Double immunofluorescence staining - detection of Bt18 binding to CEM-SS cells and detection of GAPDH expression in CEM-SS cells. (400× magnification). (Scale bar = 50 μm). (A) Binding of Bt18 on CEM-SS cells detected using a Texas Red filter. (B) Nucleus of CEM-SS cells detected using a Hoechst filter. (C) Superimposed images of (A) and (B). (D) Detection of GAPDH expression CEM-SS cells using FITC filter. (E) Nucleus of CEM-SS cells detected using a Hoechst filter. (F) Superimposed images of (D) and (E).