Dendritic cell-lysosomal-associated membrane protein (LAMP) and LAMP-1-HIV-1 Gag chimeras have distinct cellular trafficking pathways and prime T and B cell responses to a diverse repertoire of epitopes
Dendritic cell-lysosomal-associated membrane protein (LAMP) and LAMP-1-HIV-1 Gag chimeras have distinct cellular trafficking pathways and prime T and B cell responses to a diverse repertoire of epitopes
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DOI：
10.4049/jimmunol.177.4.2265
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发表时间：
2006-08-15
影响因子：
4.4
通讯作者：
Marques, Ernesto T. A.
中科院分区：
文献类型：
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作者：
Arruda, Luciana B.;Sim, Del;Marques, Ernesto T. A.
Ag 处理是定义表位特异性免疫反应的关键步骤。在本研究中，HIV-1 p55Gag Ag 与溶酶体相关膜蛋白-1 (LAMP/gag) 或人树突细胞-LAMP (DC-LAMP/gag) 一起合成为 DNA 质粒，并用于免疫小鼠。对这两种嵌合体的细胞运输的分析表明，这两种分子与 MHC II 类分子共定位，但它们向内体/溶酶体区室的总体运输不同。 DNA 免疫后，两种嵌合体均在小鼠体内引发了有效的 Gag 特异性 T 和 B 细胞免疫反应，但其 IL-4 和 IgG1/IgG2a 反应存在显着差异。 DC-LAMP 嵌合体诱导了更强的 Th 1 型反应。 T 细胞对包含整个 p55gag 序列（15 个氨基酸肽，有 11 个残基重叠）的 122 个单独肽的反应的 ELISPOT 分析表明，用天然 gag、LAMP/gag 或 DC-LAMP/gag 进行 DNA 免疫可诱导对相同的免疫显性 CD4(+) 和 CD8(+) 肽的反应。然而，LAMP/gag 和 DC-LAMP/gag 质粒还引发了对 23 个额外的隐藏表位的显着反应，这些表位在用天然 gag DNA 免疫后未识别。这三种质粒诱导 T 细胞对总共 39 种不同的肽序列做出反应，其中 13 种是由所有三种 DNA 构建体诱导的。单独而言，DC-LAMP/gag 引发了最多样化的反应，对 35 种肽有特异性 T 细胞反应。此外，用LAMP/gag和DC-LAMP/gag嵌合体进行免疫也促进Ab分泌至数量增加的表位。这些数据表明，LAMP-1 和 DC-LAMP Ag 嵌合体遵循不同的运输途径，诱导不同的调节性免疫反应，并且能够呈现隐性表位。
Ag processing is a critical step in defining the repertoire of epitope-specific immune responses. In the present study, HIV-1 p55Gag Ag was synthesized as a DNA plasmid with either lysosomal-associated membrane protein-1 (LAMP/gag) or human dendritic cell-LAMP (DC-LAMP/gag) and used to immunize mice. Analysis of the cellular trafficking of these two chimeras demonstrated that both molecules colocalized with MHC class II molecules but differed in their overall trafficking to endosomal/lysosomal compartments. Following DNA immunization, both chimeras elicited potent Gag-specific T and B cell immune responses in mice but differ markedly in their IL-4 and IgG1/IgG2a responses. The DC-LAMP chimera induced a stronger Th type 1 response. ELISPOT analysis of T cell responses to 122 individual peptides encompassing the entire p55gag sequence (15-aa peptides overlapping by 11 residues) showed that DNA immunization with native gag, LAMP/gag, or DC-LAMP/gag induced responses to identical immunodominant CD4(+) and CD8(+) peptides. However, LAMP/gag and DC-LAMP/gag plasmids also elicited significant responses to 23 additional cryptic epitopes that were not recognized after immunization with native gag DNA. The three plasmids induced T cell responses to a total of 39 distinct peptide sequences, 13 of which were induced by all three DNA constructs. Individually, DC-LAMP/gag elicited the most diverse response, with a specific T cell response against 35 peptides. In addition, immunization with LAMP/gag and DC-LAMP/gag chimeras also promoted Ab secretion to an increased number of epitopes. These data indicate that LAMP-1 and DC-LAMP Ag chimeras follow different trafficking pathways, induce distinct modulatory immune responses, and are able to present cryptic epitopes.