Effect of IL-1β on initial infection and growth of GFP-CMV in HS-27a stromal cells. Cells were cultured in the presence or absence of 2 ng/mL of IL-1β for 1 day and then infected with GFP-CMV at an MOI of 0 to 100. The cultures were continued in the presence or absence of IL-1β for 13 days. Fluorescence intensity of GFP was measured using a fluorocytometer as described. (A) shows that comparable levels of GFP for control and IL-1β–treated groups, regardless of MOI, were detected 1 and 2 days after infection. (B) shows a significant difference in GFP intensity between control and IL-1β–treated cultures after day 10.