vectors and amplicon vectors. In this review, we describe the recent advances in HSV-1-based vector systems and their applications for gene therapy.