Provenzano Maurizio, Selleri Silvia, Jin Ping, Wang Ena, Werden Rosemary, Slezak Stephanie, Adams Sharon D, Panelli Monica C, Leitman Susan F, Stroncek David F, Marincola Francesco M
Immune Oncology Section, Department of Surgery, University Hospital ZLF, Hebelstrasse 20, 4031 Basel, Switzerland.
Cancer Immunol Immunother. 2007 Jul;56(7):1047-63. doi: 10.1007/s00262-006-0246-3. Epub 2006 Nov 24.
Latent membrane protein (LMP)-2 is one of the Epstein-Barr virus (EBV)-encoded proteins consistently expressed by nasopharyngeal carcinoma (NPC). EBV-transformed lymphoblastoid cell lines (LCL) have been used in patients with NPC to induce LMP-2-recognizing T cell lines which have been in turn utilized for protein-wide mapping of T cell epitopes. However, comprehensive mapping of naturally recognized LMP-2 epitopes in non tumor-bearing individuals has not been reported. Here, we applied a low sensitivity epitope-defining technique for the identification of LMP-2 CTL responses detectable ex vivo in EBV-experienced individuals. This screening tool has been previously validated by analyzing memory CTL responses to Flu, cytomegalovirus (CMV), and the melanoma associated antigen gp100/Mel17. Peripheral blood monocytes (PBMC) from ten Caucasian and ten Chinese individuals were stimulated ex vivo with pools of nonamer (9-mer) peptides overlapping in a stepwise fashion each single amino acid of the LMP-2 sequence. No obvious differences were observed between the immune response of the two ethnic groups save for those related to the divergence in the ethnic prevalence of HLA haplotypes. Several novel and known LMP-2 epitopes were identified. Reactivity toward at least one LMP-2 epitope was detected in 18 of the 20 donors but no prevalent human leukocyte antigen (HLA)/epitope combination was observed confirming that LMP-2 reactivity in the context of common HLA alleles is more pleiotropic than that of FLU and CMV. We believe that the usefulness of these epitopes occurring naturally in non-cancer bearing patients as reagents for the immunization of patients with early or advanced stage NPC deserves further evaluation.
潜伏膜蛋白（LMP）-2是鼻咽癌（NPC）持续表达的一种爱泼斯坦-巴尔病毒（EBV）编码蛋白。EBV转化的淋巴母细胞系（LCL）已用于NPC患者，以诱导识别LMP-2的T细胞系，这些T细胞系又被用于T细胞表位的全蛋白图谱分析。然而，尚未有关于非荷瘤个体中天然识别的LMP-2表位的全面图谱分析报道。在此，我们应用一种低灵敏度的表位定义技术，来鉴定在有EBV接触史的个体中可在体外检测到的LMP-2细胞毒性T淋巴细胞（CTL）反应。这种筛选工具先前已通过分析对流感病毒、巨细胞病毒（CMV）以及黑色素瘤相关抗原gp100/Mel17的记忆CTL反应而得到验证。来自10名白种人和10名中国个体的外周血单核细胞（PBMC）在体外被LMP-2序列中每个单氨基酸以逐步重叠方式排列的九聚体（9-mer）肽池刺激。除了与HLA单倍型种族流行差异相关的那些反应外，未观察到两个种族群体免疫反应之间的明显差异。鉴定出了几个新的和已知的LMP-2表位。在20名供体中的18名中检测到了对至少一种LMP-2表位的反应性，但未观察到普遍的人类白细胞抗原（HLA）/表位组合，这证实了在常见HLA等位基因背景下LMP-2反应性比流感病毒和CMV的反应性更具多效性。我们认为，这些在非癌症患者中天然存在的表位作为早期或晚期NPC患者免疫治疗试剂的有用性值得进一步评估。
