TIL识别的HLA-A2限制性人黑色素瘤特异抗原肽的研究

目的：探讨TIL识别的人黑色素瘤HLA-A2限制性的肿瘤抗原肽特性。方法：通过亲和层析柱从三种肿瘤细胞系（624-Mel、Chap-Mel和JY）中纯化HLA-A2蛋白和结合的多肽分子，经弱酸高温处理和离心超滤后，应用反相．高效液相色谱层析（RT-RPLC）分离各多肽组份，并将其各组份与T2细胞共同孵育、进行重建TIL识别的人黑色素瘤特异表位试验，鉴定肽分子生物活性，通过质谱分析所获活性肽分子特性，参照活性肽序列，制备人工合成肽加以进一步证实。结果：从RT-RPLC层析的624-Mel的肽组份，经特异表位鉴定发现3个活性峰（P19、P25和P31）。其中P31，TIL杀伤率达67％，质谱分析表明肽分子量为948，氨基酸序列为H^＋Ala Lue Trp Lue Phe Phe Gly Val Lue OH^-的9肽分子。经特异表位测定表明人工合成肽具有纯化活性肽的生物活性特征。结论：分离鉴定的这-9肽分子是一种TIL识别的HLA-A2限制性肿瘤抗原肽，为肿瘤防治、合成肽疫苗的研究奠定了可靠的实验基础。     

肝素酶HLA-A2限制性CTL表位肽的筛选及其活性鉴定

目的 预测并鉴定新的人乙酰肝素酶(Hpa)抗原的HLA-A2限制性CTL表位,为恶性肿瘤多肽疫苗的免疫治疗提供依据. 方法 采用SYFPEITHI和BIMAS软件预测方法,对肝素酶HLA-A2限制性CTL表位进行预测,合成候选表位肽;利用T2细胞特点,对合成的候选肽与HLA-A2分子进行亲和力分析;利用乳酸脱氢酶释放试验检测待检肽特异性CTL诱导活性;利用ELISPOT检测T细胞活性. 结果 在所筛选的6条候选CTL表位肽中,Hpa(310～318)FLNPDVLDI与HLA-A2分子具有高亲和力,在体外可有效诱导肝素酶特异性CTL的产生,对肝素酶阳性且HLA-A2限制性的HCC-LM6肝癌细胞及SW-480结肠癌细胞具有明显的杀伤效应,且能有效诱导IFN-γ分泌,增强免疫活性. 结论 首次发现Hpa(310～318)FLNPDVLDI可能是肿瘤肝素酶抗原的HLA-A2限制性CTL表位.     

HLA-A2相关肝癌抗原肽的初步研究

目的寻找肝癌细胞表达的肿瘤抗原肽.方法应用0.2mol/Lph3.0柠檬酸缓冲液酸洗肝癌细胞系HHCC,经Sephadex G-25过滤及反向高效液相色谱分离纯化,获得可与HLA-Ⅰ类分子结合的不同组分短肽.将其与抗原加工缺陷的HLA-A2+T2细胞反应,进行肿瘤细胞特异性表位测定,同时进行CTL杀伤鉴定.结果获得4个可与HLA-A2结合的组分,其中2个可以激发较强的CTL杀伤反应.结论肝癌细胞系HHCC中存在能够激发CTL特异性反应的肿瘤抗原肽,并证实上述寻找肿瘤抗原肽的技术路线具有可行性.     

抗原NY-BR-1的HLA-A2限制性CTL表位的初步鉴定

目的：鉴定乳腺癌分化肿瘤抗原NY-BR-1的HLA-A2限制性CTL表位。方法：采用量化基序法初步预测NYBR-1的HLA-A2限制性CTL表位；分子动力学方法进一步筛选量化基序法中评分最高的3个表位肽；HLA-A2亲合力鉴定预测的结果。结果：分子动力学和HLA-A2亲合力实验均证明，在量化基序法预测的3个候选CTL表位中，NY-BR-11043-1051与HLA-A2亲合力最佳。结论：NY-BR-11043-1051可能为乳腺癌分化抗原NY-BR-1的HLA-A2限制性CTL表位。     

点突变p53肽诱导肽特异性CTL的研究

目的探索点突变ｐ５３肽诱导细胞免疫应答的可能性,为其作为肽疫苗用于肿瘤免疫治疗提供实验依据。方法人工合成小鼠点突变ｐ５３肽Ｐ１３２Ｆ（ＬＮＫＬＦＦＱＬ,１３２Ｃｙｓ→Ｐｈｅ突变）,与不完全弗氏佐剂（ＩＦＡ）或ＲＩＢＩ佐剂（ＲＡＳ）混合,皮下免疫Ｃ５７ＢＬ／６小鼠,分离脾细胞体外用肽再刺激,诱导细胞毒Ｔ淋巴细胞（ＣＴＬ）,并以５１Ｃｒ释放法检测其杀伤活性。结果Ｐ１３２Ｆ肽加上ＩＦＡ或ＲＡＳ免疫小鼠,均能诱导肽特异性ＣＤ８＋ＣＴＬ;低剂量重组白细胞介素２（ｒＩＬ－２）能增强肽免疫效果。结论所用突变的ｐ５３蛋白具有免疫原性,提示来源于突变ｐ５３的抗原肽有可能作为肽疫苗用于临床肿瘤免疫治疗     

病毒肽/HLA-A2与单链抗体融合蛋白介导病毒特异性CTL杀伤肿瘤细胞

目的 研究人工构建的病毒肽/HLA-A2复合物与抗转铁蛋白受体(CD71)单链抗体融合蛋白(HBC-A2/scFv)介导病毒特异性CTL杀伤肿瘤细胞的作用.方法 将HBC-A2/scFv融合蛋白结合到高表达CD71的肿瘤细胞表面,利用加载HBC抗原肽的 T2细胞在体外诱导产生抗原特异性CTL,用乳酸脱氢酶释放法检测CTL对肿瘤细胞的特异性杀伤作用.结果 HBC-A2/scFv融合蛋白可结合于CD71阳性的肿瘤细胞K562、HepG2及U937表面,结合率分别为:37.30%±8.25%、27.20%±3.88%和21.80%±6.49%.体外诱导产生的CTL/HBC能杀伤结合有HBC-A2/scFv的K562、HepG2及U937细胞,杀伤率明显高于未结合HBC-A2/scFv的对照组(K562:42.08%±1.14%vs 8.07%±1.39%;HepG2:49.72%±1.59%vs12.46%±1.26%;U937:39.72%±3.26%vs 7.13%±1.48%).结论 HBC-A2/scFv融合蛋白能介导病毒特异性CTL杀伤肿瘤细胞,为肿瘤细胞免疫治疗提供了新的思路和实验依据.

Abstract：

Objective To study whether the HBC-A2/scFv fusion protein mediates killing of tumor cells by viral specific cytotoxic T cells. Methods The fusion protein was attached to the CD71-expressing, HLA class Ⅰ negative tumor cells. And then, cytolysis by viral peptide-specific CTLs which were generated by co-culture of peripheral blood lymphocytes from HLA-A2 positive donors with inactivated T2 cells pulsed with the viral peptide were tested by lactate dehydrogenase (LDH) releasing. Results The fusion protein can attach the active viral peptide/HLA-A2 complex to K562, HepG2 and U937 cells through binding of CD71 scFv to CD71 (37.30% ±8.25%, 27.20% ±3.88%, 21.80% ±6.49% ) and mediate cytotoxicity of viral peptide-specific CTLs against those cells in vitro ( K562: 42.08% ± 1.14% vs 8.07%± 1.39%; HepG2: 49.72% ± 1.59% vs 12.46% ± 1.26%; U937: 39.72% ± 3.26% vs 7.13% ±1.48% ). Conclusion This viral peptide/HLA-A2 complex targeted by CD71 scFv is able to redirect viral peptide-specific T-cell mediated immune responses against tumor cells.     

Survivin-△Ex3蛋白HLA-A2．1限制性CTL表位的基因疫苗抗肿瘤效果初探

预测并合成survivin-△Ex3 HLA-A2．1限制性CTL表位的基因疫苗,探讨携带表位基因的减毒鼠伤寒沙门氏菌口服疫苗对小鼠移植肝癌模型的保护作用。将表位基因序列连接,构建pVAX1-STEs-EGFP真核表达载体,转化入减毒鼠伤寒沙门氏菌作为口服疫苗。实验动物分为未免疫对照组、口服沙门氏菌组、pVAX1质粒转染的减毒鼠伤寒沙门氏菌组;口服pVAX1-Survivin-△3（T34A）！ EGFP质粒转染的的减毒鼠伤寒沙门氏菌组和口服pVAX1-STEs ！ EGFP质粒转染的的减毒鼠伤寒沙门氏菌组。结果表明：在5组肿瘤模型小鼠中,肿瘤瘤块平均直径分别为：15．11±2．43 mm、13．70±2．97 mm、13．05±1．77 mm、7．46±2．61 mm、9．05±2．18 mm;表位疫苗组与其他组相比,有显著性差异（P＜0．01）。说明小鼠口服携带survivin-△Ex3 HLA-A2．1限制性CTL表位的基因疫苗后,能抑制小鼠肝癌细胞的增殖和扩散。     

HLA-A2+供者外周血hCMV特异性CTL的定量及其表型分析

目的:利用加载人巨细胞病毒(hCMV)结构蛋白pp65衍生抗原肽NLV(pp65495-503)的HLA-A0201(A2-NLV)四聚体,探讨四聚体染色条件的优化及其在特异性CTL表型分析中的应用。方法:取HLA-A2 供者外周血,以A2-NLV四聚体/PE在不同条件下染色,然后以anti-CD3-FITC和anti-CD8-APC标记,流式细胞术分析染色结果,寻找四聚体最佳染色条件,并分析特异性CTL的表型和活化抗原表达。结果:以全血样进行四聚体染色结果优于分离的PBMC。A2-NLV四聚体用量为0.3μg时,与100μL全血于4℃温育1h,特异性染色效果最佳,而与CD8-T细胞非特异性结合很低。以此优化条件进行特异性CTL表型分析,结果显示CD28阳性的A2-NLV四聚体特异性CTL的百分率较非特异性CTL低,表达CD57的百分率较非特异性CTL高,CD25分子只表达于活化的特异性CTL上。结论:通过对染色条件进行优化可明显提高四聚体染色的特异性,降低非特异性结合,优化的四聚体染色法能用于抗原特异性CTL的表型和功能分析。     

Hela细胞Survivin克隆及HLA-A2限制性CTL表位预测研究

目的：从Hela细胞中克隆凋亡抑制因子Survivin的编码序列,进行测序,并由此预测其HLA-A＊0201限制性CTL表位。方法：设计人Survivin基因序列特异引物,通过RT-PCR扩增Survivin编码序列,构建至pGEM-T载体后,测序分析,并对其进行了HLA-A＊0201限制性CTL表位抗原表位相关预测。结果：从Hela细胞中克隆得到的Survivin和Survivin-ΔEx3两种剪接体,其中Survivin-ΔEx3发生1个同义突变和三个错义突变,预测其抗原表位抗原性发生了变化。结论：寻找抗原性强、结合力高的表位,对于今后抗肿瘤多肽疫苗的研究具有重要的意义。     

hTERT多表位肽致敏mDC诱导CTL对HLA-A24+肿瘤细胞的特异性杀伤作用

目的:研究人工合成人端粒酶逆转录酶(hTERT)多表位混合肽经髓样树突状细胞(mDC)提呈后,诱导特异性细胞毒性T淋巴细胞(CTL)对HLA-A24+肿瘤细胞的免疫杀伤效应.方法:人工合成四分支的树状串联hTERT表位肽(MAPs)及其各单表位多肽.取HLA-A24+健康志愿者的外周血,用免疫磁珠分选并培养mDC.用尼龙毛柱纯化T淋巴细胞并培养.以各表位肽致敏mDC后,诱导特异性CTL增殖,并以表达hTERT且以HLA-A24+肿瘤细胞株SMMC-7721及HLA-A24-肿瘤细胞株SKOV3为靶细胞行杀伤实验.用ELISA法检测不同时间点培养基上清液中IL-12、TNF-α的分泌量;用流式细胞术检测CTL对肿瘤细胞的杀伤效应.结果:以源于hTERT的T淋巴细胞表位I540(ILAKFLHWL)、V461(VYGFVRACL)及L766(LTDLQPYMRQFVAHL)合成4分支MAPs多肽及各单表位混合多肽.以人工合成的hTERT 多表位混合肽致敏mDC后,能刺激CTL增殖,并可诱导对HLA-A24+肿瘤细胞株SMMC-7721的特异性杀伤作用,且MAPs多肽较单表位混合多肽的致敏效果更具显著性(P＜0.05).结论:以人工合成的hTERT多表位混合肽致敏mDC 能激活同源淋巴细胞(CTL),可特异性杀伤HLA-A2A+的肿瘤细胞,在肿瘤免疫治疗中具有重要的意义.     

丙型肝炎病毒CTL表位的HLA-A2限制性及其免疫学效应研究

目的 研究前期鉴定的5条丙型肝炎病毒(HCV)特异性细胞毒性T细胞(CTL)表位的HLA-A2限制性及其免疫学效应.方法 基于T2胞株,采用MHC-肽复合物稳定性试验研究前期鉴定的HCV特异性CTL表位与HLA-A2分子的亲和力;采用细胞内细胞因子染色(intracellular cy-tokine staining,ICS)和ELISPOT研究七述HLA-A2限制性CTL表位体外刺激HLA-A2刚性外周血单个核细胞(PBMC)产生肽特异性CTL的效应;采用CTL杀伤试验研究上述肽特异性CTL杀伤靶细胞(负载相同肽的T2细胞)的效应.结果 前期研究鉴定的5条CTL表位肽中,NS4b_78(SMMAF-SAAL)和NS5a_367(TVSSALAEL)与HLA-A2分子有高亲和力(FI1);ELISPOT结果显示NS4b_78(SMMAFSAAL)和NS5a_367(TVSSALAEL)可诱导高水平的分泌IFN-γ的效应细胞[分别为(60±6)SFC/10~4PBMC vs(4±1)SFC/10~4PBMC,P<0.001;(10±3)SFC/10~4PBMC vs(2±1)SFC/10~4PBMC,P<0.001];ICS结果证实这两条肽刺激HLA-A2阳性PBMC后,在CD8~+T细胞中产生了高百分比的CD8~+IFN-γ~+T[分别为(2.33±0.22)%vs(0.05±0.01)%,P<0.001;(0.36±0.06)%vs(0.03±0.01)%,P<0.001];并且,肽特异性CTL可特异性杀伤负载相同肽的T2细胞.结论 NS4b_78(SMMAFSAAL)和NS5a_367(TVSSALAEL)受HIA-A2限制,并具有较好的免疫原性.     

丙型肝炎病毒CTL表位的HLA-A2限制性及其免疫学效应研究

Objective To explore the HLA-A2 restriction and immunogenicity of 5 previously identified HCV-speeific CTL epitopes. Methods Based on T2 cell, to explore the HLA-A2 restriction of previously identified HCV-specific CTL epitopes by MHC-peptide complex stabilization assay;To detect pep-tide-specific CTL in HLA-A2+ PBMC stimulated by HLA-A2-restricted peptides by intracellular cytokine staining(ICS) and ELISPOT; To explore the cytotoxicity of peptide-specific CTL to same peptide-loaded T2 cells (target cells) by CTL cytotoxicity test. Results Among 5 previously identified CTL epitopes NS4b_78 (SMMAFSAAL) and NS5a_367 (TVSSALAEL) have high-affinity for HLA-A2 molecules(FI 1) ;ELISPOT results shown that NS4b_78(SMMAFSAAL) and NSSa_367(TVSSALAEL) induced high levels of IFN-γ-se-creting cells [(60±6) SFC/104 PBMC vs (4±1 ) SFC/104 PBMC, P < 0.01 ; (10 ± 3 ) SFC/104 PBMC vs (2±1 ) SFC/104 PBMC, P <0.01, respectively] ;ICS results indicated that there were high percentages of CD8 + IFN-γ+ T cells in total CD8+T cells stimulated by these peptides [(2.33 ±0.22 ) % vs (0.05±0.01)%, P <0.001 ; (0.36±0.06)% vs (0.03±0.01)%, P <0.001, respectively]. Furthermore,peptide-specific CTL could effectively kill same peptide-loadcd T2 cells. Conclusion NS4b_78 (SMMAF-SAAL) and NSSa_367 (TVSSALAEL) were identified as HLA-A2-restricted CTL epitopes which could in-duce immune response in vitro.     

Detecting specific cytotoxic T lymphocytes against SARS-coronavirus with DimerX HLA-A2:Ig fusion protein

To assess specific cytotoxic T lymphocytes (CTLs) against Severe acute respiratory syndrome (SARS)-coronavirus, a modified DimerX flow cytometry assay was performed with peripheral blood mononuclear cell (PBMC) from HLA-A2+ SARS-recovered donors at different time points post disease. CD8+DimerX-S1203+ CTLs were detected in the PBMC from these donors up to 3 months after recovery. The percentages of CD8+DimerX-S1203+ cells paralleled the numbers of interferon-gamma-positive spots in an ELISPOT assay using the same antigenic peptide. In conclusion, DimerX-based flow cytometry staining may prove to be a real-time method to screen for CTL directed at epitopes from a newly identified virus.     

胰腺癌高表达抗原MUC4 CTL表位肽的体内免疫原性

目的:检测来源于黏蛋白4(MUC4)的人白细胞抗原(HLA)-A2限制性表位肽免疫BALB/c小鼠后产生细胞免疫应答的水平,筛选出体内具有免疫原性的HLA-A2限制性表位肽。方法:将来源于MUC4的候选HLA-A2限制性表位肽、通用性Th表位和弗氏不完全佐剂联合应用皮下免疫BALB/c小鼠,用酶联免疫斑点实验(ELISPOT)和酶联免疫吸附实验(ELISA)检测小鼠脾细胞表位肽特异性细胞免疫应答的水平,体内细胞毒实验活性检测候选肽诱导细胞毒性T淋巴细胞(cytotoxic lymphocyte,CTL)的能力,并用流式细胞术检测表位肽特异性的CD8+T细胞所占比例。结果:在检测的4个表位肽中,P2004-1Y9V诱导BALB/c小鼠产生的细胞免疫应答最强,细胞毒实验结果显示,P2004和P2004-1Y9V对CAPAN-2细胞均有一定的杀伤作用,且P2004-1Y9V特异性CTLs对CAPAN-2细胞杀伤率高于原肽(P0.05)。胞内因子染色实验进一步表明P2004-1Y9V免疫后可产生特异性的CD8~+T细胞。结论:在来源于MUC4的HLA-A2限制性表位肽中,P2004-1Y9V具有较强的体内免疫原性,可以作为潜在的肿瘤多肽疫苗应用于临床研究。     

鉴别HCV C蛋白上HLA—A2限制的CTL识别表位的研究

本文先用计算机预测，后用＾５１Ｃｒ４ｈ释放分析证实的方法，对丙型肝炎病毒（ＨＣＶ）核心区蛋白（Ｃ蛋白）上，ＨＬＡ－Ａ２限制性ＣＴＬ识别表位进行了鉴别。结果发现，２名感染ＨＣＶ和ＨＬＡ－Ａ２阳性供血员的外周血单个核细胞（ＰＢＭＣ）对ＡＬＡＨＧＶＲＡＬ（ｃｏｒｅ１５０－１５８）肽段标记的自体靶细胞有溶解作用，杀伤率分别为３７．５％和１５．８％，用抗ＣＤ４ｍＡｂ阻断后杀伤率无明显变化，而用抗ＣＤ８ｍＡｂ     

慢性白血病抗原CML28 HLA-A*0201限制性CTL表位预测

目的鉴定慢性白血病肿瘤抗原CML28的HIA-A*0201限制性CTL表位。方法 采用超基序和量化基序结合的方法初步预测CM128的HLA-A*0201限制性CTL表位；利用T2细胞亲合力实验初步验证预测结果。结果 在预测的4个候选CTL表位中，ALVDAGVPM和ALDSDGTLV有较高的亲和力，ALFCGVACA和SLLACCLNA仅有低度亲和力。结论ALVDAGVPM与ALDSDGTLV最有可能是慢性白血病肿瘤抗原CML28的HLA-A*0201限制性CTL表位。     

Identification of peptide sequences that potentially trigger HLA-A2.1-restricted cytotoxic T lymphocytes

We used the human processing defective cell line 174CEM.T2 (T2) to identify potential cytotoxic T lymphocyte (CTL) epitopes of human proteins. Exogenously added peptides can increase the number of properly folded HLA-A2.1 molecules on the cell surface of T2 cells, as shown by immunofluorescence measurements using the mouse monoclonal antibody BB7.2 (anti-HLA-A2.1) and fluorescein isothiocyanate-labeled goat anti-mouse F(ab')2 antibody. The peptides were selected on the basis of a computer score derived from the recently described HLA-A2.1 specific motif. Analysis of the influenza matrix protein showed that 15 out of 35 high-scoring peptides up-regulate the expression of HLA-A2.1 molecules on theT2 cell surface. The combination of the computer scoring program and an immunofluorescence-based peptide binding assay allows rapid detection of potential CTL target peptides.     

Melanocyte lysis by cytotoxic T lymphocytes recognizing the MART-1 melanoma antigen in HLA-A2 patients with Vogt Koyanagi Harada disease

The MART-1/Melan-A melanoma antigen recognized by the majorityof HLA-A2-restricted tumorinfiltrating lymphocytes is a selfantigen expressed on melanocytes and the retina. We have investigatedwhether Vogt–Koyanagi–Harada (VKH) disease and sympatheticophthalmia (SO), systemic inflammatory disorders affecting variousorgans containing melanocytes, are autoimmune diseases directedtoward the MART-1 antigen. In two of three patients with VKHdisease and one patient with SO, CD8⁺ T cell clones (TCC) fromintraocular fluid of HLA-A2⁺ patients lysed T2 cells when pulsedwith a HLA-A2-binding MART-1 peptide, but not a HLA-A2-bindingpMel-17 or tyrosinase peptide, in a HLA-A2-restricted manner.These CD8⁺ TCC lysed both melanocytes and melanoma cells ina HLA-A2-restricted manner. In addition, CD8⁺ TCC recognizinga HLA-A2-binding MART-1 peptide were also established from peripheralblood mononuclear cells of a patient with VKH disease. In contrast,either CD4⁺ TCC from these patients or CD8⁺ TCC from the intraocularfluid of HLA-A2⁺ patients with uveitis associated with Behcet'sdisease or HTLV-I uveitis did not show this cytotoxicity. Theresults demonstrate that the MART-1 peptide-specific cytotoxicT lymphocytes lyse melanocytes in the eye of patients with VKHdisease or SO, suggesting that these diseases are autoimmunediseases directed toward the MART-1 antigen in HLA-A2⁺ patients.