Purification and Characterization of Transforming growth factor-β1 from Human Platelets

Purification and Characterization of Transforming growth factor-β1 from Human Platelets

Transforming growth factor-β1 (TGF-β1 ) has potential for therapeutic use in common clinical conditions for which there are no adequate pharmacological agents. However, invivo studies using TGF-β1 were hindered by high price of this cytokine. As a first steo towards large scale purification of TGF-β1 , it was purified in a small scale (10 unit platelets) from human platelets by four purification steps: platelet extraction, gel filtration, cation exchange chromatography, and reversed phased high performance liquid chromatography (HPLC). A single protein band with a molecular weight of 25 Kd corresponding to purchased TGF-β1 (R&D Systems) was confirmed by silver staining after SDS-polyacrylamide gel electrophoresis (SDS-PAGE) of eiuant from reversed phase HPLC. Recovery (%) of each step was about 50~60%, resulting in the final recovery of 20% based on the detection by a sandwich ELISA. Approximately, 3.7 ㎍ of purified TGF-β1 was obtained from 18 ㎍ of platelet extracts. This result was confirmed by receptor(TGF-β1 type Ⅱ) ELISA and bioassay using a mink lung epithelial cell line(MV1LU). Further, in vitro characterization study showed that purified TGF-β1 inhibits G1/S transition of LPS-activated murine spleen B cells and increases surface lgA expression by the same cell population, which are typical activities of TGF-β1 in B cell diffetentiation. Taken together, the results from the present study reveals that purified TGF-β1 is fully biologically active and our purification methodology could be useful to obtain a large scale of recombinant TGF-β1 in the future. Korean J. Immunol. 20 1:1~8, 1998 Key Words: Human platelet, TGF-β1, ELISA, Bioassay, Cell cycle, lgA