We have investigated the regulation of host cell genes by HIV infection of primary human macrophages. Using commercial gene grids we have screened in parallel primary human macrophages either infected with HIV or uninfected. From these we have identified hundreds of genes which appear to be regulated by HIV infection. We are now confirming these by """"""""TAQ-Man"""""""" PCR analysis, focusing first on genes which are involved in apoptosis and subsequently on genes involved in intracellular signalling. Currently we are doing similar studies on macrophages treated with HIV tat protein. We have recently published interesting findings concerning genes involved in protecting macrophages from HIV-induced cell death and concerning upregulation by HIV or macrophage genes responsible for killing neighboring, uninfected cells during HIV infection. Further genes involved in programmed cel death are being studied with respect to HIV infection. In other studies, we are investigating the interactions between Dengue virus (as a model of West NIle Virus) and HIV. Both infect macrophages in humans and we are determining whether coinfection of macrophages is synergistic.