This invention provides a DNA construct that can be useful for both diagnostics and AIDS therapeutics. The construct can be incorporated into a retrovirus or into a cell line. This construct mediates the expression of a selected gene in the presence of HIV replication, but is silent in the absence of HIV. The cell line with the incorporated construct can be used as an indicator line for the presence of replication-competent HIV. The virus containing the construct can be used to co-infect a population of HIV-infected cells. If the construct-encoded gene is a reporter, it would specifically identify cells that are infected with HIV. If the construct-encoded gene is a cytotoxin, it would specifically kill cells that are HIV-infected. This invention may offer a novel approach to HIV elimination, as well as detection of HIV infected cells or the presence of cell-free infectious HIV.