| Summary: | 碩士 === 國立成功大學 === 醫事技術學系 === 92 === Lactoferrin (LF) is an iron binding glycoprotein present in some biological fluids of mammals, such as milk, saliva, and mucous secretions. The well-studied function of LF is responsible for the transportation of metals in plasma. However, recent studies have revealed that LF plays an important role in non-specific immune system against many bacterial infection as well as viral agents. In this study we have investigated the antiviral activities of LF against enterovirus71 (EV71) which causes hand, food and mouth disease, pulmonary edema and encephalomyelitis as well as dengue virus (DV), which is the most important arthropod-borne human pathogen, and results in severe dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). We found that the infection of EV71 and DV can be inhibited by different doses of bovine LF (IC50 is 34.5 �慊/ml and 67.6 �慊/ml, respectively). LF not only could prevent EV71 and DV infection, but could also decrease virus titer when target cells were treated with LF at IC90 dose at post-infection stage. Using target cell coated-96 wells plate、IFA and immunoprecipitatioin, we found LF could bind directly to target cells. We also used virus and VP1 of EV71 coated-96 wells plate and competition assay, and found LF could also bind directly to virus. Furthermore, using Far-Western blot, we found that LF can bind to VP1 caspid protein of EV71 and the E protein of DV, both proteins are account for the binding of the viruses to the cells. In addition to no-cytotoxicity to the target cell, LF can induce IFN-���n expression of host cell. Not only in vitro, LF can also prevent mice from EV71 infection. Therefore, the antiviral as well as immunostimulatory effects of LF make it a promising candidate for the treatment of diseases induced by EV71 and DV.
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