Effects of CM on subnuclear distribution and expression of C/EBPβ in macrophage cell lines. C/EBPβ expression and localization was assessed by indirect immunofluorescence in the macrophage cell lines P388D1(IL1) (A through D, K through R), IC-21 (E, F, I, and J), or T4.3 (G and H). Cells were grown in fresh medium for 16 hours in the absence (A, B, E, G, and K through N) or presence (C, D, F, H, I, J, and O through R) of CM. C/EBPβ was visualized using a peptide antibody specific for the N terminus of C/EBPβ. (B, D, L, N, P, and R) Show DAPI staining patterns for the corresponding immunofluorescent fields in the left-hand panels. Note that the punctate DAPI pattern is unchanged by treatment with CM. (I and J) Show CM-treated IC-21 cells stained with the C/EBPβ antibody in the absence (I) or presence (J) of the synthetic peptide used to generate the antiserum, and (K through R) are high magnification confocal images of individual cells. Fluorescent images were recorded using a Nikon Microphot-FXA microscope (Nikon, Tokyo, Japan) (A through D) or a Zeiss LSM 310 confocal microscope (Zeiss, Thornwood, NY) (E through R).