Herpes simplex virus type-1 amplicon vectors for vaccine generation in acute lymphoblastic leukemia

Polycistronic Herpesvirus Amplicon Vectors for Veterinary Vaccine Development

Heterologous virus-vectored vaccines, particularly those based on canarypox virus vectors, have established a firm place in preventive veterinary medicine. However, herpesvirus-based vaccines have paved the way for DIVA vaccines (discrimination of infected against vaccinated animals), which are particularly desirable for highly contagious livestock diseases that are otherwise combatted by culling of infected animals.In this chapter, we describe the design, the preparation, and the testing of a polycistronic herpesvirus amplicon vaccine against rotaviruses with a particular emphasis on generating heterologous virus-like particles for immunization. After the design, the procedure consists of three steps, first, transient expression of the construct in cell cultures, second, expression and antibody response in a mouse model, and third, application of the system to the desired host species. As a whole, the present information will facilitate the design of novel vaccines of veterinary interest from the designing process until pre-licensing.

HSV as a vector in vaccine development and gene therapy

The very deep knowledge acquired on the genetics and molecular biology of herpes simplex virus (HSV), major human pathogen whose lifestyle is based on a long-term dual interaction with the infected host characterized by the existence of lytic and latent infections, has allowed the development of potential vectors for several applications in human healthcare. These include delivery and expression of human genes to cells of the nervous system, selective destruction of cancer cells, prophylaxis against infection with HSV or other infectious diseases and targeted infection of specific tissues or organs. Three different classes of vectors can be derived from HSV-1: replication-competent attenuated vectors, replication-incompetent recombinant vectors and defective helper-dependent vectors known as amplicons. This chapter highlights the current knowledge concerning design, construction and recent applications, as well as the potential and current limitations of the three different classes of HSV-1-based vectors.

HSV-1 amplicon vectors: a promising and versatile tool for gene delivery

Amplicons are defective and non-integrative vectors derived from herpes simplex virus type 1. They carry no virus genes in the vector genome and are, therefore, not toxic to the infected cells or pathogenic for the transduced organisms, making these vectors safe. In addition, the large transgenic capacity of amplicons, which allow delivery of < or = 150 Kbp of foreign DNA, make these vectors one of the most powerful, interesting and versatile gene delivery platforms. Here, the authors present recent technological developments that have significantly improved and extended the use of amplicons, both in cultured cells and in living organisms. In addition, this review illustrates the many possible applications that are presently being developed with amplicons and discuss the many difficulties still pending to be solved in order to achieve stable and physiologically regulated transgenic expression.

Effect of promoter strength on protein expression and immunogenicity of an HSV-1 amplicon vector encoding HIV-1 Gag

Helper-free herpes simplex virus type-1 (HSV-1) amplicon vectors elicit robust immune responses to encoded proteins, including human immunodeficiency virus type-1 (HIV-1) antigens. To improve this vaccine delivery system, seven amplicon vectors were constructed, each encoding HIV-1 Gag under the control of a different promoter. Gag expression levels were analyzed in murine and human cell lines, as well as in biopsied tissue samples from injected mice; these data were then compared with Gag-specific T cell responses in BALB/c mice. The magnitude of the amplicon-induced immune response was found to correlate strongly with the level of Gag production both in vitro and in vivo. Interestingly, the best correlation of the strength of the amplicon-induced immune response was with antigen expression in cultured DC rather than expression at the tissue site of injection or in cultured cell lines. These findings may have implications for the generation of improved HSV-1 amplicon vectors for HIV-1 vaccine delivery.