瘤型麻风动物模型的IL-2测定和T细胞的电镜观察

鼠麻风杆菌(Mycobacterium lepraemurium,MLM)感染的BALB/c小鼠是类似瘤型麻风的动物模型。应用这一模型,作者研究了MLM感染小鼠IL-2产生的动态变化。结果表明,MLM感染小鼠脾细胞IL-2的生成明显低于正常小鼠,二者有显著性差异(p<0.01)。为了探索MLM感染的T淋巴细胞的结构与功能的关系,作者对感染动物的T淋巴细胞作了电镜观察。电镜下发现,感染小鼠脾脏的T淋巴细胞浆内有MLM的存在。本文对以上现象进行了讨论。     

体外扩增的Treg细胞抑制NK细胞介导的抗肿瘤免疫

目的研究CD4+CD25+调节性T细胞(regulatory T cells,Tregs)对NK细胞肿瘤杀伤力的影响及Treg细胞介导的抗肿瘤免疫抑制的机制;初步探讨过继输注NK细胞逆转Treg细胞介导的抗肿瘤免疫抑制的作用。方法免疫磁珠分离法(MACS)分离得小鼠脾脏Treg细胞及NK细胞,用流式细胞术检测其纯度。以CD3/CD28单克隆抗体磁珠和重组小鼠白介素2(rm IL-2)联合刺激体外扩增Treg细胞,重组小鼠白介素15(rm IL-15)、rm IL-2以及氢化可的松联合刺激体外扩增NK细胞。将扩增后Treg细胞及NK细胞按不同比例混合淋巴细胞培养,MTT比色法检测NK细胞的杀伤活性。将B16-F10小鼠黑色瘤细胞输注至Balb/c小鼠体内建立肺移植瘤模型[1],将荷瘤小鼠分为4组:A组单独接种B16-F10小鼠黑色瘤细胞;B组接种Treg细胞+B16-F10黑色素瘤细胞;C组接种B16-F10黑色素瘤细胞+NK细胞;D组接种Treg细胞+B16-F10黑色素瘤细胞+NK细胞。MTT比色法测定各实验组小鼠脾脏NK细胞的杀伤活性,并比较不同处理组小鼠肺部肿瘤结节数目。结果体外扩增后的Treg细胞对新鲜分选及扩增后的NK细胞活性均具有明显抑制作用(P0.05),且抑制作用呈剂量依赖关系;A组荷瘤小鼠NK细胞活性低于正常小鼠,且B组荷瘤小鼠NK细胞活性较A组进一步降低(P0.05);D组荷瘤小鼠NK细胞活性高于A组和B组荷瘤小鼠,但仍低于正常小鼠组(P0.05)。B组荷瘤小鼠肺部移植瘤数目(105.33±10.97)较A组明显增多(17±4.58)(P0.01);C组荷瘤小鼠肺部移植瘤数目(2.00±1.00)较A组(17±4.58)明显减少(P=0.037);D组荷瘤小鼠肺移植瘤数目(79.00±8.54)较B组明显降低(105.33±10.97)(P=0.030),但仍高于A组荷瘤小鼠(17±4.58)(P0.001)。结论体内种植肿瘤会抑制机体NK细胞活性;输注体外扩增Treg细胞能够通过抑制NK细胞发挥抗肿瘤免疫抑制;过继输注体外扩增NK细胞能够部分逆转Treg细胞介导的抗肿瘤免疫抑制。     

小鼠IL-1β在H22细胞的表达及对NK细胞杀伤活性的影响

目的：重组表达小鼠IL-1β全长基因，转染H22肝癌细胞，分析对NK细胞杀伤活性的影响。方法：构建小鼠IL-1β重组表达载体pIRES2-EGFP-mIL-1β，利用jetPEI转染H22肝癌细胞，RT—PCR和激光扫描共聚焦显微镜分析IL-1β重组载体的表达，MTT方法分析转染前后，野生型小鼠脾脏NK细胞对H22细胞杀伤活性的变化。结果：RT—PCR扩增出小鼠IL-1β，长度约843bp。纯化的PCR产物与pIRES2-EGFP同时经Xho I和EcoR I双酶切，在T4连接酶作用下连接，转化大肠杆菌，提取质粒经PCR、限制性酶谱分析（XhoI＋EcoRI）和DNA序列测定后，确认获得重组表达载体pIRES2-EGFP-mIL-1β。将该质粒转染至H22小鼠肝癌细胞中，RT—PCR和荧光观察证实，H22细胞能表达高水平IL-1β重组表达载体，与转染空载体的对照组细胞相比，IL-1β转基因后H22细胞对NK92细胞杀伤抵抗性明显增强，同时野生型小鼠脾脏NK细胞对pIRES2-EGFP-mIL-1β转基因细胞的杀伤活性明显下降，效靶比40：1时下降了约10％。结论：IL-1β能够明显增强H22肝癌细胞对NK细胞杀伤的抵抗性，可能是肝癌细胞借以逃逸天然免疫应答的重要机制。     

IL-2与眼镜蛇毒协同抗肿瘤作用的实验研究

本文研究了白细胞介素2(IL-2)和眼镜蛇毒对小鼠移植鼠肝癌的抑制作用以及对荷移植窟小鼠NK细胞杀伤活性的影响。结果表明:IL-2或眼镜蛇毒单独使用时,前者能明显增强荷瘤鼠的NK细胞活性,可是抑瘤作用不很明显;后者虽然严重地减弱荷瘤鼠的NK活性,但抑瘤作用反而较前者为强。当两者联合使用时,其抑瘤作用及NK活性则都显著提高(P<0.005)。提示IL-2与眼镜蛇毒具有良好的协同抗小鼠移植鼠肝癌的作用。     

MiR-191过表达抑制NK细胞的肿瘤杀伤活性和细胞凋亡

目的研究miR-191过表达对自然杀伤细胞(natural killer cell,NK)的凋亡和肿瘤杀伤活性的影响。方法通过免疫磁珠阴性分选方法从小鼠脾脏中分离NK细胞,体外用IL-2刺激扩增5～7 d后,采用流式细胞术分析NK细胞的细胞毒活性和凋亡情况。制备小鼠骨髓、脾脏、淋巴结和胸腺的单细胞悬液,计算细胞总数后,采用流式细胞术分析NK细胞的比例和数量。结果与野生型(WT)小鼠相比,miR-191过表达转基因TgmiR-191小鼠NK细胞的凋亡率及其对小鼠淋巴细胞瘤细胞RMA-S的特异性杀伤活性均显著降低。miR-191过表达可显著增加脾脏和淋巴结的NK细胞数量。结论 miR-191过表达对NK细胞的肿瘤杀伤活性和细胞凋亡有明显的抑制作用。     

小鼠IL-18基因修饰瘤苗的抗白血病作用研究

我们在前期工作中成功制备了IL-18基因修饰的白血病疫苗,为了探讨IL-18基因修饰瘤苗的体内抗白血病作用,实验采用L1210小鼠淋巴细胞白血病模型,在小鼠体内接种IL-18基因修饰瘤苗,观察瘤苗对L1210细胞致瘤性的影响及免疫保护作用,并进一步对其抗白血病作用机制进行了探索。结果显示,IL-18基因修饰瘤苗能够明显延长荷瘤小鼠存活时间,大部分小鼠达到长期生存,且长生存小鼠用野生型L1210细胞二次攻击后大多数仍能长期生存,表明IL-18基因修饰瘤苗有显著的抗白血病作用,并可诱导小鼠产生免疫记忆和免疫保护。机制探讨发现,接种IL-18基因修饰瘤苗后,小鼠脾脏淋巴细胞对L1210肿瘤细胞的CTL及NK细胞杀伤活性明显高于对照组(P<0.05),提示IL-18基因修饰瘤苗能够显著增强抗肿瘤CTL和NK细胞反应。接种瘤苗可使小鼠IFN-γ水平升高,但与对照相比无统计学意义,提示IFN-γ可能在IL-18基因修饰瘤苗诱导的抗肿瘤免疫应答中作用不大。     

黄芪多糖佐剂对脾脏NK细胞及NKT细胞的作用

目的观察脾脏NK细胞及NKT细胞在黄芪多糖（APS）发挥免疫佐剂功能的作用。方法使用鸡卵白蛋白（OVA）与APS经皮下免疫C57BL/6小鼠3次。末次免疫7～14d,取血清,使用ELISA观察OVA特异性抗体的含量;分离脾脏淋巴细胞,使用流式细胞仪检测NK和NKT细胞的百分比含量;使用PMA和Ionimycin刺激淋巴细胞,使用细胞内细胞因子染色的方法检测IFN-γ和IL-4的分泌情况。结果 APS组小鼠OVA特异性抗体含量明显高于OVA组小鼠（P〈0.05）,但小鼠脾脏内NK和NKT细胞的百分比含量与OVA组和正常小鼠差别不大（P〉0.05）。经PI刺激以后,APS组小鼠脾脏内NK细胞中IL-4＋细胞明显高于OVA组和正常组（P〈0.05）,且IFN-γ＋细胞的比例明显下降（P〈0.05）;虽然经过PI刺激以后,APS组小鼠脾脏内NKT细胞中IL-4＋细胞升高不明显,但是IFN-γ＋细胞的比例明显下降（P〈0.05）。结论 APS可以通过调节NK和NKT细胞的功能来促进体液免疫应答。     

PD-L1阻断改善酵母多糖致伤小鼠脾脏耐受性 DC对T淋巴细胞活性的影响

目的：探讨酵母多糖致伤小鼠脓毒症病程发展过程中脾脏耐受性树突状细胞( dendritic cell, DC)的形成对脾脏T淋巴细胞免疫活性的影响,并通过程序性死亡受体-1(programmed death-1,PD-L1)抗体阻断PD-L1/PD-1途径改善耐受性DC对T淋巴细胞活性的抑制作用。方法采用酵母多糖腹腔注射的方法复制小鼠脓毒症模型。用磁珠法分离致伤小鼠脾脏DC和T淋巴细胞,测定脾脏组织中DC上PD-1、PD-L1、PIR-B的表达水平和分泌IL-12、IL-10的能力;检测脾脏T淋巴细胞增殖活性和IL-2的分泌水平。进一步将致伤组小鼠脾脏DC与正常小鼠脾脏T淋巴细胞混合培养,并加入PD-L1抗体,检测T淋巴细胞增殖活性及混合培养上清中IL-2、IL-12和IL-10含量。结果酵母多糖致伤后5天和12天组小鼠脾脏DC上PD-1、PD-L1及PIR-B的表达大幅上调,IL-12p70分泌减少,IL-12p40和IL-10分泌增加;脾脏T淋巴细胞增殖活性降低、IL-2分泌减少。在致伤组DC与正常T淋巴细胞混合培养体系中加入PD-L1抗体可减轻致伤组DC对T淋巴细胞增殖活性和分泌IL-2的抑制作用,并改善DC上IL-12p70、IL-12p40和IL-10的分泌能力。结论酵母多糖诱导小鼠脓毒症的病程晚期,脾脏耐受性DC的形成导致T淋巴细胞活性降低;PD-L1抗体通过干预PD-1/PD-L1途径改善T淋巴细胞和DC的免疫活性。     

氩氦刀冻融的肺癌细胞联合IL-2刺激人外周血单个核细胞免疫功能

观察氩氦刀冻融的肺癌细胞联合IL-2对正常人外周血单个核细胞免疫功能的作用。分离正常人外周血单个核细胞,分别与氩氦冻融的肺癌细胞、IL-2和氩氦冻融的肺癌细胞联合IL-2混合培养,并设空白对照组。分别在第3、7、14天检测培养上清液中IL-12含量及NK细胞、CTL细胞的杀伤活性。结果表明,单用氩氦冻融的肺癌细胞可以轻度增加IL-12含量,但不能增加NK细胞、CTL细胞的杀伤活性;氩氦冻融的肺癌细胞联合IL-2后,可明显提高NK细胞和CTL的杀瘤活性。氩氦冻融的肺癌细胞联合IL-2对增强NK细胞和CTL活性具有协同作用,此种作用可能是通过刺激IL-12分泌增加实现的。     

IL—6基因转染的瘤苗体内诱导的抗肿瘤免疫功能与效果

经丝裂霉素C体外处理后,将IL-6基因转染的、高分泌的IL-6的B16黑色素瘤细胞制成瘤苗。结果发现,体内注射IL-6基因转染的瘤苗后,小鼠脾脏CTL活性、NK活性及IL-2诱导的LAK活性显著升高。经IL-6基因转染瘤苗体内治疗后,荷瘤小鼠的皮下肿瘤生长显著减慢、肺转移结节数显著降低、存活期显著延长,若同时合用低剂量IL-2,则上述治疗效果更好。可见IL-6基因转染的瘤苗能有效地通过诱导机体抗肿瘤免疫功能而发挥抗肿瘤作用,与低剂量IL-2合用后,IL-6基因转染的瘤苗的抗肿瘤效果更佳。     

Production of gamma interferon by natural killer cells from Toxoplasma gondii-infected SCID mice: regulation by interleukin-10, interleukin-12, and tumor necrosis factor alpha.

Previous studies of mice have implicated natural killer (NK) cells as mediators of protective activity against Toxoplasma gondii through their production of gamma interferon (IFN-gamma). In the present study, we have compared NK-cell activity in infected and uninfected SCID mice. Our data reveal that infection results in increased levels of IFN-gamma in serum and elevated NK-cell activity but that these NK cells were not cytotoxic for T. gondii-infected P815 cells. Treatment with anti-IFN-gamma antibody abrogated the increase in NK-cell activity and resulted in earlier mortality of infected mice. In vivo treatment with anti-asialo GM1 antiserum reduced NK cell activity and levels of IFN-gamma in serum but did not alter time to death. Spleen cells from infected mice produced higher levels of IFN-gamma than those from uninfected mice when stimulated in vitro with live T. gondii or parasite antigen preparations. Further analysis revealed that interleukin 10 (IL-10) inhibited, whereas tumor necrosis factor alpha (TNF-alpha) and IL-12 enhanced, IFN-gamma production by spleen cells from infected or uninfected mice. The combination of IL-12 and TNF-alpha induced higher levels of IFN-gamma from whole spleen cells of infected mice than from those of uninfected mice. Depletion of the adherent cell population from the spleen cells of infected mice led to a significant reduction in the levels of IFN-gamma produced after stimulation with IL-12 plus TNF-alpha. Similar results did not occur with cells from uninfected mice. These data indicate that other cytokines produced by the adherent cell population from infected mice may be involved in maximal production of IFN-gamma by NK cells stimulated with IL-12 and TNF-alpha. To assess the importance of endogenous IL-12, a polyclonal anti-IL-12 was administered to infected SCID mice. This treatment led to earlier mortality, indicating that endogenous IL-12 mediates resistance to T. gondii.     

Activated murine natural killer cells control growth of Mycobacterium lepraemurium in mouse macrophages; in vitro and in vivo evidence.

The role of natural killer cells (NK) in murine leprosy was investigated in vivo and in vitro. In a first set of experiments, it was found that IL-2 (interleukin-2) activated NK cells reduced Mycobacterium lepraemurium (MLM) growth in mouse C57BL/J peritoneal macrophages which had phagocytosed low numbers (MOI of 10 : 1) of MLM (P less than 0.0001 at day 20). There was no cytotoxicity exerted by the NK cells against the infected cells in these conditions. Conversely, macrophages heavily infected with MLM (multiplicity of infection of 1000 : 1) were found to be susceptible to lysis by activated NK cells in vitro. In vivo, progressing murine leprosy was associated with a sharp increase in splenic NK cell activity, which was abrogated by treatment with a monoclonal antibody against NK cells. Administration of this monoclonal antibody against NK cells enhanced C57BL6/J mouse susceptibility to mouse leprosy, as seen by a decrease in survival time of mice infected with 10(7) MLM i.v. (81 days vs 110 days, P less than 0.0005). Overall, these findings suggest that NK cells may play an important role in resistance to leprosy, either by reducing MLM growth in macrophages or by lysing heavily infected macrophages.     

瘤型麻风动物模型血浆Ig的变化及其对ll—2产生的动态观察

本文报道了瘤型麻风小鼠模型血浆IgG,IgM和IgA含量的动态变化,以及感染鼠的血浆体外对正常鼠脾细胞IL—2生成的影响的动态观察。结果表明,随着感染时间的延长,小鼠血浆中的三种Ig的含量依次递增。进一步的研究发现,随着Ig水平的升高,感染小鼠的血浆对正常小鼠脾细胞IL—2生成呈现明显的抑制作用。加有感染1月、3月和6月的小鼠血浆的正常鼠脾细胞IL—2生成均明显降低(P<0.01),其抑制率分别为26.2％、40.0％和75.8％。结合我们的观察与瘤型麻风独特的免疫偏离进行了讨论。     

Suppressor cells induced by influenza virus inhibit interleukin-2 production in mice.

PR8 virus depressed interleukin-2 (IL-2) and natural killer (NK) cell activity in BALB/c infected mice. IL-2 production was not dependent on (i) a decreased number of T cells or (ii) a primary defect in IL-1 production, but on a T-suppressor cell subpopulation. In fact, when T suppressor cells were removed from infected spleen cells, we observed normal levels of IL-2 activity.     

Studies on the role of interleukin-12 in acute murine toxoplasmosis.

Interleukin-12 (IL-12) is important in the regulation of resistance to Toxoplasma gondii in mice with severe combined immunodeficiency (SCID). The protective ability of IL-12 in SCID mice appears to be through its activity on natural killer (NK) cells to induce production of interferon-gamma (IFN-gamma). In this study we assessed the role of IL-12 in the acute stage of toxoplasmosis in immunocompetent mice. Administration of IL-12 to BALB/c mice infected with the virulent C56 strain of T. gondii remarkably delayed time to death. The protective activity of IL-12 was abrogated by administration of monoclonal antibodies to IFN-gamma or tumour necrosis factor-alpha (TNF-alpha), and by depletion of NK cells using an antisera against asialoGM1. Whereas BALB/c mice infected with the ME49 strain of T. gondii survived infection, administration of anti-IL-12 to infected mice resulted in 100% mortality accompanied by decreased serum levels of IFN-gamma. Furthermore, this treatment significantly reversed the suppression of spleen cell proliferation to concanavalin A (Con A), which is associated with the acute stage of infection, and resulted in decreased ex vivo production of IFN-gamma, IL-2, IL-4 and IL-10 in response to Con A. Our results indicate an important role for IL-12 in mediating resistance to T. gondii during acute infection in immunocompetent mice, that NK cells are required for this protective activity, and that IL-12 is involved in the immunosuppression which accompanies this infection.     

Suppression of interleukin-2 production by macrophages in genetically susceptible mice infected with Leishmania major.

Spleen cells from BALB/c mice infected with 2 X 10(7) L. major promastigotes and developing progressive disease produced significantly lower levels of interleukin-2 (IL-2) in response to concanavalin A stimulation than did spleen cells from uninfected mice. In contrast, spleen cells from sublethally irradiated and infected mice, which were able to contain lesion development, produced significantly higher levels of IL-2. The increase in IL-2 production closely paralleled lesion regression. Mice protectively immunized by four intravenous injections with lethally irradiated promastigotes also produced enhanced levels of IL-2, which were sustained after challenge infection. In contrast, spleen cells from BALB/c mice given four s.c. injections of irradiated promastigotes produced high levels of IL-2 before but not after infection. These mice eventually produced levels of IL-2 indistinguishable from those of unimmunized mice with progressive disease. There is thus an inverse relation between disease progression and the ability of spleen cells to produce IL-2. Spleen cells from mice with uncontrolled disease not only produced lower levels of IL-2 but also impaired IL-2 production by normal spleen cells. The ability to inhibit IL-2 was abrogated by passing the cells through a Sephadex G-10 column, removal of plastic adherent cells, and removal of carbonyl iron-ingesting cells. Furthermore, Sephadex G-10 column-treated and plastic adherent, nonspecific esterase-positive spleen cells from mice with progressive disease were able to suppress IL-2 production by normal splenic T cells. The suppressive activity of the adherent cells was not affected by treatment with anti-Thy-1.2 antibody and complement. In contrast, adherent spleen cells from uninfected mice were devoid of such suppressor activity. The depressed IL-2 production by spleen cells from progressively infected mice could be restored to that of normal spleen cells by the addition of indomethacin to the culture. There was however, no correlation between IL-2 production and IL-1 activity in infected or immunized BALB/c mice. Thus, it appears that the suppression of IL-2 production is mediated by prostaglandins elaborated by macrophages from chronically infected mice.     

Interleukin-12 stimulation of lymphoproliferative responses in Trypanosoma cruzi infection.

The cytokine interleukin-12 (IL-12) is essential for resistance to Trypanosoma cruzi infection because it stimulates the synthesis of interferon-gamma (IFN-gamma), a major activator of the parasiticidal effect of macrophages. A less studied property of IL-12 is its ability to amplify the proliferation of T or natural killer (NK) lymphocytes. We investigated the role of endogenously produced IL-12 in the maintenance of parasite antigen (T-Ag)-specific lymphoproliferative responses during the acute phase of T. cruzi infection. We also studied whether treatment with recombinant IL-12 (rIL-12) would stimulate T-Ag-specific or concanavalin A (Con A)-stimulated lymphoproliferation and abrogate the suppression that is characteristic of the acute phase of infection. Production of IL-12 by spleen-cell cultures during T. cruzi infection increased in the first days of infection (days 3-5) and decreased as infection progressed beyond day 7. The growth-promoting activity of endogenous IL-12 on T-Ag-specific proliferation was observed on day 5 of infection. Treatment of cultures with rIL-12 promoted a significant increase in Con A-stimulated proliferation by spleen cells from normal or infected mice. Enhanced T-Ag-specific proliferation by rIL-12 was seen in spleen cell cultures from infected mice providing that nitric oxide production was inhibited by treatment with the competitive inhibitor NG-monomethyl-L-arginine (NMMA). Enhancement of proliferation promoted by IL-12 occurred in the presence of neutralizing anti-interleukin-2 (IL-2) antibody, suggesting that this activity of IL-12 was partly independent of endogenous IL-2. Thymidine incorporation levels achieved with rIL-12 treatment of the cultures were approximately 50% of those stimulated by rIL-2 in the same cultures.     

穿孔素介导的细胞凋亡机制在抗流感病毒感染免疫防御中作用的研究

目的：穿孔素介导的细胞凋亡机制在流感病毒初次感染中作用的研究。方法：用流感病毒A／PR／8／34经鼻感染穿孔素基因敲除鼠和同源对照C57BL／6小鼠，采用PFU方法测定肺内流感病毒增殖状况；免疫组织化学染色方法观察小鼠病毒感染后感染细胞的凋亡情况；利用乳酸脱氢酶释放法检测感染鼠脾淋巴细胞NK活性及CTL杀伤活性。结果：穿孔素基因缺乏导致流感病毒在小鼠肺内大量增殖；小鼠清除感染病毒所需时间延长；病毒感染细胞发生凋亡的时间亦因穿孔素的缺乏而延迟；感染小鼠脾淋巴细胞NK活性及CTL杀伤活性均显著降低。结论：穿孔素依赖的细胞介导的细胞毒效应在控制流感病毒初次感染，快速清除感染病毒方面起重要作用。