白介素10可保持蜕膜NKG2D+TGF-β-NK细胞低水平并有利于妊娠成功

为探讨白介素10(IL-10)及其受体IL-10R相互作用并调节妊娠耐受的可能机制.在孕E4.5、E6.5和E8.5给BALB/c×C57BL/6孕鼠腹腔注射抗IL-10R抗体.而给NOD×C57BL/6孕鼠腹腔注射莺组小鼠IL-10.在E10.5检测小鼠蜕膜NKG2D+TGF-β-NK细胞构成比和胚胎吸收率.研究发现...     

蜕膜NKT细胞过度表达穿孔素与流产发病的关系

采用腹腔注射α-半乳糖基神经酰胺(α-galactosylceramide,α-GC)的方法诱发C57BL/6小鼠流产,并检测注射后小鼠蜕膜NKT细胞表达穿孔素的情况,进而分析α-GC导致流产的发病机制。研究发现,在孕6.5 d腹腔注射α-GC(100μg/kg体重)可使小鼠孕10.5 d胚胎吸收率达到35.6%(37/104),显著高于对照组(7.4%;10/135;P<0.01)。此时采用流式细胞术检测蜕膜CD3+CD49b+NK1.1+细胞表达穿孔素的水平,发现α-GC刺激后穿孔素平均检出率显著高于对照组(15.5%和4.6%;P<0.01)。预先注射穿孔素的选择性抑制剂乙二醇四乙酸(ethylene glycol tetraacetic acid,EGTA)抑制穿孔素的作用,可显著降低α-GC所引起的小鼠胚胎吸收率增高。EGTA处理组和溶剂对照组α-GC诱导后小鼠胚胎吸收率分别为13.4%(16/119)和40.8%(42/103;P<0.01)。这些结果提示,α-GC可上调NKT细胞穿孔素的表达,而过多的穿孔素可能是α-GC导致小鼠胚胎吸收率增高的分子基础。     

双链RNA和咪喹莫特联合刺激的协同作用研究

目的 研究双链RNA(double-stranded RNA,dsRNA)和咪喹莫特联合刺激是否具有协同效应.方法 在Toll样受体3(TLR3)的特异性刺激剂dsRNA、TLR7的特异性刺激剂咪唪莫特(R837)单独刺激或二者联合刺激条件下,检测BALB/c×C57BL/6和NH细胞缺陷的非肥胖型糖尿病(NOD)×C57BL/6小鼠胚胎吸收率.采用小鼠体内注射上述刺激剂的方法 ,流式细胞术检测子宫CD45+细胞内细胞因子表达水平.为进一步鉴定CD45+细胞身份,在体外培养系统中采用dsRNA和咪喹莫特刺激胎盘和底蜕膜来源的子官CD3+T细胞和CD49b+NK细胞,并检测细胞内细胞因子表达水平.采用丝裂原激活的蛋白激酶(mitogen-activated protein kinase,MAPK)抑制剂SP600125和PD98059阻断细胞因子表达水平的增加.结果 此 dsRNA和咪喹莫特联合刺激对胚胎吸收率的增高具有协同作用,同时对CD45+细胞内TNF-α和IFN-γ的表达增强具有协同刺激作用.进一步细胞鉴定研究显示,虽然在BALB/c小鼠CD3+细胞和CD49b+NK细胞中均可发现这种协同效应,但是在NOD小鼠,这种细胞因子水平的增高应主要归因于CD3+T细胞,因为在CD49b+NK细胞不显示这种细胞因子增高趋势.上述刺激剂合用的协同效应町部分地被JNK(Jun N-terminal kinase)MAPK抑制剂SP600125阻断,而几乎被ERK(extracellular signal.regulated kinase)MAPK抑制剂PD98059所完全阻断.结论 增强的TLR3和TLR7联合信号可能是通过NOD小鼠Th1型T细胞,而不是NK细胞所传导.ERK MAPK途径可能在TLR3和TLR7参与的细胞信息传递过程中发挥关键性作用.     

通过TLR9途径活化巨噬细胞导致小鼠流产的机制研究

为研究低甲基化型CpG与TLR9相互作用激活巨噬细胞并诱发小鼠妊娠失败的机制,本研究模拟特异性配体CpG活化TLR9的过程,并比较CpG对NK1.1+CD3-细胞和CD11b+F4/80+细胞数量、TNF-α表达水平以及妊娠结局的影响。研究发现,在孕6.5d腹腔注射CpG可显著提高非肥胖型糖尿病(non-obese diabetic,NOD)小鼠胚胎吸收率。相反,相同剂量对野生型BALB/c小鼠则无此影响。胚胎吸收率的增高伴有CD11b+F4/80+巨噬细胞相对数量增多和血清TNF-α水平增高,但是NK细胞构成比无显著改变。采用F4/80中和抗体抑制CD11b+F4/80+巨噬细胞可显著降低血清TNF-α水平,并降低胚胎吸收率。这些证据表明,CpG通过激活TLR9,并提高蜕膜CD11b+F4/80+巨噬细胞相对数量、增强TNF-α表达,进而导致胚胎吸收率增高。     

脂多糖诱发的同基因妊娠BALB/c和NOD/SCID小鼠早产模型

目的：研究脂多糖（LPS）诱发同基因妊娠BALB/c小鼠和非肥胖性糖尿病/重度联合免疫缺陷（NOD/SCID）小鼠早产的机制。方法：在预先阻断或未阻断Toll样受体4（TLR4）的条件下采用LPS刺激,并比较各组BALB/c和NOD/SCID小鼠的早产率和胚胎死亡率。由于预实验显示预期的早产均发生于孕16d,因此,实验中在早产发生之前处死小鼠,收集每只孕鼠的胎盘。采用流式细胞术检测胎盘CD45^＋细胞表面TLR4、CD80和细胞内TNF-α的表达率。结果：采用LPS可诱发BALB/c小鼠早产,而NOD/SCID小鼠则对LPS的诱导有抵抗。经LPS刺激后,TLR4的表达在BALB/c和NOD/SCID小鼠均无显著改变,但是两组小鼠CD45^＋CD80^＋细胞的百分率均升高。相反,LPS刺激后仅BALB/c小鼠CD45＋TNF-α＋细胞的百分率升高,而NOD/SCID小鼠则否。通过预先阻断TLR4的表达可消除LPS对BALB/c小鼠CD80和TNF-α表达的影响,并显著降低LPS诱发的早产率。结论：虽然LPS未能改变TLR4的表达,但是二者相互作用,可激发CD45^＋CD80^＋细胞的动员,导致炎性细胞因子产生增多,并最终导致早产。BALB/c和NOD/SCID小鼠对LPS刺激的敏感性存在差异,提示NOD/SCID小鼠缺乏功能正常的T细胞和NK细胞,可能是这种小鼠对LPS诱发的早产有抵抗的原因之一。     

TLR3参与poly(I-C)所致流产的作用

目的研究Toll样受体3(toll-like receptor 3,TLR3)在poly(I-C)诱发小鼠流产中的潜在作用。方法多聚次黄苷酸-胞苷酸[polyinosinic-polycytidync acid,poly(I-C)]是一种双链RNA,腹腔注射时能够诱发小鼠流产。在预先用单抗阻断或不阻断TLR3情况下,注射poly(I-C)建立小鼠诱发性流产模型,应用流式细胞术分别检测CD45+DX5+和DX5+CD69+细胞百分率。结果不用抗TLR3抗体预处理,单用poly(I-C)刺激同种异基因交配模型BALB/c×C57BL/6,可使CD45+DX5+和DX5+CD69+细胞百分率均显著升高。但是,应用抗TLR3抗体预处理的雌鼠,用poly(I-C)刺激时上述百分率不改变。与此相应,poly(I—C)刺激可显著增高胚胎吸收率,而抗TLR3抗体预处理可消除这种作用。结论poly(I-C)与TLR3结合可能对母-胎界面NK细胞活化至关重要,并可促进小鼠胚胎吸收。     

LPS对MRL/MpJ小鼠脾T细胞表达TLR4和TNFα的影响

研究Toll样受体 4 (TLR4 )在MRL/MpJ小鼠脾细胞的表达状况和革兰阴性菌脂多糖 (LPS )刺激后TLR4的表达变化以及对TNF α产生的影响。MRL/MpJ小鼠经腹腔注射LPS后在不同时间取脾细胞 ,用三色荧光标记流式细胞仪技术检测小鼠脾T细胞TLR4的表达情况 ,并与BALB/c小鼠作对照 ;通过RT PCR观察LPS刺激前后脾T细胞TNF αmRNA的表达变化。结果表明TLR4在MRL/MpJ小鼠CD3+ CD4 + T细胞和CD3+ CD8+ T细胞中均有表达 ;但TLR4 + /CD4 + 细胞表达仅BALB/c小鼠的 33% ,在受LPS刺激后 ,MRL/MpJ鼠CD4 + T细胞TLR4升高时间较BALB/c小鼠延迟 ;CD8+ T细胞TLR4在LPS刺激前后无明显变化 ;脾细胞TNF αmRNA水平升高亦延迟。通过对干燥综合征样自身免疫病鼠模型MRL/MpJ小鼠脾T细胞TLR4的表达及功能研究 ,将有助于认识天然免疫和获得性免疫间的联系和感染在自身免疫病发病中的作用。     

日本血吸虫感染的小鼠肠系膜淋巴结γδT细胞、NK细胞和NKT细胞表型的变化

日本血吸虫病是由血吸虫引起的一种慢性寄生虫病。本研究着力于探究日本血吸虫(Schistosome japonicum,S.j.)感染的C57BL/6小鼠肠系膜淋巴结不同固有免疫细胞的表型变化。C57BL/6小鼠感染日本血吸虫6周,分离肠系膜淋巴结,制备单细胞悬液,检测固有免疫细胞及其表面相关分子的表达情况。结果显示肠系膜淋巴结中γδT细胞、NK细胞和NKT细胞数量明显增多(P<0.05),但只有NK细胞的百分比含量明显增加(P<0.05);γδT细胞、NK细胞和NKT细胞表面CD69表达显著增高(P<0.01),而CD25的变化均不明显(P>0.05);γδT细胞和NK细胞表面CD4增高(P<0.05);NK细胞表面NKG2A/C/E(CD94)、NKG2D(CD314)表达及NKT细胞表面NKG2D(CD314)表达降低(P<0.05)。表明日本血吸虫感染C57BL/6小鼠肠系膜淋巴结不同固有免疫细胞的表型变化存在显著差异。     

小鼠流产模型子宫NK细胞CD25和Foxp3表达特征

探讨CD25和Foxp3分子表达水平与自发性流产小鼠模型流产发病机制的关系。采用磁珠亲和细胞分选术分离小鼠子宫NK细胞,并采用流式细胞术检测NK细胞表达CD25和Foxp3分子的情况,比较自发性流产小鼠CBA/J×DBA/2J和正常对照CBA/J×BALB/c小鼠流产率和上述分子表达水平的差异。在孕早期给CBA/J×DBA/2J雌鼠过继输注CD49~+CD25~+Foxp3~+NK细胞,观察其胚胎丢失率的变化。结果显示,CBA/J×DBA/2J小鼠孕12.5 d胚胎吸收率显著高于CBA/J×BALB/c对照组(分别为23.4%和5.5%,P0.01),而CBA/J×DBA/2J小鼠孕12.5 d子宫NK细胞CD25和Foxp3阳性率均显著低于CBA/J×BALB/c小鼠(CD25阳性率分别是4.8%和10.5%,Foxp3阳性率分别是0.3%和7.4%,均为P0.01)。进一步检测发现,这些细胞不表达CD3和CD4分子。此外,输注CD49~+CD25~+Foxp3~+NK细胞可显著降低CBA/J×DBA/2J小鼠孕12.5 d胚胎吸收率(治疗组与对照组分别为8.0%和24.7%,P0.01)。这些结果提示,CBA/J×DBA/2J小鼠自发性胚胎吸收率增高可能与子宫NK细胞缺乏CD25和Foxp3分子的足量表达有关。     

异基因MHC Ⅰ修饰对骨髓细胞的免疫学特性的影响

目的：观察异基因MHC Ⅰ修饰对骨镑细胞的免疫学特性的影响，探讨MHC Ⅰ类分子在诱导免疫耐受中的作用机制。方法：由逆转录病毒载体pMSCV介导，将BALB/C小鼠的MHC Ⅰ类分子H—2D^d基因导入C57BL/6小鼠的骨骼细胞，流式细胞仪检测转染后基因的表达。MTT法检测混合淋巴细胞反应，乳酸脱氢酶释放法测定BALB/C小鼠NK细胞对H-2D^d修饰后C57BL/6小鼠骨髓细胞的杀伤活性。结果：重组逆转录病毒感染的C57BL/6小鼠骨髓细胞对BALB/C小鼠脾细胞的刺激强度或应答程度，与未转染和空载体病毒感染的C57BL/6小鼠骨髓细胞相比都显著减弱。BALB/C小鼠NK细胞对转染H-2D^d基因后的C57BL/6小鼠骨髓细胞的杀伤显著降低。结论：在骨髓移植中用受者MHC Ⅰ分子修饰供者骨髓细胞可能诱导免疫耐受。     

妊娠子宫微环境中uNK细胞NKG2A和NKG2D及其配体表达的研究

目的：研究妊娠子宫微环境中子宫自然杀伤细胞（uNK细胞）NKG2A和NKG2D及其相应配体的表达，探讨NKG2A与NKG2D的不平衡表达在母胎免疫耐受形成中的作用。方法：选择30例孕6-9周的正常妊娠妇女,分离其新鲜蜕膜组织，除去绒毛,分离蜕膜和外周血单个核细胞，采用流式细胞仪测定NK细胞的数量及NKG2A与NKG2D的表达；采用RT-PCR技术检测滋养层组织NKG2A与NKG2D配体人类白细胞抗原-E(HLA-E)、主要组织相容性复合体-Ⅰ类分子相关蛋白A(MICA)mRNA的表达结果：妊娠子宫蜕膜淋巴细胞中NK细胞约占70%,流式细胞分析的结果显示，子宫自然杀伤细胞NKG2A的表达显著高于外周血NK细胞，分别为97.86%±1.75%与33.35%±10.92%（〖AKx-D〗±s），两者差异显著（P<0.05），在滋养层细胞中检测到其配体HLA-E的表达；而与外周血相比，uNK细胞表面NKG2D的表达与之较为相近，分别为93.21%±4.52%与97.80%±1.72%，但两者仍有显著差异（P<0.05）。在滋养层组织未检测到其相应配体MICA mRNA的表达结论：蜕膜中的淋巴细胞主要为NK细胞，其免疫学表型与外周血NK细胞有较大的区别，妊娠期子宫自然杀伤细胞表面高表达抑制性受体NKG2A，同时滋养层组织表达相应的配体人类白细胞抗原-E，这可能是维持母胎界面免疫耐受的重要因素。     

ICAM-1参与脂多糖刺激引起蜕膜细胞应激状态的机制研究

为探讨细胞间粘附分子-1(ICAM-1)参与脂多糖(LPS)刺激引起蜕膜细胞应激状态的机制,本研究采用LPS刺激和联合阻断ICAM-1及其受体LFA-1(CD11a/CD18,α1β1整合素)的策略,观察小鼠蜕膜LFA-1+细胞和调节性T细胞相对数量的改变,并检测胚胎吸收率的相应变化。LPS刺激可使小鼠胚胎丢失率显著增高,而采用中和抗体抑制ICAM-1/LFA-1通路则可基本消除这一效应。进一步研究发现,LPS可使小鼠蜕膜LFA-1+细胞相对数量显著增多,调节性T细胞相对数量显著减少。相反,抑制ICAM-1/LFA-1可消除上述LPS所造成的影响。结果提示,LPS刺激可激活ICAM-1/LFA-1信息通路,减少蜕膜Treg细胞的相对数量,并导致小鼠母-胎间免疫耐受失衡而发生流产。     

Expression and function of NKG2D in CD4+ T cells specific for human cytomegalovirus

The human NKG2D killer lectin-like receptor (KLR) is coupled by the DAP10 adapter to phosphoinositide 3-kinase (PI3 K) and specifically interacts with different stress-inducible molecules (i.e. MICA, MICB, ULBP) displayed by some tumour and virus-infected cells. This KLR is commonly expressed by human NK cells as well as TCRgammadelta(+) and TCRalphabeta(+)CD8(+) T lymphocytes, but it has been also detected in CD4(+) T cells from rheumatoid arthritis and cancer patients. In the present study, we analysed NKG2D expression in human cytomegalovirus (HCMV)-specific CD4(+) T lymphocytes. In vitro stimulation of peripheral blood mononuclear cells (PBMC) from healthy seropositive individuals with HCMV promoted variable expansion of CD4(+)NKG2D(+) T lymphocytes that coexpressed perforin. NKG2D was detected in CD28(-) and CD28(dull )subsets and was not systematically associated with the expression of other NK cell receptors (i.e. KIR, CD94/NKG2 and ILT2). Engagement of NKG2D with specific mAb synergized with TCR-dependent activation of CD4(+) T cells, triggering proliferation and cytokine production (i.e. IFN-gamma and TNF-alpha). Altogether, the data support the notion that NKG2D functions as a prototypic costimulatory receptor in a subset of HCMV-specific CD4(+) T lymphocytes and thus may have a role in the response against infected HLA class II(+) cells displaying NKG2D ligands.     

HLA-E is expressed on trophoblast and interacts with CD94/NKG2 receptors on decidual NK cells

Non-classical MHC class I molecule HLA-E is the ligand for CD94/NKG2 NK cell receptors. Surface expression of HLA-E requires binding of specific HLA class I leader sequences. The uterine mucosa in early pregnancy (decidua) is infiltrated by large numbers of NK cells, which are closely associated with placental trophoblast cells. In this study we demonstrate that trophoblast cells express HLA-E on their cell surface in addition to the previously reported expression of HLA-G and HLA-C. Furthermore, we show that the vast majority of decidual NK cells bind to HLA-E tetrameric complexes and this binding is inhibited by mAb to CD94. Thus, recognition of fetal HLA-E by decidual NK cells may play a key role in regulation of placentation. The functional consequences of decidual NK cell interaction were investigated in cytotoxicity assays using polyclonal decidual NK cells. The overall effect of CD94/NKG2 interaction with HLA-E is inhibition of cytotoxicity by decidual NK cells. However, since decidual NK cells are unable to kill trophoblast even in the presence of mAb to MHC class I molecules and NK cell receptors, HLA-E interaction with CD94/NKG2 receptors may regulate other functions besides cytolysis during implantation.     

不明原因自然流产与蜕膜NK细胞表面活化性受体表达的相关性研究

探讨不明原因自然流产患者蜕膜NK细胞杀伤活性与其细胞表面活化性受体NKp46、NKp44、NKp30和NKG2D表达的相关性。选取21例早孕不明原因自然流产患者为病例组,25例正常早孕人流妇女为对照组,收集两组的蜕膜组织,Ficoll密度梯度离心分离淋巴细胞,MACS磁珠分选CD3-CD56+NK细胞。以K562细胞为靶细胞,用细胞染色及流式细胞技术检测两组蜕膜NK细胞杀伤活性,用流式细胞技术检测两组蜕膜CD56brightCD16-NK和CD56dimCD16+NK细胞上活化性受体NKp46、NKp44、NKp30和NKG2D的表达,并与NK细胞杀伤活性进行相关性分析。结果:(1)早孕蜕膜NK细胞具有杀伤活性;(2)病例组蜕膜NK细胞的杀伤活性较正常对照组显著增强(P=0.014);(3)病例组蜕膜CD56brightCD16-NK细胞中NKp44的表达比正常对照组显著升高(P=0.021);病例组蜕膜CD56dimCD16+NK细胞中NKp46和NKp44的表达比正常对照组显著升高(分别P=0.026,P=0.041);其余活化性受体的表达两组未见明显差异;(4)蜕膜NK细胞杀伤功能与蜕膜CD56brightCD16-NK细胞中NKp44的表达呈显著正相关(r=0.677,P<0.05),和蜕膜CD56dimCD16+NK细胞中NKp46的表达呈显著正相关(r=0.634,P<0.05)。蜕膜NK细胞活化性受体NKp46和NKp44表达增加,从而使蜕膜NK细胞的杀伤功能增强可能在不明原因自然流产的发病中起重要作用。     

Requirements for control of B‐cell lymphoma by NK cells

The role of NK cells in the control of endogenously arising tumors is still unclear. We monitored activation and effector functions of NK cells in a c‐myc‐transgenic mouse model of spontaneously arising lymphoma. At early stages, tumors demonstrated reduced MHC class I expression and increased expression of natural killer group 2D ligands (NKG2D‐L). NK cells in these tumors showed an activated phenotype that correlated with the loss of tumor MHC class I. With increasing tumor load however, NK‐cell effector functions became progressively paralyzed or exhausted. In later stages of disease, tumors re‐expressed MHC class I and lost NKG2D‐L, suggesting a role of these two signals for NK cell‐mediated tumor control. Testing a panel of lymphoma cell lines expressing various MHC class I and NKG2D‐L levels suggested that NK cell‐dependent tumor control required a priming and a triggering signal that were provided by MHC class I down‐regulation and by NKG2D‐L, respectively. Deleting either of the “two signals” resulted in tumor escape. At early disease stages, immune stimulation through TLR‐ligands in vivo efficiently delayed lymphoma growth in a strictly NK cell‐dependent manner. Thus, NK‐receptor coengagement is crucial for NK‐cell functions in vivo and especially for NK cell‐mediated tumor surveillance.     

NK cell‐extrinsic IL‐18 signaling is required for efficient NK‐cell activation by vaccinia virus

NK cells are important for the control of vaccinia virus (VV) in vivo. Recent studies have shown that multiple pathways are required for effective activation of NK cells. These include both TLR‐dependent and ‐independent pathways, as well as the NKG2D activating receptor that recognizes host stress‐induced NKG2D ligands. However, it remains largely unknown what controls the upregulation of NKG2D ligands in response to VV infection. In this study using C57BL/6 mice, we first showed that IL‐18 is critical for NK‐cell activation and viral clearance. We then demonstrated that IL‐18 signaling on both NK cells and DCs is required for efficient NK‐cell activation upon VV infection in vitro. We further showed in vivo that efficient NK‐cell activation in response to VV is dependent on DCs and IL‐18 signaling in non‐NK cells, suggesting an essential role for NK cell‐extrinsic IL‐18 signaling in NK‐cell activation. Mechanistically, IL‐18 signaling in DCs promotes expression of Rae‐1, an NKG2D ligand. Collectively, our data reveal a previously unrecognized role for NK cell‐extrinsic IL‐18 signaling in NK‐cell activation through upregulation of NKG2D ligands. These observations may provide insights into the design of effective NK‐cell‐based therapies for viral infections and cancer.     

体外LPS刺激及CD40的配基化对sCD40基因修饰DCs TLR4-MD2表达及IL-12分泌的影响

目的： 研究体外LPS刺激及CD40的配基化对可溶性CD40（sCD40）基因修饰树突状细胞TLR4-MD2表达及IL-12分泌的影响,为有效利用树突状细胞诱导特异性移植免疫耐受提供实验依据。方法: 脂质体法将质粒pEGFP-N1/sCD40及空质粒pEGFP-N1转染DC2.4细胞株;应用LPS及抗CD40单抗刺激6 h,流式细胞仪检测DC表面TLR4-MD2的表达,RT-PCR法检测DC 的TLR4 mRNA 表达水平,并用ELISA法检测细胞因子IL-12p70的分泌。结果: LPS刺激下调DC表面TLR4-MD2的表达,同时给予CD40配基化可引起TLR4-MD2的表达显著增高;CD40配基化对DC TLR4mRNA 水平表达无影响，但可部分地增高LPS引起的TLR4mRNA 表达降低;此外,CD40的配基化可显著诱导LPS刺激后IL-12分泌增加。sCD40基因修饰DC可拮抗以上作用。结论: 体外LPS及抗CD40单抗刺激下,sCD40基因修饰树突状细胞可显著下调其表面TLR4-MD2的表达,IL-12p70分泌减少，可能与阻断胞浆内的TLR4-MD2的转运过程有关。