Selective killing of HIV-1-positive macrophages and T cells by the Rev-dependent lentivirus carrying anthrolysin O from Bacillus anthracis

We demonstrate that in the Rev-dependent lentiviral vector, anlO expression is exclusively dependent on Rev, a unique HIV-1 protein present only in infected cells. Intracellular expression and oligomerization of AnlO result in membrane pore formation and cytolysis. We have further overcome a technical hurdle in producing a Revdependent AnlO lentivirus, through the use of β-cyclodextrin derivatives to inhibit direct killing of producer cells by AnlO. Using HIV-1-infected macrophages and T cells as a model, we demonstrate that this Rev-dependent AnlO lentivirus diminishes HIV-1- positive cells.The Rev-dependent lentiviral vector has demonstrated its specificity in targeting persistently infected cells. The choice of anlO as the first suicidal gene tested in this vector is based on its cytolytic activity in macrophages and T cells. We conclude that Rev-regulated expression of suicidal genes in HIV-1-positive cells is possible, although future in vivo delivery of this system needs to address numerous safety issues.The success of highly active antiretroviral therapy (HAART), marked by the drastic reduction of plasma viremia and restoration of certain immune functions [1-3], led initially to speculation of disease eradication in 2 to 3 years [4,5]. This original optimism was soon dampened by the realization that persistence of viral reservoirs would make it extremely difficult, if not impossible, to eradicate HIV-1 [6-11]. Further identification and characterization of these reservoirs have highlighted the limitations of HAART. It has become evident that with drug cessation, viral loads return to pre-HAART levels [12,13]. With no alternative approaches in use to specifically target cells harboring the virus, it would take an estimated 60 years for some of these reservoirs to naturally decay [14].The primary reservoirs of HIV-1 include resting CD4 T cells and cells of the macrophage lineage. Both are the natural targets of HIV-1. It has been shown that in vitro stimulation