Activating mechanism of Immunomodulatory Protein from Anoectochius formosanus (IPAF) on immune cells

• Main Authors: Ju-Chun Hsu, 許如君
• Other Authors: 許輔
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/06377654483210925949

碩士 === 國立臺灣大學 === 園藝學研究所 === 93 === Abstract IPAF (immunomodulatory protein from Anoectochilus formosanus Hayata) was purified from Anoectochilus formosanus Hayata by 30% saturation of ammonium sulfate precipitation. SDS-PAGE analysis showed that IPAF has a molecular weight of 14 kDa and isoelectric focusing electrophoresis revealed the isoelectric point of IPAF was 5.4. Culturing RAW 264.7 macrophages with IPAF in vitro showed that IPAF could activate the cells and then increase nitric oxide, TNF-α and IL-1β production. Moreover, IPAF also stimulated the proliferation of murine splenocytes and increased their IFN-γ secretion, but did not result in IL-4 production. However, the cell depletion test demonstrated that IPAF increased the B cell proliferation without T cells existing. These results suggested that IPAF was a thymus-independent antigen. Peritoneal cells from C57BL/10ScN mice, which have a null mutation in TLR4 (TLR4-/-), were hyporesponsive in TNF-α secretion to both LPS and IPAF, suggesting that LPS and IPAF may share a same signaling pathway involving TLR4. On the other hand, IPAF could increase TLR4-/- B cells proliferation. Therefore, we propose that IPAF might be not involved in TLR4 signaling pathway and have another signaling pathway in B cell proliferation. Taking together, this study clearly demonstrated that IPAF, which activated B cells and also activated macrophages through TLR4, is an immune stimulus and could be helpful to strength the immunity of its host.