Saturation curve and specificity of the tristetraprolin (TTP) polyclonal antibody. Results are shown as milliequivalents of soluble fluorescein ± SE and are representative of two separate experiments. (a) Nontransfected and transfected 293 cells were stained with increasing concentrations of the rabbit-derived anti-TTP antibody, or a rabbit IgG control, and then with secondary FITC-conjugated donkey antirabbit IgG. (b) Specificity was demonstrated by introducing the TTP peptide at 10 and 50 times the concentration of the antibody used. All bars derive from the transfected phenotype. (c) Confocal microscopy of cells stained as described for TTP and nuclear staining with propidium iodide. Ab = antibodies; MESF = milliequivalents of soluble fluorescein; SE = standard error of the mean.