| Summary: | 碩士 === 國防醫學院 === 微生物及免疫學研究所 === 103 === Y. pestis is a Gram-negative, rod-shaped coccobacillus, a facultative anaerobic bacterium that can infect humans and animals. Y. pestis antigen fraction 1, F1, is the surface polymer composed of subunits. F1 has been implicated to virulent of Y. pestis. That is most important antigen produced by the bacterium at normal human body temperature. However, we will dependent the F1 to develop the phage as higher sensitivity probes for Y.pestis infection test. Phage Display is a method which discovers the peptide sequences for objective proteins. It could be used for biomedical applications, antibacterial reagents, drug delivery vehicles, tissue engineering materials, etc. In our plan, we may find out some phages having specific affinity for the protein of Yersinia pestis, F1. We will combine the phage and some chemical or physical markers, for example, ionic colloidal gold and quantum dots. In the future, we will screen different bacterial toxin antigens by Phage Display continually, and base on the data from peptide sequencing analysis to design some host cell receptor related studies.
On the other hand, the two N-terminal a-helices of the Yersinia protein YopM can function as cell-penetrating peptides (CPPs) which have the ability to cross cellular membranes, either alone or in association with bioactive cargo. Therefore, we exploited the CPP from YopM as a tool for anthrax lethal factor intracellular delivery, and led to understanding and evaluating the cytotoxic function of LF without the need for endocytosis with PA. This CPP-antigen coupling is achieved via recombinant fusion constructs produced by baculovirus-based expression system. Furthermore, the delivery and uptake of immunogenic antigens by APC, subsequent processing and presentation are all fundamental for induction of an effective immune response. Historically, peptide and protein-based vaccines incorporating cytotoxic T lymphocyte (CTL) epitopes have limited efficacy, as APCs are not efficient in the uptake and processing of exogenous antigens via the MHC class I pathway. Thus, we utilized the CPP from YopM provide an effective means to facilitate intracellular delivery of antigens and observe a CTL response.
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