Department of Microbiology and Immunology, Nanjing Medical University, Nanjing 210029, China.
Cell Mol Immunol. 2009 Dec;6(6):423-31. doi: 10.1038/cmi.2009.54.
Epstein-Barr virus infection is strongly associated with a number of malignancies. The EBV latent membrane protein 2A has been implicated as one of the most attractive candidates for immunotherapy of related malignancies. In previous studies, the T cell epitopes of LMP2A have been identified systematically. However, the epitope-based vaccine generally meets inefficient immunogenicity when used in vivo directly, which could be overcome by combination with appropriate adjuvants. Heat shock protein is a natural chaperon, which is able to activate the classical major histocompatibility complex class I antigen-processing pathway (cross-presentation). In this study, a minigene encoding LMP2A(356-364) (FLYALALLL) was genetically fused to the carboxy-terminal of mycobacterial heat shock protein 70. The epitope fusion protein was expressed and purified, and the cross-presentation of LMP2A(356-364) by monocyte-derived dendritic cells pulsed with the epitope fusion protein was evaluated. Results showed that the epitope fusion protein-pulsed mDCs were much more efficient than the single peptide-pulsed mDCs on CTL activation. Immunization of HLA-A2.1 transgenic mice with MtHsp70-LMP2A(356-364) generated peptide specific CTL more effectively than a single peptide plus incomplete Freund's adjuvant (IFA). Growth of LMP2A expressing B16 melanoma tumor cells was suppressed in the vaccinated groups. Our results suggested that MtHsp70-LMP2A(356-364) fusion protein was more effective than the CD8(+) T cell epitope alone on anti-tumor immunity. As a result, the MtHsp70-LMP2A(356-364) fusion protein is considered to be a promising candidate vaccine for EBV related malignancies.
EB 病毒感染与许多恶性肿瘤密切相关。EBV 潜伏膜蛋白 2A 已被认为是相关恶性肿瘤免疫治疗最有吸引力的候选者之一。在以前的研究中，已经系统地鉴定了 LMP2A 的 T 细胞表位。然而，基于表位的疫苗在体内直接使用时通常具有低效的免疫原性，这可以通过与适当的佐剂结合来克服。热休克蛋白是一种天然伴侣，能够激活经典的主要组织相容性复合物 I 抗原加工途径（交叉呈递）。在这项研究中，编码 LMP2A(356-364)（FLYALALLL）的小基因与分枝杆菌热休克蛋白 70 的羧基末端进行了基因融合。表达并纯化了融合蛋白，并评估了融合蛋白脉冲单核细胞衍生的树突状细胞（mDC）的 LMP2A(356-364)的交叉呈递。结果表明，与单一肽脉冲 mDC 相比，融合蛋白脉冲 mDC 对 CTL 激活的效率更高。用 MtHsp70-LMP2A(356-364)免疫 HLA-A2.1 转基因小鼠比单一肽加不完全弗氏佐剂（IFA）更有效地产生肽特异性 CTL。在接种组中，表达 LMP2A 的 B16 黑色素瘤肿瘤细胞的生长受到抑制。我们的结果表明，与单一 CD8+T 细胞表位相比，MtHsp70-LMP2A(356-364)融合蛋白在抗肿瘤免疫方面更有效。因此，MtHsp70-LMP2A(356-364)融合蛋白被认为是 EBV 相关恶性肿瘤的一种有前途的候选疫苗。
