Figure 1.

Generation and confirmation of PIP-expressing 4T1 cells. Lentivirus encoding the mouse PIP cDNA–eGFP construct was incubated with 4T1 cells for overnight incubation. Contour plots show the percentages of GFP expressing 4T1 cells for un-transduced cells (A) and transduced cells before (B) and after sorting (C) by flow cytometry. Western blot analysis using polyclonal rabbit anti-mouse PIP antibody was performed on 4T1 cell lysate (D) and cell culture media (E) as described in the Materials and Methods section. Mouse saliva was used as a positive control for PIP.