HSV-1 Amplicon Vectors—Simplicity and Versatility

A large number of viral vector systems, including those based on herpes simplex virus type 1 (HSV-1), retrovirus, adenovirus, and adeno-associated virus (AAV), have been developed over the past two decades. Reducing or eliminating toxic components, while conserving the efficiency of gene transfer, has been the primary goal of these efforts. All currently available vector systems have their advantages and disadvantages (see Table 1). HSV-1-based vectors, both recombinant HSV-1 vectors and HSV-1 amplicons, exploit most of the advantages of the parent virus, including (i) a broad host range and the ability to transduce both dividing and nondividing cells; (ii) a transgene capacity of theoretically up to 150 kb, which allows insertion of multiple transcription units and/or elements from other viruses to create hybrid vectors; (iii) high stability of the virion; and (iv) relatively high titers (for reviews, see 1–3).