A NEW REPORTER CELL-LINE TO MONITOR HIV-INFECTION AND DRUG SUSCEPTIBILITY IN-VITRO

Determination of HIV infectivity in vitro and its inhibition by antire troviral drugs by monitoring reduction of production of p24 antigen is expensive and time consuming. Such assays also do not allow accurate quantitation of the number of infected cells over time, To develop a s imple, rapid, and direct method for monitoring HIV infection, we gener ated a stable T-cell line (GEM) containing a plasmid encoding the gree n fluorescent protein (humanized S65T GFP) driven by the HIV-I long te rminal repeat, Clones were selected that displayed low constitutive ba ckground fluorescence, but a high level of GFP expression upon infecti on with HIV, HIV-1 infection induced a 100- to 1,000-fold increase in relative fluorescence of cells over 2 to 4 days as monitored by fluore scence microscopy, cytofluorimetry, and flow cytometry. Addition of in hibitors of reverse transcriptase, protease, and other targets at diff erent multiplicities of infection permitted the accurate determination of drug susceptibility, This technique also permitted quantitation of infectivity of viral preparations by assessment of number of cells in fected in the first round of infection, In conclusion, the CEM-GFP rep orter cell line provides a simple, rapid, and direct method for monito ring HIV infectivity titers and antiretroviral drug susceptibility of syncytium-inducing strains.