脑型疟免疫病理学机制的研究进展

了解脑型疟发病机制最新进展,可为防治脑型疟、降低死亡率提供依据。研究发现鼠脑型疟是一种多因素参与的致命性的免疫病理性疾病,中枢神经系统血脑屏障渗透性增加、星形胶质细胞变性导致其支持功能的丧失、小胶质细胞与淋巴细胞分泌的各种细胞因子和单核/巨噬细胞相结合共同促使中枢神经系统功能紊乱,诱发脑型疟。在探讨人类脑型疟致病机制时应考虑中枢神经系统内胶质细胞和细胞因子的作用。     

脑型疟免疫病理学机制的研究进展

了解脑型疟发病机制最新进展，可为防治脑型疟、降低死亡率提供依据。研究发现鼠脑型疟是一种多因素参与的致命性的免疫病理性疾病，中枢神经系统血脑屏障渗透性增加、星形胶质细胞变性导致其支持功能的丧失、小胶质细胞与淋巴细胞分泌的各种细胞因子和单核／巨噬细胞相结合共同促使中枢神经系统功能紊乱，诱发脑型疟。在探讨人类脑型疟致病机制时应考虑中枢神经系统内胶质细胞和细胞因子的作用。     

血脑屏障的破坏是脑型疟形成的标志吗?

在发展中国家 ,脑型疟疾是一个主要的杀手 ,但是对其病因知道的仍然很少。在此对尸解、体外试验及动物模型研究中提供的最新证据作一介绍 ,以阐明血脑屏障的破坏在脑型疟疾中的显著作用 ,在重症疟疾中 ,血脑屏障完整性的破坏将导致大脑血管的渗漏。了解该病如何发生以及导致昏迷的病因 ,以便为选择脑型疟疾的对症治疗提供对策参考     

小胶质细胞α7-nAChR表达及意义

目的观察巨噬细胞烟碱型乙酰胆碱受体（α7-nAChRR）在体外培养的小胶质细胞中的表达,为进一步研究其作用提供理论依据。方法采用RT-PCR及细胞免疫荧光双标法,用针对α7-nAChRR特异性的引物进行PCR,分析α7-nAChRR在小胶质细胞中的表达。结果可扩增出450 bp目的条带;细胞免疫荧光双标分析显示,小胶质细胞抗CD11b/c和抗α7-nAChRR染色均呈阳性。结论α7-nAChRR在体外小胶质细胞中能正常表达;此可能是小胶质细胞发挥作用的分子学基础。     

血脑屏障的破坏是脑型疟形成的标志吗？

在发展中国家，脑型疟疾是一个主要的杀手，但是对其病因知道的仍然很少。在此对尸解、体外试验及动物模型研究中提供的最新证据作一介绍，以阐明血脑屏障的破坏在脑型疟疾中的显著作用，在重症疟疾中，血脑屏障完整性的破坏将导致大脑血管的渗漏。了解该病如何发生以及导致昏迷的病因，以便为选择脑型疟疾的对症治疗提供对策参考。     

神经血管单元在脑小血管病中的作用

脑小血管病（cerebral small vessel disease, CSVD）是临床常见的脑血管病,其起病隐匿且临床表现多样。研究表明,神经血管单元（neurovascular unit, NVU）功能失衡与血管内皮功能障碍、血脑屏障通透性改变、胶质细胞活化等病理生理学过程存在多向作用和反复激活现象,在炎症和免疫...     

小胶质细胞与脑出血

小胶质细胞是脑内的主要免疫效应细胞，正常时处于“休眠状态”，无吞噬能力。脑出血后，小胶质细胞迅速活化、增殖，发挥巨噬细胞的吞噬效应，并通过产生神经毒性分子和神经营养因子发挥双重效应。蛋白激酶C、核因子KB和丝裂素活化蛋白激酶的活化是脑出血后小胶质细胞产生神经毒性分子的内在机制。在一定时间窗内适当抑制小胶质细胞的活化，能减轻其细胞毒作用，改善预后。     

2型糖尿病大鼠脑缺血再灌注后S-100β蛋白的表达

目的 通过测定S-100β蛋白在脑缺血再灌注和2型糖尿病合并脑缺血再灌注大鼠脑内不同时间点的表达,探讨2型糖尿病对再灌注损伤的影响.方法 利用免疫组织化学方法 检测脑缺血再灌注模型和2型糖尿病合并脑缺血再灌注大鼠脑内不同时间点星形胶质细胞的活化情况.结果 2型糖尿病合并脑缺血再灌注大鼠脑内不同时间点S-100β表达较单纯缺血再灌注组增加,而且表达高峰出现时间提前.结论 糖尿病可能通过反应性星形胶质细胞的活化加重了脑缺血再灌注损伤.     

周细胞在脑小血管病发病机制中的作用

周细胞位于脑毛细血管内皮细胞、星形胶质细胞和神经元之间,具有维持血脑屏障完整性、调节脑血流量等多种功能。周细胞丢失可导致脑微循环功能障碍和血脑屏障破坏等病理过程,并与多种疾病有关,但目前其与脑小血管病的相关性研究较少。文章主要对周细胞在脑小血管病发病机制中的作用进行了综述。     

小鼠脑缺血后星形胶质细胞和小胶质细胞的活化规律比较

目的比较小鼠脑缺血后星形胶质细胞和小胶质细胞的活化规律。方法采用改良线栓法制备小鼠大脑中动脉阻塞再灌注局灶性脑缺血损伤模型。昆明小鼠48只,随机分为假手术组24只和脑缺血组24只。脑缺血组缺血3h后再分为再灌注1、3、7和14d,每个时间点6只。再灌注结束后,取脑作HE染色观察脑组织病理改变,免疫组织化学染色法检测星形胶质细胞胶质纤维酸性蛋白(GFAP)和小胶质细胞离子钙接头蛋白1(Iba1)的表达。结果与缺血再灌注1d比较,脑缺血组缺血再灌注3、7、14d皮质缺血周边区的GFAP阳性产物显著增加[(699.22±160.82)μm2/HP,(1817.97±290.88)μm2/HP,(2831.64±481.38)μm2/HP vs(33.13±7.45)μm2/HP,P0.01]。脑缺血组缺血再灌注1d皮质缺血周边区出现以"分支状"为主的Iba1阳性小胶质细胞,3、7d活化的小胶质细胞显著增多并表现为"灌木样"细胞,14d后活化小胶质细胞呈现"阿米巴样"细胞。结论脑缺血再灌注损伤时,小胶质细胞和星形胶质细胞均出现活化,但小胶质细胞活化出现得更早;星形胶质细胞活化只出现在缺血周边区,而活化的小胶质细胞可从缺血周边区向缺血中央区迁移。     

Germinal centre and marginal zone B cells expand quickly in a second Plasmodium chabaudi malaria infection producing mature plasma cells

Antibodies and B cells are critical in the protective immune response to the blood stage of the malaria parasite, Plasmodium chabaudi. However, little is known about the development of memory B cells and their differentiation into plasma cells during infection or after re-infection. Here we have shown that B cells with phenotypic characteristics of memory cells (CD19 ⁺ IgD⁻ CD38 ⁺ , IgG1 ⁺ ) are generated in a primary Plasmodium chabaudi chabaudi infection of mice. In addition, we observed that germinal centre cells (CD19⁺, GL7⁺, MHCII^hi) and Marginal Zone B cells (CD19⁺CD23⁻IgD⁻) show faster expansion on re-infection than in the primary, though other subsets do not. Interestingly, though both IgM⁻ and IgM⁺ memory cells are produced, IgM⁺ memory cells do not expand on second infection. The second infection quickly produced mature bone marrow plasma cells (intracellular Ig^hi, CD138^hi, CD9⁺, B220⁻), compared to primary infection; which generates a very large population of immature splenic plasma cells (B220+). This analysis suggests that a memory B cell population is generated after a single infection of malaria, which on re-infection responds quickly producing germinal centres and generating long-lived plasma cells making the second encounter with parasite more efficient.     

Protective CD4+ T-cell lines raised against Plasmodium chabaudi show characteristics of either Th1 or Th2 cells

Splenic T-lymphocyte lines were established in vitro from Plasmodium chabaudi-infected NIH mice on days 16 and 20 of a primary infection, and from mice after two or three infections. Each line responded specifically to stimulation with a lysed soluble extract of P. chabaudi-infected erythrocytes (pRBC), and displayed a CD4⁺ (L3T4⁺) surface phenotype. Both the day 16 and 20 cell lines, when stimulated in vitro, secreted interleukin-2 (IL-2) and γ-interferon (IFN-γ), indicative of their belonging to the T helper 1 (Th1) CD4⁺ subset. In contrast, both lines derived from reinfected mice secreted interleukin-4 (IL-4) and provided helper activity in antibody production to P. chabaudi in vitro, and thereby had the characteristics of Th2 cells. All four T-cell lines provided significant protection to naïve mice infected with P. chabaudi. In immuno-compromised mice, the day 16 T-cell line was as protective as in naïve mice whereas the cell line from mice infected twice required the additional transfer of mature naïve splenic B cells to provide protection comparable to that seen in the immunocompetent naïve recipients. The results establish that protective immunity to P. chabaudi may be associated with the induction of CD4⁺ Tcells of either the Th1 or Th2 subset which confer protection against this malaria parasite by mechanisms independent of, and dependent upon, B-cell involvement, respectively.     

Flow cytometric identification of candidate normal stem cell populations in CD45-negative B-cell precursor acute lymphoblastic leukaemia

CD45-negative B-cell precursor acute lymphoblastic leukaemia (ALL) provides a unique model to study the stem cell compartment in ALL as leukaemic CD34-positive cells, unlike their normal counterparts, do not express CD45. By increasing the number of events analysed to 10⁶, storing only the events in the region of interest (storage gate), using appropriate isotype controls and stringent washing procedures, a flow cytometric protocol was established to characterize rare CD34⁺CD19⁻ events. In eight of 12 patients (67%) with CD45-negative B-cell precursor ALL, a distinct CD34⁺CD19⁻CD45⁺ candidate normal stem cell population could be detected. In one patient analysed by four-colour staining, the CD34⁺CD19⁻CD45⁺ cells, unlike the CD45-negative leukaemic cells, expressed CD117 (c-kit), providing further evidence that these cells represent residual non-leukaemic normal cells. By multiparameter analysis, this population of candidate normal stem cells could be separated from contaminating leukaemic CD34⁺CD19⁻CD45⁻cells, which were detected in 11 of the 12 patients within the CD34⁺CD19⁻ compartment.     

肿瘤患者化疗前后外周血NK/T及Treg细胞比例分析

目的探讨肿瘤患者化疗前后,外周血免疫激活细胞及免疫抑制细胞比例变化。 方法本研究通过分析38例健康人外周血NK/T细胞及Treg细胞流式分析结果,并跟踪本中心140例常见肿瘤患者(结直肠癌31例、胃癌21例、乳腺癌27例、肺癌61例),发病前后、化疗疗程中外周血中的NK/T细胞及Treg细胞比例。 结果恶性肿瘤患者外周血中Treg细胞比例显著高于健康对照组分别为(6.95%±8.96%)、(4.25%±2.59%),P<0.05, NK细胞比例也显著高于健康人分别为(18.56%±9.19%)、(12.37%±6.24%),P<0.01。因统计病例数目有限,对69例肿瘤患者化疗的后续随访中发现,随着化疗进程,NK细胞以及Treg的比例变化无统计学意义,但在结直肠癌及胃癌中,Treg细胞比例可见先降低后升高的趋势。 结论肿瘤患者外周血Treg细胞比例高于健康人,在化疗过程中NK细胞比例以及Treg细胞比例均高于化疗前水平。随着本研究的继续深入,可能进一步证实Treg细胞在肿瘤中富集,形成免疫抑制微环境,是通过抑制CD4^＋、CD8^＋T淋巴细胞及NK细胞的肿瘤杀伤效应,介导肿瘤免疫逃逸的可能。     

持续低效血液透析滤过对重症急性胰腺炎患者肠黏膜屏障功能及免疫功能的影响

目的 评价持续低效血液透析滤过（SLEDF）对重症急性胰腺炎（SAP）患者肠黏膜屏障功能及免疫功能的影响。方法 将51例SAP患者随机分为持续静脉静脉血液滤过（CVVH）组25例和SLEDF组26例,在常规治疗基础上分别接受CVVH和SLEDF治疗。比较两组患者预后、血、尿淀粉酶恢复正常时间、治疗前和治疗第2、4、8、14d血D-乳酸、内毒素（ET）、二胺氧化酶(DAO)、CD3⁺、CD4⁺、CD8⁺T淋巴细胞水平、CD4⁺/CD8⁺T淋巴细胞比值及血液净化相关并发症发生情况。结果 两组患者死亡率、血、尿淀粉酶恢复正常时间比较差异均无统计学意义,血D-乳酸、ET、DAO、CD3⁺、CD4⁺、CD8⁺T淋巴细胞水平和CD4⁺/CD8⁺T淋巴细胞比值在治疗前和治疗第2、4、8、14d比较差异均无统计学意义（P>0.05）。两组患者治疗第4、8、14d D 乳酸、ET和DAO水平均较同组治疗前降低,第8、14d均较同组治疗第4d降低（P＜0.05）。两组患者治疗第4、8、14d的CD3⁺、CD4⁺、CD8⁺T淋巴细胞水平和CD4⁺/CD8⁺T淋巴细胞比值均较同组治疗前升高,第8、14d均较同组治疗第4d升高（P＜0.05）;两组患者治疗第4、8d的CD8⁺T淋巴细胞水平较同组治疗前降低,第8、14d较第4d降低（P＜0.05）。结论 SLEDF和CVVH改善SAP患者肠道屏障功能障碍和免疫功能异常的作用相似,其中SLEDF操作方便,医疗费用低,值得临床推广。     

结核分枝杆菌感染对BALB/c小鼠B细胞发育分化的影响

目的 探讨结核分枝杆菌感染对小鼠B淋巴细胞分化发育的影响。方法 建立Mtb感染BALB/c小鼠模型,在感染早期(4周)及晚期(8周)分别取小鼠骨髓细胞及脾脏细胞,或经培养后,荧光抗体染色,用流式细胞术对感染早期及晚期小鼠的B细胞表型进行分析,设生理盐水处理的小鼠作为对照。结果 Mtb感染组与对照组比较,pro-B细胞(CD45R⁺CD43⁺)(4周:t=2.886,P<0.05)、未成熟B细胞(CD45R⁺IgM⁺IgD^-)(4周:t=4.760,P<0.05)减少,骨髓成熟B细胞(CD45R⁺IgM^+/-IgD⁺)(4周:t=-3.485,P<0.05;8周:t=-2.594,P<0.05)与脾脏成熟B细胞(CD45R⁺IgMlowIgDhi)(4周:t=-2.275,P<0.05;8周:t=-2.97,P<0.05)增多;小鼠脾脏B细胞活化分子CD69表达升高(4周:t=-2.271,P<0.05;8周:t=-2.052,P<0.05);小鼠脾脏记忆性B细胞 (CD45R⁺CD27⁺IgD^+/-)升高(4周:t=-4.203,P<0.05;8周:t=-5.280,P<0.05)。结论 Mtb感染能影响B细胞的分化发育,促使B细胞向成熟细胞分化,并能促使B细胞活化,使机体更有利于抗结核的感染。     

Modification of Lymphocyte Subsets in the Intestinal-Associated Immune System and Thymus by Chronic Ethanol Consumption

Modification of the mucosa-associated intestinal immune system of female C57BL/6 mice was studied during consumption of the Lieber-DeCarli diet supplemented with 5% v/v ethanol or laboratory chow with ethanol (20% w/v) in the drinking water. All groups received ethanol for 11 weeks. Mice fed the Lieber-DeCarli diet had fewer CD8⁺ cells/villus than the chow-fed controls. Mice that received ethanol in the drinking water had fewer IgA-containing cells and CDB⁺ cells than controls. There were no differences in the number of cells in the mesenteric lymph nodes between ethanol-treated mice and their respective controls. Nevertheless, chow-fed control mice had more cells than those fed the Lieber-DeCarli control diet. Although no differences were detected in the percentages of CD4⁺, CD8⁺, LECAM-1⁺, and LECAM-1⁺ CD4⁺ cells, there was a decrease in the percentage of LECAM-1⁺ CD8⁺ cells in ethanol-fed mice when compared with their Lieber-DeCarli controls. Mice receiving ethanol in the drinking water showed alterations in the CD4 CD45RC subsets and in the CD8 CD45RC subsets. Similar results were observed in mice receiving Lieber-DeCarli diets alone or supplemented with ethanol. The low dose, chronic exposure of dietary ethanol in the Lieber-DeCarli-fed mice did not significantly affect the numbers of various thymocyte subsets. But, a decrease in the percentage of CD4^- CD8⁺ cells was observed in the thymus of mice receiving ethanol in the drinking water. Chronic ethanol consumption caused significant decreases in the number of CD8⁺ and IgA⁺ cells in the intestinal lamina propria, important in mucosal immune defenses.     

CD3-induced T-cell activation in the bone marrow of myeloma patients: major role of CD4+ cells

Summary. A large expansion of activated T cells (CD3⁺CD25⁺) with the potential to act as anti-tumour effector cells is inducible in multiple myeloma (MM) patients by culturing bone marrow mononuclear cells (BMMCs) with the anti-CD3 monoclonal antibody (mAb) OKT3. The aim of this study was to provide a greater characterization of CD3-activated T cells. On day 6, most T cells coexpressed the CD1 la, CD18, CD54, CD45R0 antigens and consisted of activated (CD25⁺) CD4⁺ and CD8⁺ cells in nearly equal proportions. Kinetics studies showed that CD4⁺CD25⁺ cells proliferated more rapidly and peaked earlier than CD8⁺CD25⁺ cells. When experiments were performed with purified subpopulations by removing CD4⁺ cells (resulting in CD8⁺ BMMCs) or by removing CD8⁺ cells (resulting in CD4⁺ BMMCs), T-cell activation and autologous plasma cell decrease were observed in CD4⁺ BMMCs only. Transwell cultures showed that CD4 help was necessary to make CD8⁺ BMMCs susceptible to CD3 stimulation. Relevant amounts of IL-2 were found in the supernatants of CD4⁺ BMMCs cultures, whereas no secretion of IL-4 was detected, indicating a Thl-like profile of CD3-activated CD4⁺ cells.
These data indicate that CD4⁺ cells proliferate earlier and provide optimal help to induce the subsequent expansion of CD8+ cells after CD3 stimulation of MM BMMCs. Adequate stimulation of CD4⁺ cells is therefore essential in any strategy aiming to recover T-cell-mediated immunity in MM.     

Polyclonal T-cell responses to Plasmodium falciparum gametocytes in malaria nonexposed donors

Human peripheral blood T-cells mount vigorous proliferative responses to asexual stage parasites of P. falciparum regardless of whether the donor has been exposed to the parasite. Here using highly purified P. falciparum gametocytes we show that the same is also true for this stage of the parasite. Gametocytes, like immature trophozoites, preferentially activate CD4⁺ T cells. γδ T-cell activation, commonly observed in response to mature schizonts or supernatants from asexual-stage cultures, does not occur. Furthermore, the CD4⁺ T-cell blasts stimulated by gametocytes show a similar pattern of T-cell receptor variable region (TCRVβ) usage to those stimulated by asexual parasites and there is no preferential usage of TCRVβ elements. The CD4⁺ T-cell precursor frequencies for gametocyte and asexual trophozoite responses are remarkably similar. 'Cross-reactivity' of gametocyte and asexual stage responses was confirmed by selective depletion of cells responding to particular stages of the parasite using the cytostatic drug cytosine arabinoside (Ara-C). These results suggest that the CD4⁺ T-cell responses from malaria nonexposed donors are common to gametocytes and asexual trophozoites.     

Intravenous administration of melatonin reduces the intracerebral cellular inflammatory response following transient focal cerebral ischemia in rats

We have previously shown that exogenous melatonin improves the preservation of the blood-brain barrier (BBB) and neurovascular unit following cerebral ischemia-reperfusion. Recent evidence indicates that postischemic microglial activation exaggerates the damage to the BBB. Herein, we explored whether melatonin mitigates the cellular inflammatory response after transient focal cerebral ischemia for 90 min in rats. Melatonin (5 mg/kg) or vehicle was given intravenously at reperfusion onset. Immunohistochemistry and flow cytometric analysis were used to evaluate the cellular inflammatory response at 48 hr after reperfusion. Relative to controls, melatonin-treated animals did not have significantly changed systemic cellular inflammatory responses in the bloodstream (P > 0.05). Melatonin, however, significantly decreased the cellular inflammatory response by 41% (P < 0.001) in the ischemic hemisphere. Specifically, melatonin effectively decreased the extent of neutrophil emigration (Ly6G-positive/CD45-positive) and macrophage/activated microglial infiltration (CD11b-positive/CD45-positive) by 51% (P < 0.01) and 66% (P < 0.01), respectively, but did not significantly alter the population composition of T lymphocyte (CD3-positive/CD45-positive; P > 0.05). This melatonin-mediated decrease in the cellular inflammatory response was accompanied by both reduced brain infarction and improved neurobehavioral outcome by 43% (P < 0.001) and 50% (P < 0.001), respectively. Thus, intravenous administration of melatonin upon reperfusion effectively decreased the emigration of circulatory neutrophils and macrophages/monocytes into the injured brain and inhibited focal microglial activation following cerebral ischemia-reperfusion. The finding demonstrates melatonin's inhibitory ability against the cellular inflammatory response after cerebral ischemia-reperfusion, and further supports its pleuripotent neuroprotective actions suited either as a monotherapy or an add-on to the thrombolytic therapy for ischemic stroke patients.