含HIV-1核心蛋白基因的重组质粒的构建及其免疫应答的研究

目的构建含有HIV-1核心蛋白gag基因的真核表达质粒,并研究其免疫应答反应。方法采用PCR方法从1例HIV感染者中扩增出gag基因,构建重组质粒pcDNA-GAG。接种小鼠后,检测其抗体及抗体亚类,并对小鼠的淋巴细胞亚群进行分析,采用3H-TdR法、ELISPOT方法和51Cr释放法分别检测T淋巴细胞的增殖反应性、特异性分泌IFN-γ的CD8+T淋巴细胞以及特异性CTL杀伤活性。结果重组质粒体外表达目的蛋白的相对分子质量(Mr)约为55×103。免疫小鼠后可诱导产生特异性抗体,其中IgG2a与IgG的比例显著高于IgG1与IgG的比例;T淋巴细胞体外经ConA刺激后SI达到160.67,显著高于对照组(14.04,P<0.05);产生IFN-γ的CD8+T淋巴细胞数目以及特异杀伤率均显著高于对照组小鼠(P<0.05)。结论重组质粒pcDNA-GAG可诱导小鼠产生特异性体液和细胞免疫应答反应,而且ELISPOT方法检测特异性细胞免疫应答反应的结果与51Cr释放法一致,提示可用此法对DNA疫苗诱导的细胞免疫进行评价。     

EB病毒和ConA诱导抑制性T细胞对EB病毒感染B细胞作用探讨

本文探讨了用灭活的EB病毒(EBV)和ConA诱导产生的抑制性T细胞(Ts),对EBV感染自身B细胞的影响,结果表明,EBV抗原诱导产生的抑制性T细胞(Ts)能使EBV感染B细胞中的EBNA阳性细胞数,~3H-TdR掺入量和IgA、IgG及IgM分泌量减少;而ConA诱导产生的Ts则使EBNA阳性细胞数和~3H-TdR掺入量增加,但三种Ig含量无明显变化(P>0.05)。结果提示前者对EBV感染B细胞的激活,增殖和分化均有明显抑制作用,而后者的作用则相反,具有明显促进EBV感染B细胞的作用。     

白术多糖对小鼠淋巴细胞的免疫调节作用

目的:探讨白术多糖对小鼠脾淋巴细胞的免疫调节作用。方法:将白术多糖和ConA或LPS及小鼠脾淋巴细胞在体外共培养,MTT法检测淋巴细胞转化;ELISA法检测细胞培养上清中细胞因子(IL-2、IL-6、IL-10和TNF-α)和IgG含量;RT-qPCR法检测白术多糖联合ConA或LPS对转录因子T-bet、Gata3和NF-κB mRNA表达的影响;流式细胞术检测白术多糖联合LPS对CD3、CD4、CD8和CD19淋巴细胞亚群比例的影响。结果:白术多糖促进ConA诱导的脾脏T淋巴细胞转化、IL-2、IL-6、IL-10和TNF-α分泌和转录因子(T-bet和Gata3)mRNA表达,抑制LPS对脾脏B淋巴细胞的激活,减少TNF-α和IgG分泌,降低NF-κB mRNA表达水平,降低LPS诱导的CD3、CD4和CD8淋巴细胞亚群比例。结论:白术多糖可促进ConA诱导的淋巴细胞转化,但抑制LPS诱导的淋巴细胞转化。     

连翘提取物对小鼠T淋巴细胞体外活化与增殖的影响

目的:分析连翘(FS)提取物对小鼠淋巴结T细胞的体外活化与增殖的影响,初步探讨其免疫抑制作用机制.方法:无菌分离小鼠淋巴结细胞,加入多克隆刺激剂刀豆蛋白A(ConA)进行刺激,利用荧光标记的单克隆抗体(mAb)染色结合流式细胞术(FCM),检测小鼠T淋巴细胞的表达的活化抗原CD69、CD25、CD71的表达情况;以羧基荧光素乙酰乙酸琥珀酰亚胺酯(CFDA-SE)染色,以FCM分析FS对淋巴细胞体外增殖的影响.结果:终浓度为40、80、160 mg/L的FS均对ConA刺激诱导的T细胞CD69、CD25和CD71的表达有降低作用(P＜0.05).CFDA-SE染色分析显示,上述浓度的FS对ConA诱导的小鼠T淋巴细胞增殖具有抑制作用(P＜0.05).结论:FS对ConA诱导的T细胞早、中、后期活化和体外增殖有抑制作用.     

橙皮素对小鼠T淋巴细胞体外活化与增殖的影响

目的:研究橙皮素(Hes)对小鼠T细胞体外活化和增殖的影响,并探讨其作用机制.方法:用ConA刺激小鼠淋巴结来源的淋巴细胞,以不同终浓度Hes与T细胞共培养,利用荧光标记抗体双染色结合流式细胞术(FCM),检测各药物浓度Hes对ConA诱导的小鼠T细胞表达早期活化抗原CD69的作用;以酶标仪结合MTT比色法检测Hes药物的细胞毒性和对ConA诱导的小鼠淋巴结来源的淋巴细胞增殖的影响;以羧基荧光素乙酰乙酸(CFDA-SE)染色结合FCM检测Hes对ConA诱导的小鼠T细胞增殖的作用,并应用ModFit软件分析其增殖指数(PI).结果:淋巴细胞的存活率说明0.2 mL/L DMSO和25～75 μmol/L范围内的Hes对小鼠T淋巴细胞无毒副作用;MTT法、CFDA-SE法、双抗体染色法检测Hes对ConA诱导的小鼠T淋巴细胞的增殖和活化结果均显示,终浓度为25、50、75 μmol/L的Hes对ConA诱导的小鼠T淋巴细胞的增殖和活化均有抑制作用且呈剂量依赖关系.结论:有望通过进一步的研究将Hes发展为免疫抑制药物.     

间充质干细胞体外对ITP患者T淋巴细胞分泌功能的影响

目的： 体外观察间充质干细胞（MSCs）对特发性血小板减少性紫癜（ITP）患者T淋巴细胞分泌细胞因子功能的影响。方法: 采用Ficoll分离和体外贴壁、传代培养,扩增出骨髓MSCs;通过Ficoll分离法和尼龙棉柱法获取ITP患者外周血T淋巴细胞。以经丝裂霉素（MMC）处理后不同数量（2×103、1×104、5×104 cells/well）的MSCs作为基底层细胞,接种体外分离纯化的异体ITP患者T淋巴细胞,分别于2 d、4 d、6 d后各自收集培养上清,用酶联免疫吸附试验(ELISA)法动态测定T淋巴细胞分泌白细胞介素2(IL-2)、干扰素-γ(IFN-γ)、白细胞介素4(IL-4)、白细胞介素10(IL-10)水平的变化。结果: ITP患者T淋巴细胞分泌细胞因子IL-2、IFN-γ较正常人高(P<0.05),IL-4、IL-10较正常人低(P<0.05)。MSCs可显著抑制ITP患者或正常对照组T淋巴细胞分泌IL-2、IFN-γ(P<0.05),且随MSCs数量的增加,抑制增强(P<0.05),共培养4 d、6 d时作用明显强于2 d时(P<0.05);MSCs可促进ITP患者T淋巴细胞分泌IL-4、IL-10 (P<0.05),且随MSCs量的增加,促进作用增强(P<0.05),对IL-10的作用随时间延长而增强(P<0.05),但对IL-4的作用在培养第2 d、4 d、6 d时无显著差异(P>0.05);在正常对照组,当MSCs数量>1×104可以促进T淋巴细胞分泌IL-4 与IL-10 (P<0.05),且随MSCs数量的增加,作用增强(P<0.05),共培养4 d、6 d时作用明显强于2 d时(P<0.05)。结论: MSCs能够在体外调节ITP患者辅助性T细胞1 (Thl)和辅助性T细胞2 (Th2)反应平衡,可使ITP患者Th1极化状态部分改善。     

山奈酚对小鼠T淋巴细胞体外活化、增殖和细胞周期的影响

目的:研究山奈酚(KA)对小鼠T细胞体外活化、增殖和细胞周期的影响,并对其免疫调节作用进行初步探讨.方法:分离小鼠淋巴结细胞,加入多克隆刺激剂刀豆蛋白A(ConA)进行刺激,以不同终浓度的KA与T细胞共培养.流式细胞术结合双色荧光抗体染色,检测T细胞早期活化抗原CD69的表达;MTT法检测KA对T细胞增殖的影响;用碘化丙锭(PI)染色分析T细胞的细胞周期.结果:终浓度为10、20和40 μmol/L的KA可以显著抑制ConA刺激的T细胞CD69的表达,由ConA组的(39.11±1.17)%,分别降低为(30.64±0.23)%、(27.95±0.04)%和(5.63±0.37)%(P<0.05);MTT法结果显示,KA对ConA诱导的小鼠T淋巴细胞增殖,具有明显的抑制作用(P<0.05),且呈剂量依赖性;PI染色结果显示,随着KA浓度的增加,均能明显阻止淋巴细胞进入S期和G2/M期.结论:KA可显著抑制ConA刺激下的小鼠T淋巴细胞体外活化和增殖;它能抑制T淋巴细胞进入细胞分裂期.     

慢性乙型肝炎患者T细胞功能的研究

本文以31例慢性乙型肝炎患者为研究对象,用CD系列单克隆抗体检测了患者外周T细胞亚群分型,观察ConA诱导的白细胞介素-2分泌功能,以及非特异性T细胞抑制功能(Ts)对B细胞抗体分泌的影响。结果表明,慢性乙肝患者体内存在T细胞免疫功能的异常,其外周血CD_4~+细胞比例低下,CD~+细胞比例增高,导致CD_4/CD_3比值下降,这种变化与HBV复制活跃的指标HBsAg~+密切相关。因此血清HBeAg~+是反映患者外周血T细胞亚群变化较敏感的指标。此外慢性乙肝患者T细胞产生IL-2的功能明显障碍,同时伴有ConA诱导的Ts功能低下,这种功能的异常与外周血CD_4~+与CD_8~+细胞亚群的变化无明显的统计相关性。     

双黄连粉针剂对小鼠T淋巴细胞体外活化与增殖的影响

目的:探讨双黄连粉针剂(以下简称SHL)对小鼠T淋巴细胞的体外活化和增殖的影响.方法:MTT法检测SHL对小鼠淋巴细胞的毒副作用;双色荧光抗体染色技术结合流式细胞术分析SHL对小鼠T淋巴细胞在多克隆刺激剂(ConA)刺激下体外活化抗原CD69表达的影响;MTT法以及羧基荧光素乙酰乙酸(CFDA-SE)标记技术结合流式细胞术分析SHL对小鼠T淋巴细胞在ConA诱导下体外增殖的影响.结果:SHL对小鼠淋巴结来源的淋巴细胞毒副作用非常小;终质量浓度为60、 80、 100、 120 mg/L的SHL对ConA刺激下的T淋巴细胞体外活化抗原CD69表达具有抑制作用(P<0.01);MTT法和CFDA-SE染色法都显示, 终质量浓度为60、 80、 100、 120 mg/L的SHL对ConA诱导的T淋巴细胞增殖作用具有明显的抑制作用(P<0.01).结论:SHL对小鼠T淋巴细胞的体外活化和增殖具有明显的抑制作用.     

TPO-Ab及TGA与淋巴细胞亚群联检在AITD中的临床价值

目的:探讨自身免疫性甲状腺疾病(AITD)发病与甲状腺自身抗体之间存在的作用关系.方法:分别采用电化学发光法(ECL)检测了甲状腺过氧化物酶抗体(TPO-Ab)水平,采用放射免疫分析检测了89例男性及81例女性AITD患者和相应正常对照组的甲状腺球蛋白抗体(TGA),并采用免疫荧光标记单克隆抗体和流式细胞仪联检T淋巴细胞亚群(CD4 /CD8 )的活性.结果:AITD患者TPO-Ab以及TGA的水平均显著高于对照组(P＜0.01),相关分析显示,抗体水平与淋巴细胞T细胞亚群(CD4 /CD8 )活性变化没有明显相关(P＞0.05).结论:甲状腺自身抗体的水平变化可作为AITD部分病因的推测和提示.     

Influx of recent thymic emigrants into autoimmune thyroid disease glands in humans

Autoimmune thyroid diseases (AITD) are considered as prototypic organ-specific autoimmune diseases, yet their underlying aetiology remains poorly understood. Among the various pathophysiological mechanisms considered, a failure of central tolerance has received little attention. Here we present evidence in favour of dysregulated thymic function playing a role in AITD. Flow-cytometric analyses conducted in peripheral blood lymphocytes from 58 AITD patients and 48 age- and-sex-matched controls showed that AITD patients have significantly higher blood levels of CD4(+)CD45RA(+), CD4(+)CD31(+) and CD4/CD8 double-positive T lymphocytes, all markers of recent thymic emigrants (RTE). In addition, the alpha-signal joint T cell receptor excision circles (TRECs) content (a molecular marker of RTEs) was higher in the group of AITD patients older than 35 years than in age-matched controls. This was independent from peripheral T cell expansion as assessed by relative telomere length. Comparisons of TREC levels in peripheral blood lymphocytes and intrathyroidal lymphocytes in paired samples showed higher levels within the thyroid during the initial 30 months of the disease, indicating an influx of RTE into the thyroid during the initial stages of AITD. Additionally, a lack of correlation between TREC levels and forkhead box P3 expression suggests that the intrathyroidal RTE are not natural regulatory T cells. These results uncover a hitherto unknown correlation between altered thymic T cell export, the composition of intrathyroidal T cells and autoimmune pathology.     

The immunoregulatory disturbance in autoimmune thyroid disease

There is now considerable evidence for a genetically induced antigen-specific defect in suppressor T lymphocytes as the basis for AITD, derived from several laboratories and via different types of experimental techniques. In addition, there is now evidence for additive effects on reducing generalized suppressor T lymphocyte numbers and/or function by environmental factors as well as hyperthyroidism itself, and these effects would be superimposed upon the organ-specific defect. Such effects on generalized suppressor T lymphocyte numbers may act as precipitating and self-perpetuating factors, in Graves' disease at least. Presentation of the antigen by the thyroid cell via HLA-DR expression on its membrane does occur as a result of interferon gamma production by T lymphocytes. This in turn appears to be secondary to the initial specific immune assault and is not a primary inductive step. However, it may be important as an amplifying intermediate factor but cannot perpetuate the process in the absence of the underlying immune disorder. There is, however, no evidence for an underlying antigenic abnormality or stimulus in human autoimmune thyroid disease, and the initiating event would appear to be due to perturbation of the generalized immune system superimposed on the organ-specific abnormality. Variations in the serological and clinical expression of AITD would appear to depend on the severity of the original organ-specific disturbance in suppressor T lymphocyte function, plus the added factor of environmental influences playing upon generalized suppressor T lymphocyte function and numbers. Remissions in Graves' disease brought about by antithyroid drugs may well be via their effect on modulating the thyroid cell activity; this will then reduce thyrocyte-immunocyte signalling, allowing remission to occur in those patients with a partial organ-specific defect in suppressor T lymphocytes.     

Decreased suppressor T cell activity in patients with hepatic cirrhosis (HC).

Hypergammaglobulinaemia (HGG) is frequently found in patients with hepatic cirrhosis (HC). Using an assay system of in vitro PWM-stimulated immunoglobulin (Ig) production, the amounts of IgG, IgA, and IgM produced by peripheral blood lymphocytes (PBL) from 15 HBs Ag-negative patients with HC and from 16 age-matched healthy subjects were quantitated by radioimmunoassay. We found that PBL from patients with HC produced significantly greater amounts of IgG (P less than 0.05) but not IgA or IgM than did those from control subjects. This increased IgG production by PBL from patients with HC was attributed to enhanced T helper activity and not to enhanced B cell function. We also searched for defects in naturally occurring suppressor T cell activity which is sensitive to irradiation. Irradiation-induced enhancement for IgG production was significantly lower in patients with HC compared with age-matched control subjects (P less than 0.01). Similarly, we examined the effect of Con A-induced suppressor T cells on the in vitro PWM-stimulated IgG production by allogeneic PBL and observed the decrease of Con A-induced suppressor T cell activity in patients with HC (P = 0.01). We conclude, therefore, that the increased serum levels of Ig, particularly IgG in patients with HC may result from in part on the basis of depressed ability of naturally occurring suppressor T cells or Con A-induced suppressor T cells to suppress Ig production.     

Helper and suppressor T lymphocyte function in severe alcoholic liver disease.

The immune regulatory T cell status of patients with severe alcoholic liver disease (ALD) was investigated. Using monoclonal antibodies to identify lymphocyte subsets in 22 patients, a significant decrease in the percentage of T suppressor/cytotoxic cells (P less than 0.01) and increase in the percentage T helper/inducer population (P less than 0.05) was observed when the results were compared with 20 normal controls. However, when absolute numbers of these lymphocyte subsets were calculated the patient group did not differ significantly from the controls. Further studies revealed T immunoregulatory cell function to be normal. Concanavalin A induced suppressor cells resulted in equivalent inhibition of autologous cell mitogen responsiveness in the patient and control groups. In addition, purified patient T lymphocytes were demonstrated to provide normal help to and manifest normal suppression of IgG, IgA and IgM synthesis by allogeneic B cells. When spontaneous immunoglobulin synthesis by circulating mononuclear cells was investigated, a significant increase in IgA synthesis was found in the ALD patients (P less than 0.05). These results suggest that T cell immunoregulation is normal in patients with ALD and a defect in this system is not responsible for the increased synthesis of immunoglobulin observed in ALD.     

Antigen stimulated IgM secretion by circulating B lymphocytes in patients with benign and malignant IgG gammopathy. Relationship to stage of disease.

In the present investigation antigen-driven (sheep red blood cells, SRBC) IgM antibody secretion by B lymphocytes of 22 MM (IgG kappa) patients and 15 patients with IgG kappa monoclonal gammopathy of undetermined significance (MGUS) was studied and compared to that of 20 age-matched healthy controls and five patients with Waldenstrum (IgM) macroglobulinemia (WM). Antibody production by cultured lymphocytes of MM and WM patients was significantly decreased, whereas in MGUS patients it fell within normal limits. We could divide MM patients into three subsets: those who secrete normal amounts of IgM in vitro (patients with the stable type); a second subset of patients whose B lymphocytes secreted low amounts of IgM (MM patients in remission); and a third subset of patients who manifested an intrinsic block of B cell differentiation into IgM-secreting cells (patients with the progressive stage). Sephadex G-10 adherent suppressor cells had no effect on antibody production in the stable and progressive types of disease, whereas in the remission stage they markedly inhibited IgM secretion. Measurement of antigen-driven IgM antibody secretion might help in the differentiation of MGUS and stable (smouldering) MM from frank (progressive) MM at diagnosis. It may also provide a tool for monitoring progression of disease and response to therapy.     

Regulation of the Immune Response to Hepatitis B Virus and Human Serum Albumin

Peripheral B and T cells sensitized to human serum albumin (HSA) were found in a cohort of patients chronically infected with hepatitis B virus (HBV). Throughout this study, two groups of symptomatic chronic hepatitis B surface antigen (HBsAg) carriers could be distinguished, characterized by divergent T-cell regulation of the spontaneous IgG anti-HSA secretion. Patients in a quiescent phase of the disease [patients with chronic persistent hepatitis B (CPH), anti-HBe reactivity and absence of viral replication, group A] had circulatory in vivo HBsAg-HSA preactivated B cells with the capacity to secrete spontaneously IgG antibodies with specificity for HSA when isolated and cultured. The addition of autologous T lymphocytes at a T/B-cell ratio of 8.0 suppressed the spontaneous anti-HSA secretion. In contrast, patients in an active stage of the disease exhibited in vivo preactivated T cells exerting helper cell functions on the spontaneous IgG anti-HSA secretion. Memory T cells, sensitized to low concentrations of HBsAg-HSA with disparate regulatory functions, were also detectable in the two groups of patients.     

Regulation of immunoglobulin secretion by T lymphocytes in human malaria

In vitro studies were carried out on the nature of immunoglobulin synthesis and secretion by peripheral blood mononuclear leukocytes (PBMLs) and on the function of T and B cells from malaria patients. The mean values of secreted IgG and IgM concentrations of 22 malaria patient PMBLs were significantly higher than those of 20 normal PBMLs. When the suppressor T cell activity and the function of B cells in response to suppressor T cells were assayed by the cell co-culture technique, it was found that there was a decrease in suppressor T cell activity and the B cell function in response to normal suppressor T cells in malaria patients. The defects of these T and B cell functions may play some role in the immunological abnormalities seen in some malaria patients.     

Increased IgG secretion by unstimulated mononuclear cells in active multiple sclerosis and functional assessment of the T8 subset

Unseparated mononuclear cells (10(5) cells/well) were cultured both in the presence and absence of pokeweed mitogen (PWM), and IgG secretion was measured by radioimmunoassay. In unstimulated cultures, levels of IgG secretion were found to be higher in a group of patients with multiple sclerosis (MS) than in control groups of healthy individuals or patients with other neurologic diseases (OND). By contrast, PWM-induced IgG secretion was similar in MS patients and in controls. In MS patients, levels of IgG secretion greater than 2500 ng/ml in unstimulated cultures were present in 29 (58%) of 50 patients with active disease and in only 3 (14%) of 21 patients with inactive MS (P less than 0.01; MS active vs inactive). Furthermore, levels of IgG secretion in unstimulated cultures were higher in patients who had abnormalities of circulating T-cell subsets consisting of reduced numbers of suppressor/cytotoxic (T8) cells and elevated helper:suppressor (T4:T8) ratios. In additional experiments using isolated populations of T-cell subsets, T8 cells from MS patients who had low percentages of circulating T8 cells were found to suppress PWM-induced IgG secretion by autologous cells to a similar extent as controls, suggesting that in vitro, T8 cells function normally in these patients. In vitro IgG secretion by unstimulated mononuclear cells in MS appears to be a further reflection of abnormal immune regulation in this disease.     

Defective in vitro immunoglobulin production in response to pokeweed mitogen in patients with Hodgkin's disease pretreatment and in remission

In vitro production of IgG and IgM from peripheral blood lymphocytes and B-cell enriched fractions was assessed in a group of Hodgkin's disease (HD) patients and normal controls using pokeweed mitogen (PWM) stimulation. Our studies demonstrated a significant (P less than 0.01) reduction in the absolute number of helper (OKT4 positive) T cells and a significant alteration in the helper/suppressor T-cell ratio (0.89 +/- 0.15) compared to normal (1.83 +/- 0.31). Results from PWM stimulation experiments demonstrated that HD patients produced significantly lower IgG (P less than 0.01) and IgM (P less than 0.01) levels than controls. Synthesis of IgM but not IgG induced by PWM was subnormal after addition to patient B-cell cultures of autologous irradiated T cells or allogeneic irradiated normal T lymphocytes. Irradiated T cells from HD patients were as effective as normal T cells in helping PWM induced IgG and IgM synthesis by normal B cells. Our results suggest that in HD impaired circulating B-cell function is partly due to T-suppressor cell activity and furthermore that B-cell subpopulations producing different immunoglobulin isotypes may either be defective or vary in their susceptibility to T-cell suppression.     

Severe combined immunodeficient (SCID) mice: a model for investigating human thyroid autoantibody synthesis

We have studied the ability of lymphocytes from the blood, thyroid and lymph nodes of patients with autoimmune thyroid disease (AITD) to produce autoantibodies to thyroglobulin (Tg) and/or thyroid peroxidase (TPO) in SCID mice. Human IgG class Tg and/or TPO antibodies were detectable in plasma from SCID mice 7 days after transfer of 15-25 x 10(6) cells/mouse and the highest levels were recorded 2-3 weeks later. In contrast, Tg and/or TPO antibodies were undetectable in recipients of lymphocytes from thyroid antibody negative controls. AITD thyroid lymphocytes produced the most antibody in recipient mice and lower levels were observed in recipients of AITD blood and lymph node lymphocytes. The amounts of Tg and/or TPO antibody detected were in accordance with the ability of thyroid and lymph node lymphocytes to secrete these autoantibodies spontaneously in culture (indicating the presence of cells activated in the patient) and with the capacity of blood lymphocytes (probably B memory cells) to secrete Tg and/or TPO antibodies in culture in response to pokeweed mitogen. Tg antibodies in plasma from SCID recipients of thyroid lymphocytes were of subclasses IgG1, IgG2 and IgG4 and the proportions closely resembled those of the donor's serum Tg antibodies. Blood lymphocytes transferred to SCID recipients were also able to produce Tg antibodies of subclasses 1, 2 and 4 but the subclass distribution varied between mice and the reason for this is not clear at present. Since SCID mice provide an environment in which B lymphocytes from patients with AITD can be activated without mitogen to secrete thyroid antibodies, this model will provide a powerful system for elucidating the mechanisms regulating the secretion of human antibodies to Tg and TPO.