GFP expression and mRNA transfer via exosome trafficking between non-immune cells. (A) Electron micrograph of vesicle release from a Jurkat cell. Cell preparations on UV activated carbon formvar 400 Mesh copper grids (Ted Pella 01 822-F), were imaged at 100 kV on a Philips CM120 TEM microscope. Images were collected on a Gatan 794CCD multiscan camera and converted into 8-bit gray-scale TIF, 28 000× magnification. OHSU-Electron Microscopy Resource (B) Jurkat cell with representative, exosome-sized, vesicles located at the limiting membrane at 7100× magnification. (C) Histogram representation of green fluorescent protein (GFP) expression by Jurkat cells (Jurkat-GFP) after replication deficient retrovirus vector transduction (vesicular stomatitis virus G protein pseudotype, MOI 1, GFP expression cassette) and non-transduced control (Jurkat). (D) Overlay histogram demonstrating GFP expression in murine whole bone marrow cells (mWBM) 48 hours after transwell (0.4 μm pore) exposure to Jurkat-GFP derived vesicles (Jurkat-GFP-V) or media control (Media over mWBM). Vesicles (V) were isolated from culture media by differential centrifugation at 300g × 10 minutes, 2 000g × 15 minutes, 10 000g × 20 minutes, and at 100 000g × 2 hours. The pellet was washed, ultracentrifuged at 100 000g for 2 hours and resuspended in PBS. (E) Reverse transcription PCR analysis indicating the presence or absence of GFP sequence in mWBM cells after indicated coculture conditions: 48-hour transwell (TW), concentrated vesicles (V) or vesicle rich media (VRM) from Jurkat-GFP cells versus media control. RNA was extracted using RNeasy (QIAGEN). Complementary DNA was synthesized using the SuperScript III First Strand Synthesis Kit (Invitrogen) with oligo-dT priming followed by PCR. (F) Detection of GFP transcripts in non-mobilized normal human CD34⁺ (hCD34) cells (Stem Cell Technologies). Culture condition, sample handling and reverse transcription PCR analysis as in panel E. Experiments were repeated with similar results.