| Summary: | 碩士 === 長庚大學 === 基礎醫學研究所 === 92 === Abstract
EBV-encoded oncogene LMP1 has been known to be highly associated with several malignancies. LMP1 isolated from Taiwan’s NPC patient biopsy (NLMP1) is different from the gene originally identified in Burkitt’s lymphoma (BLMP1) by 10 amino acid deletion at C-terminal end and multiple point mutations throughout the gene. In addition, it has been documented that NLMP1 oncoprotien exerts longer half life, higher tumorigenicity and no immunogenicity. However, by an EBV-NLMP1 tumor animal model established in this laboratory, we have demonstrated irradiated NLMP1 tumor cells can induce a strong T cell-mediated anti-tumor immunity. A CD8+ T cell epitope of NLMP1 (Np) has also been identified. Recently, many reports illustrated the interplay among T, NK and dendritic cells (DC). And DC technology in CD4+ or CD8+ T cell activation has also been developed. Here, to test whether NLMP1 itself can be presented by DC to activate CTL response, the system that DC infected with recombinant adenovirus carrying NLMP1 (AdNLMP1) or pulsed with Np was established. Firstly, we showed the expression of AdNLMP1-derived LMP1 protein was transient for several days after infection. Secondly, the infectivity of AdNLMP1 to DC from of BALB/c mice is ~40% at MOI 250. Thirdly, CD40, CD80, CD86, MHC I and MHC II expression on DC was positive after viral infection. Fourthly, the production of IL-6 is also elevated after induction. In subsequent in vitro and ex vivo experiments, AdNLMP1-infected or Np-pulsed DC (AdNLMP1-DC or Np-DC) exhibited the ability to activate anti-NLMP1 tumor CTL. Furthermore, Np-DC immunized mice were challenged with NLMP1 tumor. A significant delayed tumor growth was found. In addition, to understand the immune network underlying the tumor prevention, in vivo antibody depletion experiment upon immunization revealed that CD4+ T and NK cells are also involved in the anti-tumor immunity. Altogether, our results suggest that a NLMP1-based DC vaccine can be designed to achieve a full scale of anti-NLMP1 immunity in vivo consisting CD4+ T, CD8+ T and NK response.
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