FIG 6.

FMLV-IL-1β causes prolonged infection and immune activation in BALB/c mice. (A) BALB/c mice were infected with FMLV or FMLV-IL-1β. At 5 weeks postinfection, spleens were dissected, and assayed for focus-forming units (FFU) by plating splenocytes on Mus dunni cells, followed by a focus-forming assay. Assay results were used to calculate the FFU per spleen in each infected mouse. ND, not detected. (B) The weights of spleens from BALB/c mice at 5 weeks postinfection were measured (right). Representative spleens are shown on the left. (C) Splenocytes were analyzed for immune cell expression of activation markers by flow cytometry. Each bar represents the average for five mice. Asterisks indicate P values of <0.05 (t test). Error bars indicate the standard deviations of the data set.