HFRS患者汉滩病毒核蛋白特异性CTL克隆的建立及其初步研究

为探讨汉滩病毒核衣壳蛋白 (HTNV NP )诱生的特异性细胞免疫的分子基础 ,为阐明HFRS的发病机制和疫苗的设计提供资料 ,本文分离HFRS患者的PBMC ,建立HTNV NP特异性的CTL克隆 ,同时将克隆有HTNVS基因不同片段的真核表达载体转染患者自身的B淋巴母细胞系 (BLCL ) ,建立CTL靶细胞系 ,并进行细胞杀伤试验。建立的特异性CTL克隆对表达完整NP、NP羧基和氨基端肽段的靶细胞均有比较明显的杀伤效应 ,平均杀伤率分别为 5 0 2 %、 39 0 %和 2 5 8%。表明HTNV NP优势T细胞表位可能主要位于病毒核蛋白的羧基端     

我国疫区HFRS患者汉滩病毒核蛋白特异性CTL克隆的建立

目的：探讨汉滩病毒核衣壳蛋白（HTNV-NP）诱生的特异性细胞免疫的分子基础，阐明HFRS的发病机理。方法：分离HFRS患者的PBMC，建立HTNV-NP特异性的CTL克隆，同时将克隆有HINV S基因不同片段的真核表达载体转染患者自身的B淋巴母细胞系（BLCL），建立CTL靶细胞系，并进行细胞杀伤试验。结果：建立的特异性CTL克隆对表达完整NP、NP羧基和氨基端肽段的靶细胞均有比较明显的杀伤效应，平均杀伤率分别为50.2%、39.0%和25.4%。结论：NTNV-NP优势T细胞表位可能主要位于病毒核蛋白的羧基端。     

CTL对同种异体靶细胞杀伤作用的实验研究

目的：研究特异性CTL杀伤的效应与HLA型别之间的关系。方法：用已知型别的EB病毒转化的B淋巴母样细胞（Epstein-Barr-transformed B lymphoblastoid cell line,EBV-LCL）与同种异体外周血单个核细胞（PBMC）共培养，激活同种异体抗原特异性细胞毒性T细胞（cytotoxicity T cell,CTL），然后利用同位素释放法观察CTL对HLA－I类表型不同的EBV－LCL的杀伤活性。结果：用EBV－LCL－1刺激自身PBMC－1所诱翌的CTL－1a，只能杀伤EBV－LCL－1，而不能杀伤HLA－I类表型不同的EBV－LCL－2；但用EBV－LCL－2刺激PBMC－1所诱导的CTL－1b，却能有效杀伤HLA－I类表型不同的EBV－LCL－2。结论：①MHC表型不同的免疫细胞之间可以发生相互作用；②TCR既不单独识别靶细胞表面的抗原肽，也不直接识别靶细胞表面的MHC分子（MHC特异性抗 原决定簇），而是识别MHC－抗原肽复合物的表达综合信息，后者可能是由MHC－抗原肽复合物表面的空间构象、电荷性质及其分布等信息所构成；③所谓CTL的特异性杀伤作用，是MHC－抗原肽复合物表面信息激活该信息性T细胞克隆的结果。     

特异性CTL胞毒作用与HLA型别关系探讨

目的：探讨特异性CTL胞毒作用与靶细胞的HLA型别关系。方法：本实验以特定HLA型别，EB病毒转化的B淋巴母细胞（EBV－LCL）与同种异体单个核细胞（PBMC）混合培养，激活同种抗原特异性细胞性T细胞（CTL），观察其对携带不同HLA型别的EBV－LCL靶细胞的杀伤活性。结果：用EBV－LCL1致敏的效应细胞1对EBV－LCL2的杀伤效应比对EBV－LCL3强，用EBV－LCL2致敏的效应细胞2对EBV－LCL1的杀伤效应比对EBV－LCL3强，用EBV－LCL3致敏的效应细胞3对EBV－LCL1，2几乎无杀伤效应。结论：特异性CTL对不同HLA型别的靶细胞的胞毒作用存在差异，这不仅仅与HLA型别关联，而可能取决于抗原肽与MHC所组成的抗原综合信息。     

HFRS患者BLCL的建立及HTNV S基因片段在其内获得长期稳定的表达

虽然对汉坦病毒核蛋白（HV NP）氨基端蛋白的原核表达产物的抗原性及免疫原性已进行了许多研究，并已用于出血热的诊断，但该抗原表位的精确一级结构及其基因定位迄今尚未完全明确。而研究T细胞表位的前提是首先要构造含病原体抗原基因片段的表达载体质粒。要实现CTL效应细胞对靶细胞的有效杀伤，前提条件之一是效靶细胞必须具有相同的HLA型别。通常选用与效应细胞同源即同一供者的PBMC建立靶细胞，本研究采用与HV特异性CTL同源的患者自身的EB病毒转化的B淋巴母细胞系（EBV—transformed B lymphoblastoid cell line，BLCL）建立靶细胞系，将含有不同汉滩病毒（HTNV）S基因片段的重组真核表达载体转染人BLCL，获得长期稳定表达，为下一步进行CTL杀伤试验提供靶细胞系。     

克隆化的细胞毒性T淋巴细胞的表面分子参与NK的识别

作者为探讨CTL识别过程的本质,建立了在克隆水平上研究T细胞的一种新的溶解特异性产物的方法。作者实验发现,用基因克隆化的干扰素(IFN)作短期(2—5天)处理,小鼠克隆化的CTL不仅能杀伤抗原特异性的靶细胞,也能溶解NK敏感的靶细胞,但不能溶解NK抵抗的靶细胞。若延长培养时间(5天以上),并加入含高浓度     

四聚体技术检测人外周血巨细胞病毒抗原特异性CTL

为深入了解抗病毒免疫机制,探索人在健康状态及巨细胞病毒(CMV)急性感染时抗原特异性细胞毒T淋巴细胞(CTL)数量的动态变化。以CMV抗原肽、HLA-A*0201重链和轻链制备CMV四聚体;分离并检测12名健康被检者外周血单个核细胞(PBMC)中CMV抗原特异CTL数量;PBMC体外培养建立CTL细胞系,于末次刺激的不同时相进行四聚体染色,流式细胞仪(FACS)检测抗原特异CTL数量。结果发现9名被检者PBMC中均检出抗原特异CTL;细胞系中CMV特异性CTL数量急剧增多,细胞系与PBMC相比,差异有显著的统计学意义(P<0.001);研究结果提示,9名被检者感染过CMV,血液中存在少量免疫记忆性T细胞,当再次遭遇同一抗原后发生克隆扩增。     

HIV血清阳性个体中HIV特异性的细胞毒性T淋巴细胞

病毒特异性的细胞毒性T淋巴细胞(CTL)对病毒感染细胞的杀伤作用是宿主抗病毒感染的一种主要机制。本文报导在人免疫缺陷病毒(HIV)感染的个体体内存在有HIV特异性的细胞毒性T淋巴细胞。作者首先建立了实验组和对照组的B淋巴细胞系,其中实验组B细胞来自8例HIV血清阳性的男性同性恋患者,而对照组B细胞来自5例HIV血清阴性个体。然后用HIV-牛痘重组病毒载体感染这些B细胞株,并将其作为靶细胞用于细胞毒活性的测     

EB病毒转化B淋巴母细胞在汉滩病毒CTL表位研究中的应用

目的:建立EB病毒转化B淋巴母细胞系(B-LCL),作为抗原提呈细胞(APC)提呈抗原肽,刺激短期培养的特异性T细胞活化并分泌IFN-γ,从而应用于T细胞表位鉴定中.方法:用B95-8细胞培养上清中的EB病毒转化肾综合征出血热(HFRS)患者PBMC,建立HFRS患者的B-LCL,以自身BLCL为APC,加载抗原肽后,刺激短期培养的G9L特异的HFRS患者CD8+ T细胞系,应用ELISPOT测定CD8+ T细胞受到抗原肽刺激后产生IFN-γ的能力.结果:加载过抗原肽G9L或V15R的B-LCL可刺激G9L特异的CD8+ T细胞活化并产生IFN-γ,而与G9L无同源序列的115P则不能刺激G9L特异的CD8+ T细胞活化.结论:B-LCL可作为非专职APC有效地将抗原肽提呈给特异性T细胞.     

四聚体技术检测人外周血巨细胞病毒抗原特异性OTL

为深入了解抗病毒免疫机制,探索人在健康状态及巨细胞病毒（CMV）急性感染时抗原特异性细胞毒T淋巴细胞（CTL）数量的动态变化.以CMV抗原肽、HLA-A＊0201重链和轻链制备CMV四聚体;分离并检测12名健康被检者外周血单个核细胞（PBMC）中CMV抗原特异CTL数量;PBMC体外培养建立CTL细胞系,于末次刺激的不同时相进行四聚体染色,流式细胞仪（FACS）检测抗原特异CTL数量.结果发现9名被检者PBMC中均检出抗原特异CTL;细胞系中CMV特异性CTL数量急剧增多,细胞系与PBMC相比,差异有显著的统计学意义（P＜0.001）;研究结果提示,9名被检者感染过CMV,血液中存在少量免疫记忆性T细胞,当再次遭遇同一抗原后发生克隆扩增.     

汉滩病毒核蛋白T细胞表位的鉴定及其特异性T细胞应答规律的初步探讨

目的:鉴定引起肾综合征出血热(HFRS)的汉滩病毒核蛋白(HTNV-NP)的T细胞表位,并探讨其特异性T细胞应答的规律。方法:合成覆盖HTNV-NP全长序列的全套部份重叠15肽,用ELISPOT方法筛选能刺激HFRS患者外周血单个核细胞(PBMC)产生IFN-γ的15肽,并测定其特异性T细胞的频率。结果:47例HFRS患者中,有18例可对HTNV-NP产生特异性T细胞应答,并发现在病程的早期就已开始产生T细胞应答。从11例患者PBMC中,鉴定出了17种HTNV-NP特异的T细胞表位,其中14种T细胞表位为首次报道,T细胞表位主要位于NP一级结构的中部。结论:HFRS病程早期即可产生特异性T细胞应答,T细胞表位主要位于NP序列的中部,T细胞应答可能在汉滩病毒感染过程中起重要的免疫保护作用。     

Impaired cytotoxic T lymphocyte response to Epstein-Barr virus-infected NK cells in patients with severe chronic active EBV infection

Clinical evidence of a relationship between severe chronic active Epstein-Barr virus (EBV) infection and clonal expansion of EBV-infected T or NK cells has been accumulated. In order to clarify pathogenesis of EBV-infected cell proliferation in patients with severe chronic active EBV infection, cytotoxic T lymphocyte (CTL) responses of two patients against B-lymphoblastoid cell lines (B-LCL) and EBV-infected NK cells were examined in comparison with those of HLA-identical healthy siblings. Unexpectedly, patients' CTL activities induced by mixed culture with autologous B-LCLs were markedly reduced, although uncontrolled EBV-related B-cell proliferations have never been experienced. In contrast, limiting dilution analysis demonstrated that B-LCL-specific CTL precursor (CTLp) frequencies of patients were comparable to those of their healthy sisters. The existence of normal levels of B-LCL-specific T cell responses was confirmed by flow-cytometric analysis of IFN-gamma-producing T cells after stimulation with B-LCLs. Infected NK-cell-specific CTLp frequencies of the patients were at undetectable levels despite their expression of latent membrane protein (LMP) 1, suggesting mechanisms to escape immunologic surveillance. In the patients' HLA-identical healthy sisters, infected NK-cell-specific CTLps were detected, and infected NK-cell-specific CTL clones could be established. From these findings, two treatment options for severe chronic active EBV infection are offered for consideration: adoptive transfer of in vitro-cultured CTL, and bone marrow transplantation from HLA-identical donors.     

Study on the Cytotoxic T Lymphocytes Clone Specific for the Nucleocapsid Protein of Hantaan Virus from Peripheral Blood in Patients with Hemorrhagic Fever with Renal Syndrome

Hemorrhagic fever with renal syndrome (HFRS) occursmainly in China with a high mortality rate and threatensthe health and life of population, Hantaan virus (HTNV),the prototype member of Hantavirus (HV) genus, causesHFRS in human. In the structural proteins of HV, the nu cleocapsid protein (NP), is associated with the functionsof viral RNA, and is also an important immunogen involv ing in the protective immune responses against infection.The pathogenesis of Hantaan virus infecti…     

Cytotoxic interactions of virus specific effector cells with virus infected targets of different cell type.

The action of Sendai virus specific cytolytic T lumphocytes (CTL) against Sendai virus infected macrophages was found to be H-2 restricted while Sendai virus infected cell lines, including fibroblasts and tumour cells, were lysed across the H-2 barrier to some extent. The properties of the Meth-A tumour cell, which was resistant to lysis by allogenic killer cells was investigated. Sendai virus specific CTL failed to kill Sendai virus infected Meth-A cells but after vaccinia virus infection these target cells were susceptible to lysis by vaccinia virus specific CTL.     

Searching for MHC-restricted anti-viral antibodies: antibodies recognizing the nucleoprotein of influenza virus dominate the serological response of C57BL/6 mice to syngeneic influenza-infected cells

An attempt has been made to generate monoclonal antibodies which recognize the same target structures on influenza-infected cells as those seen by cytotoxic T lymphocyte (CTL) receptors. Such antibodies, if they mimicked the T cell receptor specificity, would be expected to be both virus specific and restricted in their binding by the major histocompatibility complex (MHC) antigens. Approximately 200 hybridomas from C57BL/6 (H-2b) mice primed and boosted with influenza virus (X-31)-infected EL4 (a C57BL/6 T cell lymphoma) were screened for reactivity on infected and uninfected cells of different MHC haplotypes. Of the 10 hybridoma antibodies which were identified as being reactive with X-31-infected EL4, but not uninfected EL4, all reacted equally well with X-31-infected cells of H-2b, H-2d and H-2k haplotypes, indicating a lack of MHC restriction in their recognition of the infected cells. Unexpectedly, 7 of the 10 monoclonal antibodies were found to react specifically with the purified influenza virus nucleoprotein (NP), a predominant viral antigen in CTL recognition of infected cells. Fluorescence-activated flow cytometry confirmed that these antibodies were able to recognize NP serological determinants on the surface of viable, infected cells, but the anti-NP antibodies were unable to block the lytic activity of an NP-specific CTL clone.     

A new model of Hantaan virus persistence in mice: the balance between HTNV infection and CD8(+) T-cell responses

We established a viral persistence model that involves the adoptive transfer of spleen cells from immunocompetent mice (H-2(d)) into Hantaan virus (HTNV)-infected severe combined immunodeficient (SCID, H-2(d)) mice. The infection is maintained despite the presence of neutralizing antibodies, without apparent signs of disease, and there is a correlation between HTNV persistence and the lack of HTNV-specific CD8(+) T cells. In addition, disseminated HTNV infection before the initiation of immune responses appears to be important for virus persistence. The suppression of HTNV-specific CD8(+) T cells in the present model appears to occur at the periphery. The present study also demonstrates that CD8(+) T cells contribute to the clearance of HTNV. Thus, it seems that HTNV-specific CD8(+) T cells play a key role in HTNV persistence in mice. This model of viral persistence is useful for studies of immune responses and immunocytotherapy against viral infection.     

HLA Class-I-Restricted and Colon-Specific Cytotoxic T Cells from Lamina Propria Lymphocytes of Patients with Ulcerative Colitis

We established cytotoxic T-lymphocyte (CTL) lines against colonic epithelial cell line from LPLs of patients with ulcerative colitis by continuous stimulation with human lymphocyte antigen A (HLA-A) matched colonic epithelial cell lines and clones from LPLs using polyclonal stimulation with phytohemagglutinin. The established CTL lines and clones showed cytotoxicity against HLA-A-matched colonic epithelial cell line but not against HLA-mismatched colonic epithelial cell lines, and HLA-A-matched lung and esophagus cell lines. The CTL response was HLA class I-restricted and mediated by CD8-positive T-lymphocytes. Moreover, the CTL line showed cytotoxicity against autologous B-LCLs pulsed with peptides extracted from HLA-A-matched colonic epithelial cell line but not against other organ-derived peptides pulsed and unpulsed autologous B-LCLs. CTL lines and clones established from LPLs of patients with ulcerative colitis showed colon-specific and HLA class I-restricted killing of human colonic epithelial cell line, suggesting that these CTLs may play a role in colonic epithelial cell damage in some patients with ulcerative colitis.     

CYTOTOXIC INTERACTIONS OF VIRUS SPECIFIC EFFECTOR CELLS WITH VIRUS INFECTED TARGETS OF DIFFERENT CELL TYPE*

The action of Sendai virus specific cytolytic T lymphocytes (CTL) against Sendai virus infected macrophages was found to be H-2 restricted while Sendai virus infected cell lines, including fibroblasts and tumour cells, were lysed across the H-2 barrier to some extent. The properties of the Meth-A tumour cell, which was resistant to lysis by allogenic killer cells was investigated. Sendai virus specific CTL failed to kill Sendai virus infected Meth-A cells but after vaccinia virus infection these target cells were susceptible to lysis by vaccinia virus specific CTL.