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1.
We report here development of hypoglycaemia in the convalescent phase of Japanese encephalitis virus (JEV) infection in mice by the induction of antigen-specific Ly12+ T cells in the spleen which mediate hypoglycaemia through the generation of soluble T cell hypoglycaemic factor (TCHF). The TCHF acted in a dose-dependent manner and was found to be trypsin-sensitive and thermolabile. It was purified on Superose-12 high performance liquid chromatography (HPLC) gel filtration column and purified protein migrated as a ~25-kD band on SDS–PAGE. The JEV-induced hypoglycaemia coincided with an increased circulating glucagon level, without any alterations in blood insulin and growth hormone concentrations. These effects were mimicked by TCHF. These results indicate that JEV-primed T lymphocytes mediate hypoglycaemia through the production of a soluble hypoglycaemic factor.  相似文献   

2.
During dengue type 2 virus (DV) infection of mice a unique cytokine, the cytotoxic factor (CF), is produced which reproduces the pathological lesions seen in patients of dengue haemorrhagic fever (DHF). Recently we have observed a CF-like protein in the sera of DHF cases. The present study was undertaken to investigate whether DV can stimulate human peripheral blood mononuclear cells (PBMC) in vitro to produce human CF (hCF). Cultures prepared from PBMC or its enriched subpopulations were inoculated with 1000 LD50 of DV and controls with normal mouse brain suspension (NMB). Aliquots of cultures were harvested daily from 24 h to 96 h and their supernatant (CS) and cells were separated. CS were screened for viral titres and for the presence of hCF by cytotoxicity assay, inhibition ELISA, dot blot and Western blot tests using anti-mouse-CF antibodies. The RNA from the cells was screened in Northern blot and dot blot tests for the presence of mRNA for CF. It was observed that hCF appeared in the CS of DV-infected culture of PBMC and T-enriched cells at 48 h and was present until 96 h; no CF was detected in CS of B cells or monocyte cultures. The production of hCF was abrogated by pretreatment of the T cells with anti-CD4 antibodies but not with anti-CD8 antibodies, indicating that hCF was produced by CD4+ T cells. The Northern blot analysis using oligonucleotide probes prepared on the basis of amino-terminal sequence of mouse CF, showed presence of mRNA for hCF in PBMC and T cell cultures. DV replicated in PBMC cultures with peak titres at 48 h. The findings of the present study demonstrate that DV-induced hCF is produced by human T cells.  相似文献   

3.
Influenza virus and respiratory syncytial virus (RSV) are the most common causes of acute severe respiratory infection in children during the winter. There have been few reports about peripheral blood T cell activation in vivo in influenza virus infection and conflicting results concerning peripheral blood T cells activation in RSV infection. Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4, CD152) is a receptor present on T cells that plays a critical role in the down-regulation of antigen-activated immune responses. To clarify the status of peripheral blood T cells, we investigated intracellular CTLA-4 expression in T cells in patients with influenza virus and RSV infection. We collected blood samples from 15 patients with influenza virus infection, including three with complications of influenza virus-associated encephalopathy and 18 patients with RSV infection, as well as 44 healthy children. We determined the intracellular expression of CTLA-4 in CD4+ and CD8+ T cells by flow cytometry. There were no significant differences in the percentages of intracellular CTLA-4-positive CD4+ T cells and CD8+ T cells by age. The percentages of intracellular CTLA-4-positive CD4+ T cells in the patients with influenza virus infection were significantly higher than those in healthy children (P < 0.01). In particular, the patients with influenza virus-associated encephalopathy had sevenfold higher percentages of CTLA-4-positive CD4+ T cells than influenza patients without encephalopathy (P < 0.05). The patients with influenza virus-associated encephalopathy had increased percentages of CTLA-4-positive CD8+ cells at the acute stage in comparison with the convalescent stage and in control subjects (P < 0.01, respectively). RSV patients showed no increase in CTLA-4-positive CD4+ T cells or CD8+ T cells. The immunological status of peripheral T cell activation is substantially different in influenza virus infection and RSV infection. The patients with RSV infection did not show any increase in CTLA-4-positive peripheral blood T cells. There was a remarkable increase in intracellular CTLA-4 in CD4+ and CD8+ T cells in influenza virus-associated encephalopathy. Down-regulation of antigen-activated peripheral blood T cell activation might play an important role in the pathogenesis of influenza virus-associated encephalopathy and host defence against influenza virus infection.  相似文献   

4.
CD4+CD25+ T regulatory cells may play a role in the different clinical presentations of chronic hepatitis C virus (HCV) infection by suppressing CD4+ T cell responses. Peripheral CD4+CD25+ T cells from chronic HCV carriers with normal and abnormal alanine aminotransferase (ALT) were analysed for specificity and effect on HCV-specific CD4+ T cell reactivity by flow cytometry for intracellular cytokine production and proliferation assay. HCV-specific CD4+CD25(+high) T cells consistently produced transforming growth factor (TGF)-beta but only limited amounts of interleukin (IL)-10 and no IL-2 and interferon (IFN)-gamma. The HCV-specific TGF-beta response by CD4+CD25(+high) T cells was significantly greater in patients with normal ALT compared to patients with elevated ALT. In addition, a significant inverse correlation was found between the HCV-specific TGF-beta response by CD4+CD25(+high) T cells and liver inflammation. In peripheral blood mononuclear cells (PBMC), both HCV antigen-induced IFN-gamma production and proliferation of CD4+ T cells were greater in patients with elevated ALT compared with patients with normal ALT. Depletion of CD4+CD25+ cells from PBMC resulted in an increase of both IFN-gamma production and proliferation of HCV-specific CD4+ T cells that was significantly greater in patients with normal ALT levels compared with patients with elevated ALT. In addition, CD4+CD25+ T cells from patients with normal ALT levels proved to be significantly more potent to suppress CD4+ T cell reactivity with respect to those from patients with elevated ALT. In conclusion, these data support the hypothesis that CD4+CD25+ cells may play a role in controlling chronic inflammatory response and hepatic damage in chronic HCV carriers.  相似文献   

5.
观察子宫内膜异位症患者外周血单个核细胞CD4~+CD25~+Foxp3~+调节性T细胞的数量变化,初步探讨其意义。采用流式细胞术检测20例健康对照者(对照组)及46例子宫内膜异位症患者(疾病组临床r-AFS分期:Ⅰ~Ⅱ期26例,Ⅲ~Ⅳ期20例)外周血单个核细胞(PBMC)中CD4~+CD25~+Foxp3~+调节性T细胞数目,并计算CD4~+CD25~+Foxp3~+调节性T细胞占CD4~+T淋巴细胞的百分率;分析不同分期子宫内膜异位症患者外周血CD4~+CD25~+Foxp3~+调节性T细胞的变化。结果显示,与健康对照组相比,疾病组PBMC中CD4~+CD25~+Foxp3~+Treg占CD4~+T淋巴细胞的百分率及CD4~+CD25~+Foxp3~+Treg绝对数均明显升高(P<0.01,P<0.05);疾病组中,Ⅲ~Ⅳ期的PBMC中CD4~+CD25~+Foxp3~+Treg占CD4~+T淋巴细胞的百分比及CD4~+CD25~+Foxp3~+Treg绝对值较Ⅰ~Ⅱ期均明显升高(P<0.01,P<0.05)。提示子宫内膜异位症患者外周血CD4~+CD25~+Foxp3~+调节性T细胞数目和比例增多,可能存在自身免疫调节功能的紊乱,且与病程发展紧密相关。  相似文献   

6.
目的:观察肺癌患者外周血调节性T细胞的变化,并探讨CpG ODN的干预作用。方法:分离肺癌患者和健康志愿者(各30例)的外周血单个核细胞(PBMC),用流式细胞仪检测CD4+CD25+调节性T细胞比例,Real-time PCR检测Foxp3基因的表达,ELISA法检测TGF-β和IFN-γ水平。将30例肺癌患者的PBMC随机分为实验组和安慰剂组,分别给予CpG ODN2006或安慰剂CpG ODN1612干预,比较干预前后上述指标的变化。结果:肺癌患者PBMC中的CD4+CD25+调节性T细胞比例、Foxp3基因的相对表达量、TGF-β水平均高于健康对照组,差异具有显著性,但不同病理分型和分期的肺癌患者亚组间比较无显著性差异。两组的IFN-γ水平比较无差异性。CpG ODN干预后CpG ODN2006治疗组的CD4+CD25+调节性T细胞比例、Foxp3基因的相对表达量及TGF-β水平出现了下降,差异有显著性,IFN-γ水平变化无显著性差异。而CpG ODN1612安慰剂组的上述指标在干预前后则无显著性改变。结论:肺癌患者外周血中的CD4+CD25+Foxp3+调节性T细胞比例、TGF-β水平明显升高。CpG ODN2006干预可下调CD4+CD25+Foxp3+调节性T细胞比例及TGF-β水平。  相似文献   

7.
Memory cross‐reactive CD8+ T‐cell responses may induce protection or immunopathology upon secondary viral challenge. To elucidate the potential role of T cells in sequential flavivirus infection, we characterized cross‐reactive CD4+ and CD8+ T‐cell responses between attenuated and pathogenic Japanese encephalitis virus (JEV) and pathogenic West Nile virus (WNV). A previously reported WNV NS4b CD8+ T‐cell epitope and its JEV variant elicited CD8+ T‐cell responses in both JEV‐ and WNV‐infected mice. The peptide variant homologous to the immunizing virus induced greater cytokine secretion and activated higher frequencies of epitope‐specific CD8+ T cells. However, there was a virus‐dependent, peptide variant‐independent pattern of cytokine secretion; the IFNγ+‐to‐IFNγ+TNFα+ CD8+ T‐cell ratio was greater in JEV‐ than in WNV‐infected mice. Despite similarities in viral burden for pathogenic WNV and JEV viruses, CD8+ T cells from pathogenic JEV‐immunized mice exhibited functional and phenotypic profiles similar to those seen for the attenuated JEV strain. Patterns of killer cell lectin‐like receptor G1 (KLRG1) and CD127 expression differed by virus type, with a rapid expansion and contraction of short‐lived effector cells in JEV infection and persistence of high levels of short‐lived effector cells in WNV infection. Such cross‐reactive T‐cell responses to primary infection may affect the outcomes of sequential flavivirus infections.  相似文献   

8.
9.
目的 采用T细胞表位预测软件结合体外实验鉴定丙型肝炎病毒(HCV)特异性细胞毒性T细胞(CTL)表位.方法 采用T表位预测软件Rankpep预测HCV特异性CTL表位,选择候选CTL表位加以合成;用候选CTL表位肽分别刺激HCV感染者以及健康志愿者的外周血单个核细胞(PBMC),采用酶联免疫斑点试验(ELISPOT)检测PBMC中肽特异性分泌IFN-γ的斑点形成细胞(spots forming cells,SFC)的水平,采用细胞内细胞因子染色(intracellular cytokine staining,ICS)检测PBMC中肽特异性IFN-γ+CD8+T细胞的水平.结果 用5条候选CTL表位肽[NS3 450(TVPQDAVSR)、NS3 594(GPTPLLYRL)、NS4b 78(SMMAFSAAL)、NS5a 416(SEENVSVVF)和NS5a 367(TVSSALAEL)]分别刺激10个HCV感染者和2个健康者的PBMC后,健康者的PBMC不产生IFN-γ而7个HCV感染者的PBMC产生IFN-γ;HCV感染者的PBMC中肽特异性分泌IFN-γ的细胞的频率为(5-36)SFC/105 PBMC,肽特异性IFN-γ+CD8+T细胞占总CD8+T细胞的百分比为0.02%~0.25%.结论 ELISPOT结果和ICS结果证实5条肽NS3 450、NS3 594、NS4b 78、NSSa 416和NS5a 367为全新的HCV特异性CTL表位.  相似文献   

10.
CD3- and CD28-activated T cells expanded for 12 days ex vivo to produce suicide gene-modified T cells are hyporesponsive to alloantigens. To investigate whether this impaired alloreactivity is a result of preferential expansion of regulatory T (Treg) cells, we compared peripheral blood mononuclear cells (PBMC) activated with CD3 and CD28 antibodies co-immobilized on beads and expanded for 12 days with interleukin (IL)-2 (Co(CD3/CD28) cells) to the respective unactivated PBMC in terms of proliferation, cytokine production, and expression of Treg markers [cytotoxic T-lymphocyte antigen 4 (CTLA4), glucocorticoid-induced tumour necrosis factor receptor (GITR) and forkhead box P3 (FoxP3)] after allostimulation. Alloreactive cells were identified by carboxyfluoresceine succinimidyl ester staining dilution. Alloreactive cells in Co(CD3/CD28) cells had a lower proliferative response and a lower potential for IL-2 and interferon-gamma secretion than did those in PBMC, demonstrating a functional impairment of alloreactive cells during ex vivo expansion. Expression of Treg markers transiently increased during ex vivo expansion and was unaffected by depletion of CD25(+) cells (containing Treg cells) before ex vivo PBMC expansion. Such prior CD25(+) depletion did not restore the alloreactivity of Co(CD3/CD28) cells. After allostimulation, expression of Treg markers was restricted to proliferative (alloreactive) cells among PBMC or Co(CD3/CD28) cells. Lastly, CD4(+) CD25(+) cells purified from Co(CD3/CD28) cells lacked suppressive activity when used as a third party, in contrast to CD4(+) CD25(+) cells purified from PBMC. In conclusion, the impaired alloreactivity of T cells expanded ex vivo is not a result of preferential Treg cell expansion and/or enhanced suppressive Treg activity.  相似文献   

11.
We recently demonstrated that a unique HIV-1-infected nonprogressor was infected with a nonevolving replication-incompetent HIV-1 strain, showing a total absence of viral evolution in vivo. Potent immune responses against HIV-1 were observed in his PBMC, despite an apparent lack of viral replication for at least 8 years. His PBMC resisted superinfection with CCR5, CXCR4, and dual-tropic HIV-1 strains, although highly purified CD4+ T cells supported infection, but without any visible cytopathic effect. Potent noncytolytic CD8+ T cell antiviral activity was shown to protect his PBMC from productive infection. This activity was not mediated by several known chemokines or IFN-gamma, which were produced at high levels after PHA activation of his CD8+ T cells, indicating the action of other CAF-like CD8 factors. This antiviral activity was a memory response, induced by HIV-specific stimulation to similar levels observed by PHA stimulation, but absent in ex vivo resting T cells. Immunological mechanisms associated with this antiviral suppressive activity included vigorous Gag-specific helper T cell proliferative responses and high-level IFN-gamma release by both CD4 and CD8 T cells. These responses were broadly directed against multiple Gag epitopes, both previously reported and some novel epitopes. Strong HIV-specific helper T cell function was also associated with strong neutralizing antibodies. Understanding how to induce these protective immune responses in other individuals could provide a major step forward in the design of effective immunotherapies or vaccines against HIV infection.  相似文献   

12.
Interferon (IFN) alpha and gamma were measured by radio-immunoassays in supernatants from cultures of peripheral blood mononuclear cells (PBMC) or purified T cell subsets incubated with either Plasmodium falciparum schizont-enriched malaria antigen (mAg), uninfected red blood cells (RBC) or pokeweed mitogen (PWM). Cell donors were 24 clinically immune, healthy African adult native residents of a P. falciparum-endemic region, Haut-Ogooué, Gabon, and seven non-immune, European temporary residents with a history of a single to a few malaria infections during the previous 1 to 9 months. When PBMC were cultured in medium alone or with RBC antigen no or low titres of IFN-gamma were detected. PBMC proliferation and IFN-gamma production observed in the presence of mAg were dose dependent and significantly correlated. When cultured with mAg, PBMC from non-immune Europeans produced significantly higher levels of IFN-gamma than did PBMC from clinically immune Africans. No such difference was found when PBMC were cultured with PWM. The mAg-induced IFN-gamma production was due mainly to CD4+ T cells and was not enhanced by CD8+ T cell depletion. No IFN-alpha was detected in culture supernatants. Thus, P. falciparum antigens are able to induce in vitro production of IFN-gamma by CD4+ T cells; however, in this sample, individuals considered to be clinically resistant to malaria were low producers of IFN-gamma.  相似文献   

13.
14.
We have reported recently that mouse liver NK cells and NK1 x 1+ T cells were activated by bacterial superantigens via the IL-12 production from Kupffer cells. In the present study, we examined the effect of staphyloccoccal enterotoxin A (SEA) on human T cells with NK cell markers, CD56 or CD57 (NK-type T cells). After stimulating peripheral blood mononuclear cells (PBMC) with SEA, PBMC produced a large amount of IFN- and acquired a potent antitumour cytotoxicity. The in vitro depletion of either CD56+ TCR NK cells, CD56+ T cells or 57+ T cells from PBMC significantly inhibited the IFN- production from PBMC. When purified NK-type T cells, NK cells and regular T cells were cultured with monocytes and SEA they all produced IFN-, while the IFN- amounts produced by both NK-type T cells were greater than those produced by NK cells. NK cells as well as CD56+ T cells showed cytotoxicity against NK-sensitive K562 cells, whereas both NK-type T cells showed a more potent cytotoxicity against NK-resistant Raji cells than did NK cells. The IFN- production from each population as well as from whole PBMC was greatly inhibited by anti-IL-12 antibody but not by anti-IL-18 antibody. The antitumour cytotoxicity of whole PBMC was also significantly inhibited by anti-IL-12 antibody while the SEA-induced proliferation of PBMC was not affected by anti-IL-12 antibody. Furthermore, SEA-activated NK-type T cells as well as NK cells showed cytotoxicities against vascular endothelial cells. Our findings suggest that human NK-type T cells are thus involved in bacterial superantigen-induced immune response.  相似文献   

15.
16.
Control of human thyroid autoantibody production in SCID mice.   总被引:1,自引:2,他引:1       下载免费PDF全文
In order to determine the phenotype of the cells required for thyroid autoantibody production, peripheral blood mononuclear cells (PBMC) from patients with autoimmune thyroid disease (AITD) were transferred to severe combined immunodeficient (SCID) mice. The production of human IgG, thyroglobulin (Tg) antibody and thyroid peroxidase (TPO) antibody in the SCID recipients was monitored for up to 4 months. PBMC from 10 of 13 AITD patients produced substantial IgG (> or = 100 micrograms/ml) and detectable Tg and TPO antibodies in recipient mice. PBMC pretreated to deplete or enrich T cells produced low or undetectable thyroid-specific antibody in SCID mice. Depletion of CD4+ T cells resulted in much lower or undetectable IgG, Tg and TPO antibodies compared with levels seen in recipients of control PBMC. By contrast, depletion of CD8+ T cells from the PBMC had no overall effect on autoantibody production, although with PBMC from some patients CD8+ depletion possibly enhanced both IgG and autoantibody production. In eight of 10 experiments, autoantibody levels reached maximal titres before total IgG levels peaked. It is considered that thyroid autoantibodies are produced from memory B cells activated in SCID mice and that this activation is T cell- and CD4+ T cell-dependent.  相似文献   

17.
Some patients undergoing bone marrow transplantation (BMT) persistently present increased proportions of circulating CD57+ T cells. We analysed the cell surface phenotype in peripheral blood mononuclear cells (PBMC) from 69 allogeneic and 11 autologous BMT recipients. In parallel samples from 49 patients, the proliferative response to T cell mitogens was assessed, either in the presence or absence of exogenous interleukin-2 (IL-2). PBMC samples from long-term allogeneic BMT patients with increased proportions of CD57+ cells displayed significantly (P less than 0.001) lower proliferative responses, compared with samples from patients with normal proportions of CD57+ cells and from healthy subjects. Elimination of the CD57+ population by C'-dependent lysis did not normalize the proliferative response. After positive selection by cell sorting, CD57+ cells responded poorly, but in the presence of IL-2 the proliferation appeared to be similar to that displayed by the CD57- subset and still suboptimal compared with normal controls. These data suggest that the hyporesponsiveness to mitogenic stimuli in the presence of exogenous IL-2 of PBMC from allogeneic BMT recipients cannot be simply attributed either to the putative suppressor activity of CD57+ cells, or to a poor proliferative capacity of this subset. Supporting this notion we report that PBMC from long-term autologous BMT recipients containing high proportions of CD57+ T cells respond normally to T cell mitogens.  相似文献   

18.
Wen JS  Jiang LF  Zhou JM  Yan HJ  Fang DY 《Virus research》2008,132(1-2):42-48
In this study, we tried to identify dengue virus-specific CD4(+) T-cell epitopes, which can induce PBMC (peripheral blood mononuclear cells) isolated from DF convalescent patients (dengue virus type 1 infection) to secrete IFN-gamma. PBMC of DF convalescent patients were stimulated in vitro with dengue virus-derived peptides, which were prepared based on the prediction of dengue virus-specific CD4(+) T-cell epitopes by using RANKpep online software. Subsequently, the frequency of IFN-gamma producing T cells and percentage of IFN-gamma(+) CD4(+) T cells were measured by using ELISPOT assay and ICS assay (intracellular cytokine straining), respectively. The positive response of PBMC by ELISPOT showed that the numbers of SFC (spots forming cells) ranged from 50 to 310 SFC/1x10(6) PBMC. The positive response of PBMC by ICS assay showed that the percentage of IFN-gamma(+) CD4(+) T cells ranged from 0.03 to 0.27%. As a result, C(45-57) (KLVMAFIAFLRFL), E(396-408) (SSIGKMFEATARG), NS3(23-35) (YRILQRGLLGRSQ), and NS3(141-155) (NREGKIVGLYGNGVV) were identified as dengue virus-specific CD4(+) T-cell epitopes.  相似文献   

19.
The importance of the enzyme-linked immunosorbent spot (ELISPOT) assay as a tool for studying immune responses in vitro is becoming increasingly apparent. However, there remains a need for enhanced sensitivity for the detection of low frequency antigen-specific T cell responses. We reasoned that the addition of a combination of the cytokines interleukin (IL)-7 and IL-15 would selectively increase interferon-gamma (IFN-gamma) production from antigen-stimulated CD4+ and CD8+ effector memory T cells. Freshly isolated or cryopreserved peripheral blood mononuclear cells (PBMC) from four healthy donors were analysed by ELISPOT for the frequency of purified protein derivative (PPD)-specific CD4+ T cells or cytomegalovirus (CMV) peptide-specific CD8+ T cells. Addition of IL-7 and IL-15 increased the number of PPD-specific CD4+ T cells up to 2.4-fold in fresh PBMC and up to 18-fold in cryopreserved PBMC. The cytokines also increased the number of CMV peptide-specific CD8+ T cells in fresh PBMC up to 7.5-fold. No additional increases were seen when antibodies to co-stimulatory molecules CD28 and CD49d were applied together with the cytokine combination. These data demonstrate that the sensitivity of the ELISPOT assay may be significantly augmented by addition of the cytokines IL-7 and IL-15 to antigen-stimulated cells. This method will be particularly useful for the assessment of antigen-stimulated cytokine production by T cells in cryopreserved biological specimens.  相似文献   

20.
为研究Graves病患者外周血T细胞亚群及共刺激分子的表达 ,并探讨其在Graves免疫病理机制中的作用 ,本文采用免疫荧光标记和流式细胞仪术检测了 19例Graves病患者和 11例正常人外周血T细胞亚群及共刺激分子 (CD2 8、B7、CD40、CD40L、 4 1BB、OX40 )的表达。结果表明 ,19例初诊Graves病患者外周血T细胞亚群呈现异常改变 ,表现为CD3+ 和CD4+T细胞显著下降 (P <0 0 5 ,P <0 0 1) ,CD4+ /CD8+ T细胞比值倒置 (P <0 0 1) ,共刺激分子CD2 8在T细胞中的表达水平明显下降 (P <0 0 1) ,T细胞亚群CD4+ CD2 8+ 、CD8+ CD2 8+ 细胞数量均减少 (P <0 0 5 ,P <0 0 1) ,而 4 1BB分子表达显著地升高 (P <0 0 5 )。随防 10例治疗后缓解患者 ,T细胞亚群失衡明显改善 ,共刺激分子CD2 8的表达水平上调 (P <0 0 1) ,而4 1BB分子的表达明显下降 (P <0 0 1) ,T细胞亚群CD4+ CD2 8+ 、CD8+ CD2 8+ 细胞数量均增加 (P <0 0 1) ,甲状腺自身抗体甲状腺球蛋白抗体 (TGAb )和甲状腺微粒体抗体 (TMAb )的表达水平均下降 (P <0 0 1,P <0 0 1)。从而表明 ,T细胞亚群的异常及共刺激分子CD2 8、 4 1BB的表达改变与Graves病的免疫病理机制相关。  相似文献   

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