应用肺癌细胞系诱生肿瘤特异性T细胞的初步研究

目的 探讨通过构建表达人白细胞抗原(HLA)HLA-A2的肺癌细胞系以诱生肿瘤特异性细胞毒性T淋巴细胞(CTL).方法 将编码HLA-A2基因的质粒pcDNA3.1D/V5转染人肺腺癌A549细胞,得到能够稳定表达HLA-A2的肺腺癌细胞系.将其用丝裂霉素(MMC)处理后,行混合淋巴细胞肿瘤细胞培养(mixed lymphocyte tumor cell culture,MLTC)以诱导HLA-A2 的健康人外周血淋巴细胞(peripheral blood lymphocyte, PBL)产生肿瘤特异性CTL,并通过特异性杀伤实验、单克隆抗体阻断实验、淋巴细胞增殖实验进行检验.结果 HLA-A·0201基因在A549细胞中的瞬时与稳定表达率分别为0.32、0.91.成功获得稳定表达HLA-A2的A549细胞株.MLTC诱导最终产生4组T淋巴细胞,且符合肿瘤特异性CTL的形态学特征与大量增殖的特点,但CTL杀伤实验和单克隆抗体阻断实验结果示肿瘤细胞未被有效杀伤,可能与肿瘤特异性CTL的数量较少及活性较低有关.结论 本研究通过构建表达HLA-A2的肺癌细胞系,对建立肿瘤特异性CTL模型作了初步探讨,为进一步完善肺癌特异性CTL细胞模型并为研究肿瘤免疫逃避、免疫耐受及反杀伤淋巴细胞等生物学行为打下基础.     

HLA-A2限制性Survivin点突变肽诱导特异性抗肝癌CTL反应

目的 探讨HLA-A2限制性Survivin点突变抗原肽体外诱导CTLs的抗肝癌作用.方法 生物信息学软件BIMAS和SYFPEITHI用来鉴定点突变的HLA-A2限制性Survivin抗原九肽;流式细胞术检测突变肽与HLA-A2分子结合效率;肽体外刺激肝癌患者腹水来源的肿瘤浸润淋巴细胞(TILs)诱导反应性CTLs,用流式细胞术及ELISA检测反应性CTLs释放IFN-γ情况;肽诱导的CTLs与肝癌细胞系HepG2及BEL-7402共孵育,CytoTox 96(R)非放射性细胞毒性检测法检测对肿瘤细胞的裂解情况,倒置相差显微镜观察肝癌细胞形态学变化.结果 生物信息学分析筛选出与MHC分子结合效率评分显著提高的点突变Survivin抗原九肽Sur79M2 (KMSSGCAFL),流式细胞术检测证实负载Sur79M2的T2细胞,HLA-A2表达率显著提高,经Sur79M2体外刺激诱导的CTLs与靶细胞共孵育后能释放较高水平的IFN-γ,Sur79M2诱导的CTLs能通过HLA-A2限制性机制有效杀伤肝癌细胞系HepG2,对HLA-A2阴性的BEL-7402细胞无明显杀伤作用.结论 点突变肽Sur79M2能在体外诱导反应性CTLs产生,该CTLs能以HLA-A2限制性方式有效杀伤肝癌细胞系.     

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.     

Effects of RNA silenced HLA-A2 in hBMSCs on secretory function of human allogeneic T lymphocytes and osteogenic ability of hBMSCs

目的:探讨应用RNAi技术沉默HLA-A2表达的人骨髓间充质干细胞(hBMSCs)对人异体T淋巴细胞分泌功能的调节作用及诱导成骨能力的影响.方法:用siRNA转染至第3代hBMSCs将转染前、后各组的hBMSCs与PHA刺激的人异体T淋巴细胞共同培养,用ELISA检测各培养组上清液γ干扰素(IFN-γ)、白细胞介素2(IL-2)的水平;对2组细胞进行成骨诱导分化培养,观察细胞形态变化;碱性磷酸酶染色、计数和Vor- Kossa染色、计数检测成骨能力.结果:hBMSCs表面抗原CD44、CD166阳性.转染前hBMSCs的HLA-A2表达为阳性,转染后hBMSCs的HLA-A2表达为弱阳性;转染前hBMSCs的HLA-A2蛋白表达量高于转染后的HLA-A2蛋白表达量.转染前、后的hBMBCs均能抑制人T淋巴细胞分泌IFN-γ、IL-2,转染前、后比较有差异.ALP染色显示转染前、后的hBMSCs均出现胞质呈棕黑色的阳性反应,ALP活性检测结果显示2组之间无差异.Vor-Kossa染色显示转染前、后的hBMSCs均有钙结节形成,统计2组之间无差异.结论:应用RNAi技术沉默HLA-A2表达的hBMSCs可以抑制PHA刺激人T淋巴细胞分泌因子IFN-γ、IL-2的水平,转染后的hBMSCs比未转染的hBMSCs抑制作用更强.应用RNAi技术沉默HLA-A2表达的hBMSCs,不影响其成骨能力.     

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.     

TLR4活化对肝癌细胞H7402生物学特征的影响

目的:分析TLR4在肝癌细胞H7402的表达水平,研究其活化对肿瘤细胞生物学功能、炎症应答以及对化疗药物治疗的影响。方法:RT-PCR方法检测肝癌细胞TLR4基因、细胞凋亡和细胞周期相关基因的表达水平。LPS作用于肝癌细胞后,利用MTT法检测细胞增殖,AnnexinV/PI双染法检测细胞凋亡,荧光定量PCR法检测肿瘤相关细胞因子的表达水平,流式细胞术检测肿瘤细胞表面淋巴细胞受体的配体及CyclinD1表达,Western blot检测Bcl-xl表达水平。结果:TLR4在人肝癌细胞系HepG2、H7402、PLC/PRF/5中都有表达,LPS能促进肝癌细胞系的增殖,抵抗顺铂的抗肿瘤作用。进一步的机制研究表明,LPS能上调肝癌细胞周期相关分子CyclinD1、凋亡相关分子Bcl-xl的表达,并下调Fas的表达、上调肿瘤相关的炎症因子的表达。结论:LPS诱导肝癌细胞H7402表达炎症因子、促进肿瘤细胞的增殖,导致肿瘤细胞对化疗药顺铂产生抵抗作用。     

siRNA沉默HLA-A2表达的hMSCs对人异体T淋巴细胞分泌IFN-γ和IL-2功能的影响

目的探讨应用siRNA技术下调HLA-A2表达的人骨髓间充质干细胞(human mesenchymal stemcells,hMSCs)对人异体T淋巴细胞分泌功能的调节作用。方法从成人骨髓中分离和培养hMSCs,并且通过免疫细胞化学检测其表面标志;利用人工合成HLA-A2靶向小分子干扰RNA转染至第3代hMSCs,然后将转染前后的hMSCs,与经植物血凝素(PHA)刺激的人异体T淋巴细胞共同培养。用ELISA分别检测各培养上清液中T淋巴细胞分泌IFN-γ和IL-2的水平。结果原代培养3d后,约70%hMSCs贴壁生长,7d后细胞迅速增殖,进入对数生长期,14d左右进入平台期,第3代细胞多呈梭形生长,形态比较均一,hMSCs表面抗原CD44、CD166阳性。HLA-A2靶向小分子干扰RNA转染3天后,可见少量细胞死亡,免疫荧光染色可见细胞核和部分胞浆呈阳性表达。转染HLA-A2靶向小分子干扰RNA的和未转染的hMSCs均能抑制人T淋巴细胞分泌IFN-γ和IL-2,转染后的hMSCs抑制作用强于未转染的hMSCs(<0.05)。结论体外沉默HLA-A2基因表达可增强hMSCs抑制PHA刺激人T淋巴细胞分泌因子。     

小儿急性淋巴细胞白血病与HLA基因多态性相关性的研究

目的:对小儿急性淋巴细胞白血病患者进行HLA基因多态性分型,寻找急性淋巴细胞白血病的易感基因.方法:采用特异性寡核苷酸探针杂交(PCR/SSO)法,对儿童急性淋巴细胞白血病患者和健康对照组进行HLA-A、B、DRB1基因分型.结果:在儿童急性淋巴细胞白血病患者中HLA-A01、A02、HLA-DRB1*01、HLA-DRB1*15基因位点较对照组明显升高(P<0.05).A11、A33、HLA-DRB1*03基因位点频率较对照组降低(P<0.05).其中HLA-A01、HLA-DRB1*01、HLA-DRB1*15基因位点相对危险率RR>4,而A11、A33、HLA-DRB1*03基因位点相对危险率RR<1.结论:HLA-A01、A02、A33、HLA-DRB1*01、DRB1*03、DRB1*15与小儿急性淋巴细胞白血病有相关性.其中HLA-A01、HLA-DRB1*01、HLA-DRB1*15对儿童白血病有遗传易感性.A11、A33、HLA-DRB1*03则对青海地区汉族小儿急性淋巴细胞白血病的发生有拮抗作用.     

肝癌TIL细胞转导IL-2基因的生物学变化研究

目的：为探讨ＩＬ－２基因导入肝癌浸润淋巴细胞及是其生物学活性的影响。方法：应用逆转录病毒载体介导ＩＬ－２基因导入人肝癌浸润淋巴细胞（ＴＩＬ）,同时对经转导ＩＬ－２基因的肝癌浸润淋巴细胞的杀伤活性,增殖能力及表型等进行了观察。结果：转导ＩＬ－２基因后的肝癌浸润淋巴细胞能表达一定量的ＩＬ－２,明显高于未转导细胞,但其杀伤肿瘤细胞活性,增殖能力及表型等没有显著变化。结论：应用逆转录病毒载体介导ＩＬ－２基     

肿瘤抗原PIWIL2的HLA-A2限制性CTL表位鉴定

目的:鉴定肿瘤抗原PIWIL2的人类白细胞抗原A2(HLA-A2)限制性细胞毒性T淋巴细胞(CTL)表位。方法:首先运用RT-PCR、Western blot方法检测PIWIL2在肿瘤细胞系MCF-7、SW480和HT-29中的表达情况,然后通过BIMAS、Rank Pep、Net MHC、Net CTL1.2及IEDB软件预测打分来选取PIWIL2的HLA-A2限制性的表位。候选表位肽通过标准的Fmoc化学合成法合成,结合力实验用于检测候选表位与T2A2细胞表面HLA-A2分子的结合能力,ELISPOT实验检测候选表位肽诱导CTL分泌IFN-γ的能力,体外细胞毒性实验检测候选肽诱导CTL的能力。结果:PIWIL2在肿瘤细胞系MCF-7、SW480和HT-29中均有表达。候选肽P485、P493、P965具有中等结合力。ELISPOT实验结果显示表位肽P485和P965诱导的CTL具有分泌IFN-γ的能力。细胞毒性实验结果显示表位肽P485和P965对MCF-7细胞均有一定的杀伤作用。结论:表位肽P485和P965是优秀的PIWIL2抗原HLAA2限制性CTL候选表位,可能成为新的抗肿瘤多肽免疫治疗疫苗的候选表位。     

Identification of a new HLA-A*0201-restricted CD8+ T cell epitope from hepatocellular carcinoma-associated antigen HCA587

For the development of peptide-based cancer immunotherapies, we aimed to identify specific HLA-A*0201-restricted CTL epitopes in hepatocellular carcinoma (HCC) associated antigen HCA587, which has been identified as a member of the cancer/testis (CT) antigens highly expressed in HCC. We first combined the use of an HLA-A*0201/peptide binding algorithm and T2 binding assays with the induction of specific CD8(+) T cell lines from normal donors by in vitro priming with high-affinity peptides, then IFN-gamma release and cytotoxicity assays were employed to identify the specific HLA-A*0201 CD8(+) T cell epitope using peptide-loaded T2 cells or the HCA587 protein(+) HCC cell line HepG2. In the six candidate synthesized peptides, two peptides showed higher binding ability in T2 binding assays. No. 2 peptide, encompassing amino acid residues FLAKLNNTV (HCA587(317-325)), was able to activate a HCA587-specific CD8(+) T-cell response in human lymphocyte cultures from two normal donors and two HCC patients, and these HCA587-specific CD8(+) T cells recognized peptide-pulsed T2 cells as well as the HCA587 protein(+) HCC cell line HepG2 in IFN-gamma release and cytotoxicity assays. The results indicate that no. 2 peptide is a new HLA-A*0201-restricted CTL epitope capable of inducing HCA587-specific CTLs. Our data suggest that identification of this new HCA587/HLA-A*0201 peptide FLAKLNNTV may facilitate the design of peptide-based immunotherapies for the treatment of HCA587-bearing HCC patients.     

The expression of MHC antigens by human teratocarcinoma derived cell lines

We have used flow microflourimetry to investigate quantitatively the expression of HLA-A, B and C antigens, and β₂ microglobulin, by cell lines derived from human teratocarcinomas. Although low levels of these cell surface molecules were expressed by all the lines examined, there was no evidence of discrete HLA-A, B, C/β₂-microglobulin positive and negative subpopulations in any cultures. In contrast, using similar techniques, no murine embryonal carcinoma cell line was found to express the homologous H-2 antigens. It is suggested that human embryonal carcinoma cells may differ from their mouse counterparts by expressing low levels of major histocompatibility antigens.     

Recognition of shared melanoma antigen by HLA-A2-restricted cytolytic T cell clones derived from human tumor-infiltrating lymphocytes

Three melanoma-specific cytotoxic T lymphocytes (CTL) clones were derived from the tumor-infiltrating lymphocyte (TIL) of human melanoma M17, and were used to study the expression of immunogenic melanoma peptides on allogeneic tumors. Antibody inhibition studies showed that two of these TIL clones were restricted by an HLA-A2 molecule which was identified as A2.1 by gene sequencing. The third CTL clone was not restricted by HLA-A2, but by a B or C HLA antigen. HLA-A2-restricted CTL clones M17-1 and M17-2 lysed 5 and 12 out of 15 HLA-A2⁺ allogeneic melanomas, respectively. Since they did not lyse autologous Epstein-Barr virus B cells, HLA-A2.1-transfected P815 cells,13 HLA-A2⁺ non-melanoma tumor cell lines and 10 HLA-A2^? melanomas, these clones appeared specific for melanoma-restricted epitopes presented by the HLA-A2.1 molecule. We then tried to determine why a few HLA-A2⁺ melanomas were refractory to TIL lysis. By using a combination of flow cytometry analysis, partial cloning and sequencing of their HLA-A2 genes, we show that failure to lyse did not result from low expression or polymoprhism of the HLA-A2 molecule, or from deficient expression of the adhesion molecules ICAM-1 and LFA-3 by these melanomas. Taken together, our data confirm at the clonal level the existence of shared melanoma antigens recognized by TIL in the HLA-A2.1 context. They further show that individual peptides derived from these antigens are expressed by a large majority of HLA-A2⁺ melanomas. Identification of such peptides appears crucial for the future of vaccination therapies.     

Expression of HLA class I antigens in transporter associated with antigen processing (TAP)-deficient mutant cell lines

Abstract: Cells lacking expression of the transporter associated with antigen processing (TAP) are deficient in surface HLA class I, yet express reduced levels of HLA-A2 antigen through TAP-independent processing pathways. We have analysed the expression of HLA-A, -B and -C antigens on the 721.174 and T2 TAP-deficient mutant cell lines using a panel of monoclonal antibodies specific for the HLA antigens encoded by the genotype of these cells. Our study has shown the constitutive expression of HLA-Cwl molecules on the cell surface of both T2 and 721.174 cells and has confirmed that HLA-A2 and HLA-B51 are expressed at low levels. Transfection of 721.174 cells with cDNAs encoding TAP1 and TAP2 proteins did not fully restore HLA class I antigen expression on these cells, which appeared to be mainly due to a deficiency in expression of the HLA-B51-associ-ated Bw4 epitope. This suggests that additional antigen-processing genes may be required for optimal generation of HLA-B-binding peptides. Our results indicate that TAP-independent pathways of antigen-processing provide peptides for functional expression of all three classical HLA class I molecules.     

Modulation of MHC gene expression in human breast carcinoma cells by hormones

Products encoded by the class I Major Histocompatibility Complex (MHC) genes serve as restriction molecules which enable T cells to generate an immune response to specific antigens. Recently, many investigators have demonstrated the importance of class I antigens in enabling the host to regulate tumor growth in vivo. In this report, we have studied the regulation of HLA genes by hormones in human breast cancer cell lines. Eight lines were studied. Using HLA locus-specific DNA probes, the level of HLA-A and HLA-B specific mRNAs were found to be underrepresented in six of these cell lines when compared to an epithelial cell line derived from a normal lactating breast. Moreover, the expression of class I MHC mRNA in these cells correlated well with the level of chloramphenicol acetyltransferase (CAT) activity detected after the introduction of exogenous HLA-CAT DNA-constructs. It was also found that HLA expression in some of the breast carcinoma cell lines could be modulated by the addition of hormones. Hence, HLA mRNA expression in the cell line MCF-7 was enhanced by the addition of estrogen; but was down-regulated in the presence of dexamethasone. Conversely, for T-47D cells, HLA expression was suppressed by progesterone. These results indicate that hormones could have an influence on the expression of HLA genes and may therefore indirectly be involved in the regulation of tumor growth by the host's immune system.     

Tissue Typing of Cells in Culture. IV. Cell Surface Antigens of Tumor Cell Lines, not Obviously Belonging to the HLA-System

Studies on the HLA pattern of several human tumor cell lines by the mixed hemadsorption test and also studies on the discriminative patterns formed by a collection of sera on a number of cell lines and diploid cells have been reported elsewhere. It was noted during these studies that some sera reacted in a fashion indicating that they did not represent any of the HLA-A or -B series and probably not the HLA-C series either. The corresponding antigenic determinants were tentatively designated Ek-1 to Ek-11. The pattern of these antigens among the cell lines is given in a table and it seems apparent that the Ek-series considerably increases the cell identification potential of the typing results. So far, five of the sera determining the Ek-antigens have failed to be blocked by anti-beta-2-microglobulin, indicating that the antigens do not belong to the HLA-A, B or C series. Preparatory work for HLA-D typing is under way.     

Identification of ribosomal proteins S2 and L10a as tumor antigens recognized by HLA-A26-restricted CTL

Recent identification of cytotoxic T lymphocyte (CTL)-directed peptides binding to the HLA-A2 and -A24 alleles has opened the door to peptide-based cancer immunotherapies. However, subsequent studies have succeeded in identifying no more than a few CTL-directed peptides that bind to alleles other than HLA-A2 and -A24, thus hampering development of immunotherapies directed at other alleles. We have shown in this study that two genes coding for ribosomal proteins (S2 and L10a) encoded tumor antigens recognized by HLA-A26-restricted CTLs. The S2 mRNA was expressed in all of the cancer cells and non-malignant cell lines tested, but was not expressed in normal tissues except for the testis, muscle, and peripheral mononuclear leukocyte cell (PBMC). In contrast, the L10a mRNA was expressed in all of these cancer and non-malignant cell lines, and also normal tissues, although the expression levels in normal tissues were mostly low. One S2-derived peptide and two L10a-derived peptides had the ability to induce HLA-A26-restricted and peptide-specific CTLs reactive to tumor cells in PBMCs of cancer patients, respectively. These ribosomal protein-derived peptides, and particularly the S2-derived peptide, could be suitable for use in peptide-based immunotherapy for HLA-A26+ cancer patients.     

Analysis of endogenous peptides bound by soluble MHC class I molecules: a novel approach for identifying tumor-specific antigens.

The Human MHC Project aims at comprehensive cataloging of peptides presented within the context of different human leukocyte antigens (HLA) expressed by cells of various tissue origins, both in health and in disease. Of major interest are peptides presented on cancer cells, which include peptides derived from tumor antigens that are of interest for immunotherapy. Here, HLA-restricted tumor-specific antigens were identified by transfecting human breast, ovarian and prostate tumor cell lines with truncated genes of HLA-A2 and HLA-B7. Soluble HLA secreted by these cell lines were purified by affinity chromatography and analyzed by nano-capillary electrospray ionization-tandem mass spectrometry. Typically, a large peptide pool was recovered and sequenced including peptides derived from MAGE-B2 and mucin and other new tumor-derived antigens that may serve as potential candidates for immunotherapy.