The fate of exogenous virus genes inserted into the nef deletion site of SIVmac239Delta3 (Immune deficiency)

The goal of this study was to analyze the fate of exogenous genes inserted into the deleted nef of SIVmac239Δ3. Although it is well known that exogenous cellular genes such as IL-2, IL-12, and IFN-γ are deleted upon replication of the virus in cells, we hypothesized that exogenous genes of a viral origin may be more stable. Furthermore, the stability of these inserted genes may be a function of size, orientation, and the replication competence of the host virus in which they are inserted. A secondary goal of these experiments was to study the effects of certain exogenous genes on the replication of SIVmac239Δ3.; The experiments were limited to the in vitro study of two viral genes: HTLV-1 tax, and HHV-8 vMIP-II. The experimental plan involved inserting each gene, in sense and antisense transcriptional direction, into SIVmac239Δ3 and SIVmac239Δ3ΔLTR and to study gene expression and gene stability in cell culture. HHV-8 vMIP-II has only recently been described in the literature as a virokine capable of broad scale suppression of HIV-1 infection in human peripheral blood mononuclear cells via the blocking of chemokine co-receptors utilized by the virus. Concerning the study of the recently described vMIP-II , it was first necessary to derive the appropriate reagents as well as to address any antiviral properties in the SIV model. This was accomplished by first expressing vMIP-II in E. coli, deriving an antibody to vMIP-II, and studying the anti-SIV viral properties of vMIP-II in vitro.; The results reported here with tax and vMIP-II insertions into SIVmac239Δ3 and SIVmac239Δ3ΔLTR provide new insights into gene insertions and the role they may play in SIVmac239Δ3 attenuation and host immune modulation. Specifically, the assessment and characterization of the inserted gene stability as a function of orientation, size and expression offers important insights into our understanding of retroviral evolution and the development of a safe attenuated vaccine for HIV. Furthermore, the results provided by the work done with vMIP-II and tax insertions have elucidated the gene size and orientation requirements for designing stable mobilization competent gene therapy vectors to be utilized in gene therapy approaches to treating retroviral infection.