In this model, expression of green fluorescent protein (GFP) driven by the SV40 promoter waned within 4 days of infection, but viral DNA was maintained, and full virus reactivation was shown after stimulation of HPCs with granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) and coculture on permissive fibroblasts. This evidence concerns the gene CSF2 and infection.