In-vitro activation of cytotoxic T lymphocytes by fusion of mouse hepatocellular carcinoma cells and lymphotactin gene-modified dendritic cells

AIM： To investigate the in-vitro activation of cytotoxic T lymphocytes （CTLs） by fusion of mouse hepatocellular carcinoma （HCC） ceils and lymphotactin gene-modified dendritic cells （DCs）. METHODS： Lymphotactin gene modified DCs （DCLptn） were prepared by lymphotactin recombinant adenovirus transduction of mature DCs which differentiated from mouse bone marrow cells by stimulation with granulocyte/macrophage colony-stimulating factor （GM- CSF）, interleukin-4 （IL-4） and tumor necrosis factor alpha （TNF-α）. DCLptn and H22 fusion was prepared using 50% PEG. Lymphotactin gene and protein expression levels were measured by RT-PCR and ELISA, respectively. Lymphotactin chemotactic responses were examined by in-vitro chemotaxis assay. In-vitro activation of CTl_s by DCLptn/H22 fusion was measured by detecting CD25 expression and cytokine production after autologous T cell stimulation. Cytotoxic function of activated T lymphocytes stimulated with DCLptn/H22 cells was determined by LDH cytotoxicity assay. RESULTS： Lymphotactin gene could be efficiently transduced to DCs by adenovirus vector and showed an effective biological activity. After fusion, the hybrid DCLptn/H22 cells acquired the phenotypes of both DCLptn and H22 cells. In T cell proliferation assay, flow cytometry showed a very high CD25 expression, and cytokine release assay showed a significantly higher concentration of IFN-α, and IL-2 in DCLptn/H22 group than in DCLptn, DCLptn＋H22, DC/H22 or H22 groups. Cytotoxicity assay revealed that T cells derived from DCLptn/H22 group had much higher anti-tumor activity than those derived from DCLptn, H22, DCLptn ＋ H22, DC/H22 groups. CONCLUSION： Lymphotactin gene-modified dendritoma induces T-cell proliferation and strong CTL reaction against allogenic HCC cells. Immunization-engineered fusion hybrid vaccine is an attractive strategy in prevention and treatment of HCC metastases.

Identification of the epitopes on HCV core protein recognized by HLA-A2 restricted cytotoxic T lymphocytes

AIM: To identify hepatitis C virus(HCV) core protein epitopes recognized by HLA-A2 restricted cytotoxic T lymphocyte (CTL). METHODS: Utilizing the method of computer prediction followed by a 4h(51)Cr release assay confirmation. RESULTS: The results showed that peripheral blood mononuclear cells (PBMC) obtained from two HLA-A2 positive donors who were infected with HCV could lyse autologous target cells labeled with peptide "ALAHGVRAL (core 150-158)". The rates of specific lysis of the cells from the two donors were 37.5% and 15.8%, respectively. Blocking of the CTL response with anti-CD4 mAb caused no significant decrease of the specific lysis. But blocking of CTL response with anti-CD8 mAb could abolish the lysis. CONCLUSION: The peptide (core 150-158) is the candidate epitope recognized by HLAA2 restricted CTL.

Frequencies and Characterization of HBV-specific Cytotoxic T Lymphocytes in Self-limited and Chronic Hepatitis B Viral Infection in China

Hepatitis B virus （HBV）-specific cytotoxic T lymphocytes （CTLs） are believed to play a major role in viral clearance and disease pathogenesis during HBV infection. To clarify the differences in host immune responses between self-limited and chronic HBV infections, we constructed three HLA-A＊0201/HBV tetramers with immunodominant epitopes of core18-27, polymerase 575-583 and envelope 335-343, and analyzed the HBV-specific CTLs in peripheral blood mononuclear cells （PBMCs） from patients infected with HBV. The frequencies and expansion ability of HBV-specific CD8＋T cells in most self-limited HBV infected individuals were higher than those in chronic HBV-infected patients. HBV-specific CD8＋T cells could be induced by in vitro peptide stimulation from chronic patients with a low level of serum HBV-DNA but not from those with a high level of serum HBV-DNA. In chronic infection, no significant correlation was found either between the frequencies of HBV-specific CD8^＋ T cells and the viral load, or between the frequencies and the levels of alanine transaminase. Our results suggested that the frequencies of HBV-specific CTLs are not the main determinant of immune-mediated protection in chronic HBV infection and immunotherapeutic approaches should be aimed at not only boosting a HBV-specific CD8^＋T response but also improving its function.

Glypican-3-specific cytotoxic T lymphocytes induced by human leucocyte antigen-A*0201-restricted peptide effectively kill hepatocellular carcinoma cells in vitro

Objective: To investigate potential human leucocyte antigen(HLA)-A2-restricted epitope peptides of glypican-3(GPC3) and determine the cytotoxicity of peptidespecific cytotoxic T lymphocytes(CTLs) against hepatocellular carcinoma(HCC) cells.Methods: The potential HLA-A*0201-restricted GPC3 peptides were screened using computer algorithms, T2 cell-binding affinity and stability of peptide/HLA-A*0201 complex assay. The peptide-specific CTLs were generated and their cytotoxicity against GPC3+SMMC 7721 and Hep G2 cells was detected using IFN-g based enzymelinked immunospot and lactate dehydrogenase release assays in vitro.Results: A total of six peptides were identified for bindings to HAL-A2 and the GPC3522–530 and GPC3 229–237 peptides with HLA-A*0201 molecules displayed high binding affinity and stability. The CTLs induced by the GPC3 522–530 or positive control GPC3 144–152 peptide responded to the peptide by producing IFN-g, which were abrogated by treatment with anti-HLA-A2 antibody. The GPC3 522–530-specific CTLs responded to and killed SMMC 7721 and Hep G2 cells, instead of GPC3-silenced SMMC7721 or Hep G2 cells. GPC3 522–530-specific CTLs response to HCC cells was blocked by anti-HLA-A2 antibody.Conclusions: The GPC3 522–530 peptide contains antigen-determinant and its specific CTLs can effectively kill HCC in a HLA-A2-restricted and peptide-dependent manner. Our findings suggest that this peptide may be valuable for development of therapeutic vaccine.

INVESTIGATION OF INDUCING EFFECT OF SPECIFIC CYTOTOXICITY OF CTLS BY ANTIGEN PEPTIDES FROM T LYMPHOCYTIC LEUKEMIA CELLS

Objective: To investigate the characteristics of specific antitumor immunity induced by antigen peptides mixture from T lymphocytic leukemia cells. Method: Antigen peptides mixtures were prepared from different leukemia cell lines and then bound with Hsp70 in vitro. Human peripheral blood mononuclear cells (PBMC) were cultured in vitro, and activated with Hsp70-antigen peptides. The activated PBMC was cultured continuously in vitro, and used as effector cells in vitro test of cytotoxicity to different target cells. Results: The antigen peptides from different leukemia cell lines were peptides mixture and could activate PBMC effectively if they were presented by Hsp70. The activated PBMC could proliferate in the presence of IL-2 and Hsp70-antigen peptides. The proliferative PBMC had specific cytotoxicity to leukemia cells corresponding to the antigen peptides. PBMC activated by antigen peptides from T lymphocytic leukemia cell lines could effectively kill T lymphocytic leukemia cells, and the cytotoxicity of these PBMC to T lymphocytic leukemia cells was significantly stronger than that of PBMC activated by antigen peptides from other leukemia cells (P < 0.05). PBMC activated by either Hut78-peptides or Molt 4-peptides could effectively kill Jurkat cells. And the cytotoxicity of PBMC activated by Hut78/Molt-4-peptides to Jurkat cells was significantly stronger than that of PBMC activated by either Hut78-peptides or Molt-4-peptides alone (P<0.05). Conclusion: Antigen peptides mixture from T lymphocytic leukemia cell lines can induce specific cytotoxic effect to T lymphocytic leukemia cells. There exists cross-reactivity among antigen peptides mixture from different T lymphocytic leukemia cell lines. The cross-reactivity could be amplified by blending of different antigen peptides from different T lymphocytic leukemia cell lines, suggesting that it is possible to prepare broad-spectrum antigen peptide vaccine against T lymphocytic leukemia by using multiple leukemia cell lines.

Dendritic cells engineered to secrete anti-Dc R3 antibody augment cytotoxic T lymphocyte response against pancreatic cancer in vitro

AIM To investigate the enhanced cytotoxic T lymphocyte responses against pancreatic cancer (PC) in vitro induced by dendritic cells (DCs) engineered to secrete anti-DcR3 monoclonal antibody (mAb). METHODS DCs, T lymphocytes and primary PC cells were obtained from PC patients. DCs were transfected with a designed humanized anti-DcR3 monoclonal antibody heavy and light chain mRNA and/or total tumor RNA (DC-tumor-anti-DcR3 RNA or DC-total tumor RNA) by using electroporation technology. The identification, concentration and function of anti-DcR3 mAb secreted by DC-tumor-anti-DcR3 RNA were determined by western blotting and enzyme-linked immunosorbent assay. After co-culturing of autologous isolated PC cells with target DCs, the effects of secreting anti-DcR3 mAb on RNA-DCs' viability and apoptosis were assessed by MTT assay and flow cytometry. Analysis of enhanced antigen-specific immune response against PC induced by anti-DcR3 mAb secreting DCs was performed using a Cr-51 releasing test. T cell responses induced by RNAloaded DCs were analyzed by measuring cytokine levels, including IFN-gamma, IL-10, IL4, TNF-alpha and IL-12. RESULTS The anti-DcR3 mAb secreted by DCs reacted with recombinant human DcR3 protein and generated a band with 35 kDa molecular weight. The secreting mAb was transient, peaking at 24 h and becoming undetectable after 72 h. After co-incubation with DCtumor- anti-DcR3 RNA for designated times, the DcR3 level in the supernatant of autologous PC cells was significantly down-regulated (P < 0.05). DCs secreting anti-DcR3 mAb could improve cell viability and slow down the apoptosis of RNA-loaded DCs, compared with DC-total tumor RNA (P < 0.01). The anti-DcR3 mAb secreted by DC-tumor-anti-DcR3 RNA could enhance the induction of cytotoxic T lymphocytes (CTLs) activity toward RNA-transfected DCs, primary tumor cells, and PC cell lines, compared with CTLs stimulated by DC-total tumor RNA or control group (P < 0.05). Meanwhile, the antigen-specific CTL responses were MHC class I-restricted. The CD4+ T cells and CD8+ T cells incubated with anti-DcR3 mAb secreting DCs could produce extremely higher level IFN-gamma and lower level IL4 than those incubated with DC-total tumor RNA or controls (P < 0.01). CONCLUSION DCs engineered to secrete anti-DcR3 antibody can augment CTL responses against PC in vitro, and the immune-enhancing effects may be partly due to their capability of down-regulating DC apoptosis and adjusting the Th1/Th2 cytokine network.

Association of Graves’ disease and Graves’ ophthalmopathy with the polymorphisms in promoter and exon 1 of cytotoxic T lymphocyte associated antigen-4 gene

Objective: To investigate the association of Graves’ disease and Graves’ ophthalmopathy with the C/T transition polymorphism at position –318 of promoter and the A/G transition polymorphism at position 49 of exon 1 within cytotoxic T lymphocyte associated antigen-4 (CTLA-4) gene. Methods: Thirty-three patients with ophthalmopathy of Graves’ disease, fifty-six Graves’ patients without ophthalmopathy and sixty normal subjects as control were involved in the present case-control study. The polymorphisms were evaluated by polymerase chain reaction fragment length polymorphism (PCR-RFLP). Com-parisons were made of gene frequencies and allele frequencies between the groups. Results: The gene frequencies of CT and allele frequencies of T were much higher in Graves’ patients with ophthalmopathy than that in the group without ophthalmopathy (P=0.020, P=0.019). The gene frequencies of GG and allele frequencies of G in patients with Graves’ disease were significantly increased as compared with control group (P=0.008, P=0.007). The data suggest that smokers with Graves’ disease seemed to be more predisposed to ophthalmopathy than non-smokers (P=0.018). Conclusion: Our results suggest that an allele of T at position –318 of promoter is associated with genetic susceptibility to Graves’ ophthalmopathy while an allele of G at position 49 of exon 1 is associated with genetic susceptibility to Graves’ disease instead. Smoking is believed to be a major risk factor for ophthalmo-pathy.

Effect of cytotoxic T-lymphocyte antigen-4,TNF-alpha polymorphisms on osteosarcoma: evidences from a meta-analysis

Objective： Previous studies have investigated the role of cytotoxic T-lymphocyte antigen-4 （CTLA-4） and tumor necrosis factor-alpha （TNF-a） in carcinogenesis of osteosarcoma, but their results were inconsistent. We aimed to clarify the associations between CTLA-4, TNF-a polymorphism and osteosarcoma risk by using meta-analysis. Methods： We searched relevant studies without language restriction in PubMed, EMbase, Cochrane Library, Google Scholar databases, Chinese National Knowledge Infrastructure （CNKI） and conference literature in humans published prior to March 2013. The strengths of the associations between genetic variants and osteosarcoma risk were estimated by odds ratio （OR） with 95% confidence interval （95% CI）. Results： A total of seven studies with 1,198 osteosarcoma patients and 1,493 controls were selected. Four studies were eligible for CTLA-4 （1,003 osteosarcoma and 1,162 controls）, and three studies for TNF-a （195 osteosarcoma and 331 controls）. Pooled results showed that rs231775 polymorphism of CTLA-4 was associated with osteosarcoma risk （GG vs. AA： OR=1.63, 95% CI=1.24-2.13; GG ＋ GA vs. AA： OR=1.56, 95% CI=1.21-2.01; AA ＋ GA vs. GG： OR=0.83, 95% CI=0.71-0.97; G vs. A： OR=1.21, 95% CI=1.08-1.36）. No significant heterogeneity was observed across the studies. No significant associations were found between rs5742909 polymorphism of CTLA-4 or rs1800629 polymorphism of TNF-a and osteosarcoma risk. Conclusions： These results suggest that the rs231775 polymorphism of CTLA-4 may play an important role in carcinogenesis of osteosarcoma.

GPC3刺激对DC-CTL靶向杀伤肝细胞癌的影响

目的本研究将磷脂酰肌醇蛋白聚糖3(GPC3)作为肝细胞癌(LIHC)的靶分子,研究其在激活树突状细胞(DC)-细胞毒性T淋巴细胞(CTL)和增强肿瘤杀伤能力中的作用。方法为更系统、更全面地鉴定GPC3在多种恶性肿瘤中的意义,对GPC3在泛癌中的基因表达水平进行评估,并从LIHC与临床特征的相关性角度进一步研究GPC3。分别通过生存预后分析(Kaplan-Meier图)和受试者工作特征(ROC)曲线分析评估GPC3在LIHC中的预后价值和诊断价值。重组GPC3蛋白用于刺激DC,然后与CTL细胞共培养,经酶联免疫吸附试验(ELISA)分析以检测DC-CTL细胞中细胞因子的表达。通过CCK8测定法测定在Huh7细胞上用GPC3培养刺激的DC-CTL细胞的细胞毒性。结果GPC3的基因表达水平在大多数癌症中显著不同,并且在LIHC中与正常组织相比更高。GPC3在血清中与年龄和甲胎蛋白(AFP)水平相关(均P<0.001),而与LIHC的TNM分期、病理分期和组织学分级无关。ROC曲线分析表明,GPC3可用于准确预测LIHC。GPC3的表达水平与LIHC的总生存期无关。联合治疗显著上调了IFN-γ和TNF-α的分泌。用150 ng/ml和200 ng/ml GPC3刺激的DC-CTL细胞杀死Huh7细胞的能力强于不使用GPC3刺激的DC-CTL细胞(均P<0.05)。结论用GPC3刺激DC-CTL细胞通过促进细胞毒性在体外抑制肿瘤生长。GPC3可能是一种潜在的肿瘤标志物,可用于提高DC-CTL细胞的治疗效率。

初诊SLE患者抗CTLA-4抗体水平及其临床意义

目的探讨初诊系统性红斑狼疮(SLE)患者血清中抗CTLA-4抗体水平及其临床意义。方法选取2022年1月至2023年6月在苏州大学附属第一医院风湿免疫科就诊的初诊SLE患者56例作为病例组,同时选取我院体检中心52例体检者作为对照组。采用酶联免疫吸附试验(ELISA)检测两组血清中IgG和IgM型抗CTLA-4抗体。比较不同临床特征(包括皮疹、口腔溃疡、浆膜炎等等)初诊SLE患者组间抗CTLA-4抗体水平差异。采用Pearson相关分析评估初诊SLE患者抗CTLA-4抗体与疾病活动指标[包括SLE疾病活动指数2000版(SLEDAI-2K)、抗ds-DNA以及C反应蛋白(CRP)]的关系。结果病例组IgG和IgM型抗CTLA-4水平均高于对照组(t=4.657、5.014,P均<0.05);IgG和IgM型抗CTLA-4抗体水平在SLE合并浆膜炎的患者中高于未合并浆膜炎患者(t=1.849、2.013;P=0.046、0.032);Pearson相关分析显示,IgM型抗CTLA-4抗体与SLEDAI-2K(r=0.425,P=0.029)及补体C3(r=-0.494,P=0.029)呈正相关;IgG和IgM型抗CTLA-4抗体与CRP(r=0.301、0.404;P=0.041、0.022)和抗ds-DNA抗体(r=0.644、0.363;P=0.002、0.036)呈正相关。结论初诊SLE患者血清抗CTLA-4抗体呈高表达,且该抗体与浆膜炎、疾病活动度相关。

隔药饼灸对环磷酰胺诱导免疫抑制兔共刺激分子CTLA-4、4-1BB、CD28的影响

目的探讨隔药饼灸对环磷酰胺诱导免疫抑制兔共刺激分子细胞毒性T淋巴细胞相关抗原4(CTLA-4)、4-1BB、CD28的影响。方法选择大耳白兔32只,随机分为空白组、模型组、艾条灸组和隔药饼灸组,每组8只。模型组、艾条灸组和隔药饼灸组予环磷酰胺诱导免疫抑制模型。模型制备成功次日,艾条灸组和隔药饼灸组分别予艾条灸和隔药饼灸,隔日1次,共10次。空白组和模型组不予艾灸。艾条灸组和隔药饼灸组末次干预次日,空白组和模型组同时间,采集腹腔静脉血,离心留取血清,采用ELISA法检测血清CTLA-4、4-1BB、CD28;腹腔静脉取血后,摘取脾脏和肝脏,免疫组化法检测脾脏和肝脏组织CTLA-4、4-1BB蛋白表达。结果模型组血清CTLA-4、CD28水平均高于空白组,血清4-1BB水平低于空白组(P均<0.05);与模型组比较,艾条灸组和隔药饼灸组血清CTLA-4、CD28水平均降低,血清4-1BB水平均升高(P均<0.05);与艾条灸组比较,隔药饼灸组血清CTLA-4、CD28水平均降低,血清4-1BB水平升高(P均<0.05)。模型组脾脏和肝脏组织CTLA-4阳性表达均高于空白组,4-1BB阳性表达均低于空白组(P均<0.05)。与模型组比较,艾条灸组脾脏和肝脏组织CTLA-4阳性表达均降低(P均<0.05),肝脏组织4-1BB阳性表达升高(P<0.05),而脾脏组织4-1BB阳性表达升高不明显(P>0.05);隔药饼灸组脾脏和肝脏组织CTLA-4阳性表达均降低(P均<0.05),4-1BB阳性表达均升高(P均<0.05)。艾条灸组与隔药饼灸组脾脏和肝脏组织CTLA-4、4-1BB阳性表达比较差异均无统计学意义(P均>0.05)。结论隔药饼灸能够通过调节共刺激分子CTLA-4、4-1BB、CD28而改善环磷酰胺诱导免疫抑制兔的免疫功能,其效果优于艾条灸。

CTLA-4与PD-1/PD-L1免疫检查点抑制剂治疗子宫内膜癌新进展

免疫检查点抑制剂(ICIs)是可调节免疫反应。细胞毒性T淋巴细胞相关抗原4 (CTLA-4)和程序性死亡受体1 (PD-1)/程序性死亡受体配体1 (PD-L1)对应的免疫检查点抑制剂已在临床抗肿瘤中展现出极大优势。免疫检查点抑制剂通过阻断免疫检查点通路,激活免疫细胞识别和杀伤的功能治疗子宫内膜癌,从而达到抗肿瘤效果,应用前景广阔。

MUC1 Antigen-Specific CD8 T Lymphocytes Targeting MCF7 and MDA-MB-231 Human Breast Adenocarcinoma Cell Lines

MUC1 is an antigen that is overexpressed on the cell surface of many human breast adenocarcinomas and other types of cancer. The cancer immunity cycle has seven steps, starting with release of cancer cell antigen and following with cancer antigen presentation. Priming, activation and trafficking of T cells to tumors are the next steps and the infiltration of T cells into tumors, the recognition of cancer cells by T cells and killing of cancer cells are the final steps. We have tested a synthetic peptide for the MUC1 antigen and generated dendritic cells (DCs) that were pulsed with the specific peptide. Mature DCs were used to activate naive T cells to differentiate into antigen-specific CTLs. CTLs were tested for proliferation, cytokine release (IFNγ), activation markers and cytotoxicity against human breast adenocarcinoma cell lines. The cytotoxic effect of those CTLs was higher against MCF7 human cell line than against MDA-MB-231 human cell line.

HBsAg体外冲击的慢性乙肝患者树突状细胞的生物学特性及其对HBV特异性CTL的诱导作用

目的 :研究HBsAg冲击的慢性乙肝患者单核细胞来源的树突状细胞 (DCs)的功能状况及体外对HBV特异性CTL的诱导作用 ,初步探讨诱导特异性抗HBV细胞免疫的途径。方法 :分离慢性乙肝患者外周血单核细胞 ,以GM CSF +IL 4 +TNF α培养诱导DCs,加入HBsAg冲击以诱导HBV特异性DCs。采用FCM测定细胞表面免疫分子CD1a、CD83、CD86、CD80、CD4 0以及HLA DR的表达水平 ,ELISA法检测培养上清中细胞因子IL 6、IL 12的分泌含量 ,MTT法测定DC刺激同种异体淋巴细胞增殖的能力 ,LDH法检测DC诱导的患者外周血T细胞对HepG2 2 2 15 (转染HBVDNA)、HepG2肝癌细胞株及K5 6 2白血病细胞株的细胞毒作用。结果 :HBsAg冲击的DC其表达CD1a、CD83、CD86、CD80、CD4 0、HLA DR表面分子明显高于对照组 (P <0 0 1,P <0 0 5 ) ,分泌IL 12的水平也高于对照组 (P <0 0 1) ,而分泌IL 6的水平则较对照组显著降低(P <0 0 1) ;HBsAg冲击的DC刺激同种异体淋巴细胞增殖的能力明显增强 (P <0 0 5 ) ,并可有效地诱导自体CTL对转HBV基因的HepG2 2 2 15细胞高效特异性杀伤作用 (P <0 0 1)。结论 :慢性乙型肝炎患者单核细胞来源的DCs经HBsAg抗原冲击后 ,生物学活性增强 ,并且能有效地诱导对HBV特异性反应的CTL。

自体宫颈癌-树突细胞疫苗激活的CTL杀伤效应

背景与目的:树突细胞(dendriticcells,DC)是目前已知的功能最强的抗原递呈细胞(antigen-presentingcell,APC),它可以在体内、外向T淋巴细胞递呈抗原,并诱发细胞毒T淋巴细胞(cytotoxicTlymphocyte,CTL)反应。本研究旨在探讨负载自体宫颈癌抗原的DC体外激发的CTL对自体宫颈癌细胞的杀伤效应。方法:先冻融宫颈癌细胞制备抗原,然后以GM-CSF、IL-4诱导自体外周血单个核细胞(peripheralbloodmononuclearcell,PBMC)获得DC并负载抗原,刺激自体T淋巴细胞制备宫颈癌抗原特异性CTL,观察CTL对宫颈癌细胞的杀伤活性。结果:负载自体宫颈癌抗原DC诱导的特异性CTL对自体宫颈癌细胞的体外杀伤率高达79.32%～89.27%,显著高于淋巴因子激活的杀伤细胞(lymphokine-activatedkillingcells,LAK)的杀伤率(t≥2.89,P<0.05);且对宫颈癌HeLa细胞株具有一定杀伤效应(40.35%～58.09%),但低于自体癌细胞组(t≥2.97,P<0.05);特异性CTL对HepG2、MCF7、A549、MGC803细胞无明显杀伤效应。结论:自体宫颈癌-树突细胞疫苗体外诱导的CTL具有高效而特异的抗自体宫颈癌细胞免疫活性,可望成为宫颈癌生物治疗的一个有力手段。

中国人群流行的乙型肝炎病毒特异性CTL表位特点分析

目的研究中国人群中流行的乙型肝炎病毒(HBV)基因型B型和C型特异性CTL表位的序列特点。方法以国外文献报道的13个HBV的CTL表位氨基酸序列为参考序列,分析其与GenBank下载的45条及作者从乙型肝炎病人血清中扩增的另外5条B型或C型CTL表位氨基酸序列的差别。结果与参考序列相比,本研究分析的B型和C型HBV特异性CTL表位氨基酸序列变异发生频率较高。在本研究分析的13个表位中,变异发生率超过70%的表位在B型HBV有4个,分别是表位FLLTRILTI(A0201,S183-191)、VLQAGFFLL(A0201,S188-196)、ILSPFLPLL(A0201,S382-390)和FLPSDFFPSV(A0201,C18-27),C型HBV有2个,分别是表位ILSPFLPLL(A0201,S382-390)和FLPSDFFPSV(A0201,C18-27)。其中文献中研究最多的HBcAg表位18-27(FLPSDFFPSV),在我国流行的B型和C型HBV中表位的变异率分别高达71%和97%。结论中国人群流行的B型和C型HBV特异性CTL表位与国外文献报道的CTL表位相比在大多数位点上都出现变异,并且不同表位的变异率差异很大,在检测CTL数量和功能时应根据这一特点设计实验。

胞质转导肽-HBcAg_(18-27)-Tapasin诱导C57BL/6小鼠T淋巴细胞分泌Th1型细胞因子及HBV特异性CTL的表达

目的观察融合蛋白胞质转导肽(CTP)-HBcAg18-27-Tapasin诱导C57BL/6小鼠T淋巴细胞分泌Th1型细胞因子及HBV特异性细胞毒T淋巴细胞(CTL)的表达。方法 C57BL/6小鼠随机分为实验组CTP-HBcAg18-27-Tapasin、对照组CTP-HBcAg18-27、HBcAg18-27-Tapasin及空白组(生理盐水)。经肌肉免疫小鼠,ELISA检测T淋巴细胞分泌细胞因子;流式细胞术(FCM)检测T淋巴细胞内的细胞因子;CCK-8法检测T淋巴细胞增殖活性。结果实验组能有效刺激小鼠T细胞分泌Th1型细胞因子;FCM检测实验组融合蛋白诱导的CTL水平明显高于其他组;且实验组T淋巴细胞增殖活性明显高于对照组及空白组。结论 CTP-HBcAg18-27-Tapasin融合蛋白免疫C57BL/6小鼠后,能提高T淋巴细胞增殖活性,能有效刺激T淋巴细胞分泌Th1型细胞因子及增加CTLs的表达。

结核杆菌抗原Ag85C的HLA-A*0201限制性CD8^+CTL表位的预测及鉴定

目的:预测及鉴定结核杆菌(Mycobacterium tuberculosis,Mtb)抗原Ag85C的HLA-A*0201限制性CD8+CTL表位,为基于表位的结核疫苗研究提供依据。方法:应用SYFPEITHI数据库预测结核杆菌抗原Ag85C序列中可能存在的HLA-A*0201限制性T细胞表位,利用T2细胞株分析各预测的抗原肽与HLA-A*0201分子的亲合力,选取高亲合力肽诱导特异性CTL细胞,检测各高亲合力肽刺激其特异性CTL细胞分泌的IFN-γ水平、在体外的CTL增殖反应以及细胞杀伤毒性,逐步鉴定出Ag85C的HLA-A*0201限制性CD8+CTL表位。结果:SYFPEITHI数据库从Ag85C序列中预测到14条能够结合HLA-A*0201分子的抗原肽,其中3个抗原肽(170～178 aa、317～325 aa和144～153 aa)显示与T2细胞上HLA-A*0201分子有高结合力,而抗原肽FLTREMPAWL(144～153 aa)能够诱导大多数HLA-A*0201阳性结核患者及PPD(+)健康志愿者产生特异性CTL细胞,并分泌大量的IFN-γ,能够诱导CTL体外发生增殖,能够产生特异性杀伤活性。结论:成功鉴定出抗原肽FLTREMPAWL(144～153 aa)结核杆菌抗原Ag85C的HLA-A*0201限制性CD8+CTL表位,可作为结核疫苗设计的候选表位,为进一步研发新型有效的抗结核疫苗奠定了基础。

穿心莲二萜类化合物对B16细胞致敏小鼠CTL杀伤活性的影响

目的研究穿心莲二萜类化合物(DAP)对B16细胞致敏小鼠脾脏CTL杀伤活性的影响。方法将♂BALB/c小鼠分为对照组、致敏组、50mg·kg-1及150mg·kg-1DAP给药组,制备小鼠脾脏淋巴细胞悬液,流式细胞术分析T淋巴细胞亚群,乳酸脱氢酶(LDH)法和DiO/PI双染色法分别测定CTL杀伤活性。结果50mg·kg-1及150mg·kg-1DAP口服给药可以增加B16细胞致敏小鼠脾脏淋巴细胞中T细胞及CD8+T细胞比例,降低T细胞中CD4+/CD8+比值并增强CTL对B16细胞的杀伤活性。结论DAP可增加B16细胞致敏小鼠脾脏T细胞比例及提高CTL杀伤活性。

HLA-A^＊0201限制性CTL表位肽的三维定量构效关系的研究

运用比较分子力场 (CoMFA)和比较分子相似性指数分析 (CoMSIA)方法研究了 5 0个HLA A 0 2 0 1限制性CTL表位九肽结构与亲和性间的关系 ,另外 15个表位九肽作为预测集用于检验模型的预测能力 .结果表明采用CoMSIA得到的构效关系模型 (q2 =0 .62 8,r2 =0 .997,F =840 .419)要明显优于采用CoMFA得到的构效关系模型 .在CoMSIA计算中 ,当引入疏水场时 ,三维构效关系模型得到明显改善 ,通过该三维构效关系模型 ,可较精确地估算预测集中 15个CTL表位肽与HLA A 0 2 0 1间的亲和力 (r2pred=0 .743 ) .通过分析分子场等值面图在空间的分布 ,可以观察到表位肽分子周围的立体及疏水特征对表位肽与HLA A 0 2 0 1间结合亲和力的影响 ,从而为进一步对CTL表位肽进行结构改造并基于此进行治疗性疫苗分子设计提供理论基础 .