IL-1Ra production by human synoviocytes after static transduction for extended periods. Monolayer cultures of synoviocytes from five different patients with RA were transduced statically in duplicate with standard titer MFG-IRAP for the indicated lengths of time. Supernatants were changed every 24 h, until transductions were completed for all cultures. The cells were then washed, given complete media, and incubated for a further 48 h. At this time, media were harvested and IL-1Ra content was determined. Values are means ± SD. IL-1Ra production increased significantly (P < 0.05) when the time of transduction was increased from 24 to 48 h and from 48 to 72 h.