ARP-1819 was selected for low basal luciferase activity, HIV infectability, high responsiveness totat expression, and high responsiveness to T-cell activation signals. Conditions can be established for quantitative analysis of LTR(HIV-1)-luciferase response to each of these conditions. A 10-1000-fold increase in luciferase activity can be achieved after transfection or infection of 1G5 withtat-expressing vectors or HIV. Equivalent levels of expression have also been detected after stimulation with T cell mitogens and stimulating environmental conditions. When used in conjunction with a tat-expressing vector, 1G5 provides a system for testing potential anti-tat therapies without the use of live HIV.

Growth Characteristics:   This cell line can be difficult to grow. Viability tends to start low and will drop a few days after initial culture. Keep cells slightly crowded until the culture recovers. This may take a week or more.  1G5 cells should be maintained at 1 × 10⁶ cells per mL. Doubling time is approximately 24 hours. Split 1:10 every five days. The cells grow in suspension as single cells or small clumps. The suggested medium for 1G5 cells is RPMI with 10% fetal bovine serum; however, 1G5 cells have also been grown in RPMI with 5% fetal bovine serum and DMEM with 10% fetal bovine serum without appreciable change in their characteristics.   

Colony Morphology:   Characteristic T cell appearance; round, refractile with smooth edges.

Growth Medium:   RPMI 1640 supplemented with 10% fetal bovine serum