PC12 cells were transiently transfected with the p75NTR-specific ER retained intrabodies or αphOx-KDEL. Four days after transfection, the p75NTR surface expressions were determined with mouse anti-p75NTR mAb (MLR2, 1∶200) followed by goat anti-mouse IgG F(ab′)2 fragment APC conjugated (1∶200, B, D, F, H, and J). Cells stained with secondary antibody alone were served as control (A, C, E, G, and I). Overlay analysis for the p75NTR surface expression is shown in PC12 cells (K). The blue histograms represent the p75NTR surface expression of the PC12 cells expressing the p75NTR-specific ER retained intrabodies. The white histograms represent the p75NTR surface expression of the PC12 cells expressing the control αphOx-KDEL. The efficiency of knockdown p75NTR surface expression is indicated in percent. The picture of SH325-G7-KDEL is also shown in Figure 7 as 4 day time point result.