α-半乳糖神經醯胺嵌合微脂粒作為具標靶性及免疫刺激性抗原載體於癌症免疫治療之研究

The Evaluation of α-Galactosylceramide Incorporated Liposomes as Targeted and Immunostimulatory Carriers of Antigen for Cancer Immunotherapy

江秉倫(Ping-Lun Jiang)

指導教授 ： 黃義侑

國立臺灣大學/工學院/醫學工程學研究所/博士(2015年)

https://doi.org/10.6342/NTU.2015.10043

摘要

癌症是一種嚴重的疾病，其特徵為異常細胞的生長或轉移，並可能侵入或擴散到身體的其他部位，是目前國人十大死因之首。雖然目前許多臨床療法應用於治療癌症，然而這些治療方式往往引起各種嚴重的副作用，同時在一些特定的癌症類型中，無法達到有效的治療效果，因而降低了病患的存活率。癌症免疫療法是利用誘發個人的免疫系統，辨識並有效破壞癌細胞。多年來，研究者認為若成功誘發患者自身的免疫系統或合併其他治療方式，能有效治療癌症並能顯著改善癌症患者的存活率，而不會產生嚴重的副作用。因此，如何有效地誘導免疫反應以治療各種類型的癌症是一個極其重要且值得深入研究的議題。
已有研究指出α-半乳糖神經醯胺為治療腫瘤一種有效的疫苗佐劑。在本研究中，製備過程中親脂性的α-半乳糖神經醯胺嵌入微脂粒之脂質雙層，並展露其親水性半乳糖分子於微脂粒體的外表面。卵清蛋白則包覆於微脂粒內部，製備成α-半乳糖神經醯胺嵌合微脂粒，並探討α-半乳糖神經醯胺嵌合微脂粒作為具有樹突狀細胞標靶性與免疫調節性黏膜疫苗之潛力。
將各組別微脂粒的粒徑控制在大約1000至1100奈米的範圍，其卵清蛋白包覆率約為30-40％。結果證實，α-半乳糖神經醯胺嵌合微脂粒在體外試驗中能有效地被小鼠骨髓樹突狀細胞胞吞而有效地進行抗原傳遞，使樹突狀細胞表現高量的成熟標記物，包括CD80，CD86和MHC II類分子，以及誘導促炎細胞因子的分泌量。而在動物實驗中，α-半乳糖神經醯胺嵌合微脂粒也能有效地被鼻咽相關淋巴組織中樹突狀細胞所吞。進一步的，C57BL/6小鼠以經鼻免疫方式給予包覆卵清蛋白的α-半乳糖神經醯胺嵌合微脂粒疫苗，觀察到其血清中有高量的卵清蛋白特異性IgG抗體，以及鼻腔沖洗液中分泌型IgA抗體之生成量。而在給予α-半乳糖神經醯胺嵌合微脂粒免疫的小鼠組別之脾細胞經由體外以卵清蛋白再刺激情況下， 細胞激素IFN-γ和IL-4的生成量有明顯增加，同時可分泌IFN-γ的CD8+細胞之數量也有明顯增加的情形。此外，經由α-半乳糖神經醯胺嵌合微脂粒免疫的小鼠組別，完全抑制了EG7腫瘤細胞的生長，提供了良好的預防效果。這些結果顯示，α-半乳糖神經醯胺嵌合微脂粒具有良好的抗原傳遞與免疫調節能力，可誘發有效的免疫反應以對抗腫瘤細胞之生長，具備進一步應用於臨床抗腫瘤用途之潛力。

關鍵字

α-半乳糖神經醯 ； 標靶性微脂粒 ； 抗原傳遞 ； 黏膜免疫 ； 癌症疫苗

並列摘要

Cancer is a terrible disease characterized by abnormal cell growth and metastasis, which is the potential to invade or spread to other parts of the body. Although many clinical therapies are used to kill the cancer cells, these therapies usually cause a variety of side effects and show low survival in some particular type of cancer. Cancer immunotherapy is the use of one person’s immune system to treat or destroy cancer. Over the years, the researchers believe that successful stimulation of the patient’s own immune system are able to eliminate cancer and are able to significantly improve the survival rate of cancer patients without producing serious side effects. Therefore, how to induce effective immune responses to treat various types of cancer has been an extremely important issue.
Alpha-Galactosylceramide is a potent vaccine adjuvant in protecting against tumors. In this study, α-GalCer was incorporated into lipid-bilayer of liposome and exposed galactose molecules on the outer surface of liposome. Ovalbumin (OVA) was then encapsulated into α-GalCer incorporated liposomes. We evaluate whether α-GalCer incorporated liposomes could act as an effective DC-targeted mucosal vaccine that could facilitate antigen delivery familiar to galactosylated liposomes we have published. The immunoregulatory effects of α-GalCer incorporated liposomes were also evaluated.
The particle sizes of each liposome formulation were controlled to are approximately 1000-1100 nm and OVA encapsulation efficiencies are approximately 30-40%. We demonstrated that α-GalCer incorporated liposomes effectively facilitated antigen uptake by mouse bone-marrow derived dendritic cells (BMDCs) in vitro, led to higher expression of maturation markers, including CD80, CD86 and MHC II, and induced higher production of pro-inflammatory cytokines. In vivo uptake of α-GalCer incorporated liposomes by DCs in nasopharynx-associated lymphoid tissue (NALT) showed the similar results. C57BL/6 mice immunized intranasally with OVA-encapsulated α-GalCer incorporated liposomes produced high levels of OVA-specific IgG antibodies in their serum and secretory-IgA (s-IgA) in nasal wash fluid. Spleen cells from mice receiving α-GalCer incorporated liposomes were re-stimulated with OVA and showed significantly augmented levels of IFN-γ and IL-4, and increase number of IFN-γ producing CD8+ cells. In addition, intranasal administration of α-GalCer incorporated liposomes resulted in complete protection against EG7 tumor challenge in C57BL/6 mice. Taken together, these results indicate that nasal administration of α-GalCer incorporated liposomes mediates the development of an effective immunity against tumors and might be useful for further clinical anti-tumoral applications.

並列關鍵字

Alpha-Galactosylceramide ； Targeted liposome ； Antigen delivery ； Mucosal immunity ； Cancer vaccine

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