DNA fusion vaccine designed to induce cytotoxic T cell responses against defined peptide motifs: Implications for cancer vaccines
DNA fusion vaccine designed to induce cytotoxic T cell responses against defined peptide motifs: Implications for cancer vaccines
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DOI：
10.4049/jimmunol.167.3.1558
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发表时间：
2001-08-01
影响因子：
4.4
通讯作者：
Stevenson, FK
中科院分区：
文献类型：
--
作者：
Rice, J;Elliott, T;Stevenson, FK
DNA 疫苗接种提供了一种诱导对癌细胞进行免疫攻击的策略，但肿瘤抗原通常较弱。包含“外来”蛋白会增加免疫原性，我们之前发现破伤风毒素的片段 C (FrC) 与肿瘤 Ag 序列的融合可促进针对 B 细胞肿瘤的 Ab 和 CD4(+) 反应。对于 CTL 反应，使用完整的双结构域 FrC 可能不太有帮助，因为第二个结构域中已知的免疫原性 MHC I 类结合肽可能会与附着的肿瘤衍生表位竞争。因此，我们删除了第二个结构域，保留了 N 末端结构域，其中包含一个“通用”辅助表位。我们研究了放置在该结构域 C 末端的候选肽诱导 CTL 反应的能力。作为测试肽，我们将两个已知的 CTL 基序从第二个结构域重新定位到该位点。与天然 FrC 构建体相比，工程化构建体诱导了对每种肽的强烈 CTL 反应。诱导的 CTL 能够在体外和体内特异性杀死用 FrC 作为替代肿瘤 Ag 转染的肿瘤细胞。将结构域进一步还原为短辅助表位仅产生针对融合肽的微弱CTL反应，并且与含有第一个结构域的质粒混合的合成肽是无效的。单一 FrC 结构域肽疫苗设计还能够诱导高水平的针对癌胚 Ag 已知表位的 CTL。如果存在两个 FrC 结构域，则对肽的反应会受到抑制，这与免疫优势一致。这些原理和设计可能与通过 DNA 传递的癌症疫苗相关。
DNA vaccination offers a strategy to induce immune attack on cancer cells, but tumor Ags are often weak. Inclusion of a "foreign" protein increases immunogenicity, and we found previously that fusion of the fragment C (FrC) of tetanus toxin to the tumor Ag sequence promotes Ab and CD4(+) responses against B cell tumors. For CTL responses, use of the full two-domain FrC may be less helpful, because known immunogenic MHC class I-binding peptides in the second domain could compete with attached tumor-derived epitopes. Therefore, we removed the second domain, retaining the N-terminal domain, which contains a "universal" helper epitope. We investigated the ability to induce CTL responses of candidate peptides placed at the C terminus of this domain. As test peptides, we repositioned the two known CTL motifs from the second domain to this site. Strong CTL responses to each peptide were induced by the engineered construct, as compared with the native FrC construct. Induced CTLs were able to specifically kill tumor cells transfected with FrC as a surrogate tumor Ag both in vitro and in vivo. Further reduction of the domain to a short helper epitope generated only weak CTL responses against fused peptides, and synthetic peptides mixed with the plasmid containing the first domain were ineffective. The single FrC domain-peptide vaccine design also was able to induce high levels of CTLs against a known epitope from carcinoembryonic Ag. Response to peptide was suppressed if two FrC domains were present, consistent with immunodominance. These principles and designs may have relevance for cancer vaccines delivered via DNA.