English: Human astrocytes or HEK293 cells were transfected with IL-1β/GFP or GFP expression plasmids as described in the Materials and Methods. (A, B) Fluorescence microscopy at 24 h after transfection reveals that control GFP vector but not IL-1/GFP vector-transfected astrocytes show green fluorescence. In contrast, HEK293 cells showed fluorescence in both conditions. (C) Western blot analysis of HEK293 cells (left) and human astrocytes (right) transfected with none (control), GFP plasmid (GFP), or IL-1 plasmid (IL-1/GFP). Incubation with anti-IL-1β antibody shows positive bands only in IL-1/GFP-transfected HEK cells and not in human astrocytes. The last lane (Std.) is a positive control (17 kDa recombinant IL-1β).