Liposome-Coupled Antigens Are Internalized by Antigen-Presenting Cells via Pinocytosis and Cross-Presented to CD8+ T Cells
Liposome-Coupled Antigens Are Internalized by Antigen-Presenting Cells via Pinocytosis and Cross-Presented to CD8+ T Cells
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DOI：
10.1371/journal.pone.0015225
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发表时间：
2010-12-17
期刊：
影响因子：
3.7
通讯作者：
Uchida, Tetsuya
中科院分区：
文献类型：
--
作者：
Tanaka, Yuriko;Taneichi, Maiko;Uchida, Tetsuya
我们以前已经证明，化学偶联到由不饱和脂肪酸组成的脂质体表面的抗原通过抗原呈递细胞（APC）交叉呈递给CD 8（+）T细胞，并且该过程导致诱导抗原特异性细胞毒性T淋巴细胞。本研究探讨了脂质体偶联抗原通过APCs交叉提呈给CD 8（+）T细胞的机制。共聚焦激光扫描显微镜分析表明，抗原耦合到表面的不饱和脂肪酸为基础的脂质体接受处理在MHC I类和II类室，而大多数的抗原耦合到表面的饱和脂肪酸为基础的脂质体接受处理在II类室。此外，流式细胞术分析表明，抗原偶联到不饱和脂肪酸脂质体的表面被APC，即使在4摄氏度的环境中，这是不正确的饱和脂肪酸脂质体。当在抗原脉冲前向培养的APCs中加入分别抑制APCs的胞饮和吞噬作用的两种抑制剂DMA和细胞松弛素B时，DMA而不是细胞松弛素B显著降低脂质体偶联抗原的摄取。使用共聚焦激光扫描显微镜对脂质体抗原的细胞内运输的进一步分析显示，由APC摄取的脂质体偶联抗原的一部分被递送到溶酶体隔室。与APC对抗原摄取的减少一致，DMA显著抑制APC的抗原呈递，并导致抗原特异性CD 8（+）T细胞产生IFN-γ的减少。这些结果表明，偶联到由不饱和脂肪酸组成的脂质体表面的抗原可能被APC胞饮，加载到I类MHC加工途径上，并呈递给CD 8（+）T细胞。因此，预期这些脂质体偶联抗原可用于开发诱导细胞免疫的疫苗。
We have previously demonstrated that antigens chemically coupled to the surface of liposomes consisting of unsaturated fatty acids were cross-presented by antigen-presenting cells (APCs) to CD8(+) T cells, and that this process resulted in the induction of antigen-specific cytotoxic T lymphocytes. In the present study, the mechanism by which the liposome-coupled antigens were cross-presented to CD8(+) T cells by APCs was investigated. Confocal laser scanning microscopic analysis demonstrated that antigens coupled to the surface of unsaturated-fatty-acid-based liposomes received processing at both MHC class I and class II compartments, while most of the antigens coupled to the surface of saturated-fatty-acid-based liposomes received processing at the class II compartment. In addition, flow cytometric analysis demonstrated that antigens coupled to the surface of unsaturated-fatty-acid-liposomes were taken up by APCs even in a 4 degrees C environment; this was not true of saturated-fatty-acid-liposomes. When two kinds of inhibitors, dimethylamiloride (DMA) and cytochalasin B, which inhibit pinocytosis and phagocytosis by APCs, respectively, were added to the culture of APCs prior to the antigen pulse, DMA but not cytochalasin B significantly reduced uptake of liposome-coupled antigens. Further analysis of intracellular trafficking of liposomal antigens using confocal laser scanning microscopy revealed that a portion of liposome-coupled antigens taken up by APCs were delivered to the lysosome compartment. In agreement with the reduction of antigen uptake by APCs, antigen presentation by APCs was significantly inhibited by DMA, and resulted in the reduction of IFN-gamma production by antigen-specific CD8(+) T cells. These results suggest that antigens coupled to the surface of liposomes consisting of unsaturated fatty acids might be pinocytosed by APCs, loaded onto the class I MHC processing pathway, and presented to CD8(+) T cells. Thus, these liposome-coupled antigens are expected to be applicable for the development of vaccines that induce cellular immunity.