Immune responses that adapt the intestinal mucosa to commensal intestinal bacteria

Animals contain an enormous load of non-pathogenic bacteria in the lower intestine, which exploit an environment with a stable temperature and abundant carbon sources. Our load of bacteria outnumbers our own cells. In order to survive with such a high number of organisms in very close proximity to host tissues the intestinal mucosa and its immune system is highly adapted. Mucosal immune responses are induced by small numbers of live commensal organisms penetrating the Peyer's patches and persisting in dendritic cells (DC). These DC can induce immunoglobulin A+ (IgA+) B cells, which recirculate through the lymph and bloodstream to populate the lamina propria and secrete protective IgA. Because DC loaded with commensal bacteria do not penetrate further than the mesenteric lymph nodes, immune induction to commensals is confined to the mucosa, allowing strong mucosal immune responses to be induced whilst the systemic immune system remains relatively ignorant of these organisms.     

Long-term tolerance to skin commensals is established neonatally through a specialized dendritic cell subgroup

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B cells are involved in the modulation of pathogenic gut immune response in food-allergic enteropathy

Food enteropathies involve uncontrolled or hypersensitivity reactions to ingested nutrients and may result in IgE and T-helper type 2 (Th2) responses as in food allergy. However, the precise role of B cells in the development of food enteropathies remains uncertain. In this work, we used B cell-deficient mice (B KO) and a model of peanut sensitization to examine the involvement of B lymphocytes in the pathogenesis of food allergy. Results showed that priming of wild-type (WT) mice with peanut proteins induced specific IgG1 and IgE responses in serum, with edema, tissue destruction, epithelial exulceration and inflammatory infiltrate in the gut of sensitized and challenged (S + Peanut) WT animals. In contrast, there was no sera immunoglobulin detection and absence of tissue destruction in the gut of B KO mice, which presented moderate inflammatory infiltrate and villous enlargement after peanut challenge. These animals presented marked decrease in IL-4 and TNF-alpha and high levels of IL-10, TGF-beta, IL-12p40 and IFN-gamma mRNA in the gut. Moreover, the expression of CCL5, CCL11 and CXCL1 was reduced in the gut of B KO mice, in contrast to elevated messages of CCL2 or similar detection of Th1-related chemokines in S + Peanut WT mice. Finally, we provided evidence that B cells are necessary to the development of food-related enteropathies and induction of gut inflammation during allergic reactions to food.     

重建SCID小鼠免疫功能对肝癌抗原的体液免疫应答

为在ＳＣＩＤ小鼠体内获得人免疫Ｂ淋巴细胞，将１２～１４周龄的胎儿肝细胞（１～２）×１０１０／Ｌ腹腔注射于ＳＣＩＤ小鼠，然后再分次接种肝癌细胞。用ＥＬＩＳＡ法于第４，５，６周连续检测ＳＣＩＤ－ｈｕ小鼠血清人ＩｇＧ；用免疫组化ＡＢＣ法检测各种组织中的人淋巴细胞。各实验小鼠均检测到人ＩｇＧ的存在，最高为３９１μｇ／Ｌ，且随时间的延长呈上升趋势。在ＳＣＩＤ－ｈｕ小鼠肝、脾及腹腔接种瘤组织的周边，可见人ＣＤ３＋和ＣＤ２０＋的淋巴细胞。上述结果表明，用人胎肝细胞移植可在ＳＣＩＤ小鼠体内获得人淋巴细胞，并对人肝癌细胞抗原产生免疫应答，分泌一定水平的抗人肝癌的抗体。提示：用人胎肝细胞在ＳＣＩＤ小鼠体内可建立人免疫系统的部分功能。     

白色念珠菌感染免疫应答的研究进展

白色念珠菌的致病是其与机体免疫系统相互作用的结果.研究发现,白色念珠菌感染人体时,刺激机体产生固有免疫及特异性细胞免疫和体液免疫应答.其中特异性细胞免疫占主导地位.了解认识白色念珠菌感染的免疫应答对诊断、预防及治疗白色念珠菌感染具有重要意义.     

Differential T helper cell response in tuberculous pleuritis

Purpose: This study was conducted to understand the in vivo and in vitro immune responses and to find whether there exists any difference in the systemic and localized immune responses in tuberculous pleuritis. Methods: The in vivo levels of IFN-γand IL-4 were compared in plasma (BL) and pleural fluid (PF) of 47 tuberculous (TB) and 31 nontuberculous pleuritis (Non-TB) patients. In vitro cytokine response to various mycobacterial antigens was studied in 19 TB patients by ELISA. Both ex vivo and in vitro cytokine responses were further ascertained by intracellular cytokine staining on purified CD4⁺ T cells from pleural fluid mononuclear cells (PFMC) of 10 TB patients. Results: The ex vivo results showed a significant increase in IFN-γlevels and higher IFN-γ⁺ T cells in PF. On the other hand, in vitro results showed simultaneous increase in both IFN-γand IL-4 levels in the supernatants of antigen stimulated PFMC. Similarly antigen specific increase was observed in both IFN-γ⁺ and IL-4⁺ T cells in all cultured conditions. However, the percentile increase was more in IL-4 secreting T cells, significant for PPD stimulation (P 0.05), indicating that in vitro cellular response was dominated by Th2 type. Conclusions: These results showed a differential T-helper response in TB pleuritis suggestive of predominant Th1 in vivo and mixed response (Th1 and Th2) under in vitro conditions.     

编码TCR可变区的DNA免疫诱导BALB/C小鼠调节性免疫应答

目的：研究编码卵清白蛋白(OVA)T细胞克隆TCR Vα5．2或Vβ2.1的DNA免疫正常小鼠诱发调节性免疫应答。方法：用重组质粒pcDNA3．1-Vα5．2或pcDNA3．1-Vβ2.1免疫BALB／C小鼠,RT-PCR证实重组质粒能在体内和体外真核细胞中转录。^3H-TdR掺入法分析细胞增殖,^3H-TdR标记的靶细胞检测杀伤T细胞的杀伤效应,免疫荧光法分析血清中特异抗体水平和Vβ2^ T细胞数量。结果：pcDNA3．1-Vα．2或pcDNA3．1-Vβ2．1能在体内和体外真核细胞中转录,重组质粒免疫BALB／C小鼠能诱导产生特异性体液免疫应答、T细胞增殖反应及对靶细胞CTL反应,但pcDNA3．1-Vβ2．1免疫没有导致Vβ2^ T克隆清除,而是细胞活性部分封闭。结论：编码TcR Vα5．2或Vβ2．1的DNA免疫能诱导正常BALB/C小鼠调节性免疫应答。     

Immunological roles of intestinal mesenchymal cells

The intestine is continuously exposed to an enormous variety and quantity of antigens and innate immune stimuli derived from both pathogens and harmless materials, such as food and commensal bacteria. Accordingly, the intestinal immune system is uniquely adapted to ensure appropriate responses to the different kinds of challenge; maintaining tolerance to harmless antigens in the steady-state, whilst remaining poised to deal with potential pathogens. To accomplish this, leucocytes of the intestinal immune system have to adapt to a constantly changing environment and interact with many different non-leucocytic intestinal cell types, including epithelial and endothelial cells, neurons, and a heterogenous network of intestinal mesenchymal cells (iMC). These interactions are intricately involved in the generation of protective immunity, the elaboration of inflammatory responses, and the development of inflammatory conditions, such as inflammatory bowel diseases. Here we discuss recent insights into the immunological functions of iMC under homeostatic and inflammatory conditions, focusing particularly on iMC in the mucosa and submucosa, and highlighting how an appreciation of the immunology of iMC may help understand the pathogenesis and treatment of disease.     

Staphylococcus aureus strategies to evade the host acquired immune response

Staphylococcus aureus poses a significant public-health problem. Infection caused by S. aureus can manifest as acute or long-lasting persistent diseases that are often refractory to antibiotic and are associated with significant morbidity and mortality. To develop more effective strategies for preventing or treating these infections, it is crucial to understand why the immune response is incapable to eradicate the bacterium. When S. aureus first infect the host, there is a robust activation of the host innate immune responses. Generally, S. aureus can survive this initial interaction due to the expression of a wide array of virulence factors that interfere with the host innate immune defenses. After this initial interaction the acquired immune response is the arm of the host defenses that will try to clear the pathogen. However, S. aureus is capable of maintaining infection in the host even in the presence of a robust antigen-specific immune response. Thus, understanding the mechanisms underlying the ability of S. aureus to escape immune surveillance by the acquired immune response will help uncover potentially important targets for the development of immune-based adjunctive therapies and more efficient vaccines. There are several lines of evidence that lead us to believe that S. aureus can directly or indirectly disable the acquired immune response. This review will discuss the different immune evasion strategies used by S. aureus to modulate the different components of the acquired immune defenses.     

Echinococcus multilocularis proliferation in mice and respective parasite 14-3-3 gene expression is mainly controlled by an alphabeta CD4 T-cell-mediated immune response

The role of specific B lymphocytes and T-cell populations in the control of experimental Echinococus multilocularis infection was studied in micro MT, nude, T-cell receptor (TCR)-beta(-/-), major histocompatibility complex (MHC)-I(-/-) and MHC-II(-/-) mice. At 2 months postinfection, the parasite mass was more than 10 times higher in nude, TCR-beta(-/-) and MHC-II(-/-) mice than in infected C57BL/6 wild-type (WT) mice, and these T-cell-deficient mice started to die of the high parasite load at this time-point. In contrast, MHC-I(-/-) and micro MT mice exhibited parasite growth rates similar to those found in WT controls. These findings clearly point to the major role that CD4(+) alphabeta(+) T cells play in limiting the E. multilocularis proliferation, while CD8(+) T and B cells appeared to play a minor role in the control of parasite growth. In the absence of T cells, especially CD4(+) or alphabeta(+) T cells, the cellular immune response to infection was impaired, as documented by the lack of hepatic granuloma formation around the parasite and by a decreased splenocyte responsiveness to concanavalin A (Con A) and parasite antigen stimulation. Surprisingly, in T-cell-deficient mice, the ex vivo expression of interferon-gamma (IFN-gamma) and other inflammatory cytokines (except for interleukin-6) were increased in association with a high parasite load. Thus, the relative protection mediated by CD4(+) alphabeta(+) T cells against E. multilocularis infection seemed not be IFN-gamma dependent, but rather to rely on the effector's function of CD4(+) alphabeta(+) T cells. The local restriction of parasite germinal cell proliferation was reflected by a regulatory effect on the expression of 14-3-3 protein within the parasite tissue in T-cell-deficient mice. These results provide a strong indication that the CD4(+) alphabeta(+) T-cell-mediated immune response contributes to the control of the parasite growth and to the regulation of production of the parasite 14-3-3 protein in metacestode tissues.     

Gene expression profile analysis of epilepsy-associated gangliogliomas

Gangliogliomas (GG) constitute the most frequent tumor entity in young patients undergoing surgery for intractable epilepsy. The histological composition of GG, with the presence of dysplastic neurons, corroborates their maldevelopmental origin. However, their histogenesis, the pathogenetic relationship with other developmental lesions, and the molecular alterations underlying the epileptogenicity of these tumors remain largely unknown. We performed gene expression analysis using the Affymetrix Gene Chip System (U133 plus 2.0 array). We used GENMAPP and the Gene Ontology database to identify global trends in gene expression data. Our analysis has identified various interesting genes and processes that are differentially expressed in GG when compared with normal tissue. The immune and inflammatory responses were the most prominent processes expressed in GG. Several genes involved in the complement pathway displayed a high level of expression compared with control expression levels. Higher expression was also observed for genes involved in cell adhesion, extracellular matrix and proliferation processes. We observed differential expression of genes as cyclin D1 and cyclin-dependent kinases, essential for neuronal cell cycle regulation and differentiation. Synaptic transmission, including GABA receptor signaling was an under-expressed process compared with control tissue. These data provide some suggestions for the molecular pathogenesis of GG. Furthermore, they indicate possible targets that may be investigated in order to dissect the mechanisms of epileptogenesis and possibly counteract the epileptogenic process in these developmental lesions.     

Use of molecular typing to investigate bacterial translocation from the intestinal tract in malnourished children with Gram-negative bacteremia

Objective: To investigate whether translocation of intestinal Enterobacteriaceae was a likely source of bacteremia in children of 2 years or less hospitalized for fever and moderate malnutrition.
Methods: Blood and fecal cultures were obtained from 198 such children admitted in the Princess Basrna Hospital (Irbid, Jordan). Enterobacteriaceae isolated from blood cultures were compared with those present in fecal cultures by genomic typing using pulsed-field gel electrophoresis. The characteristics of children whose blood and fecal strain typing patterns were not distinguishable, i.e. with documented translocation, were compared to those of children without documented translocation.
Results: Bacterial translocation was documented in 12 of 19 children (63%) with Enterobacteriaceae bacterernia for whom paired blood and fecal strains were available for genomic typing, and was thus the major source of these bacteremias. The clinical or biological signs of malnutrition were not significantly more pronounced in the bacteremic children with documented translocation than in those without.
Conclusions: We demonstrated that bacterial translocation from the intestinal tract was the most common source of Gram-negative bacteremia in the population studied.     

表达谱芯片筛查非小细胞肺癌细胞系A549放疗抵抗差异基因

目的 建立非小细胞肺癌（NSCLC）A549放疗抵抗模型,表达谱芯片技术筛查放疗抵抗差异基因。 方法 A549细胞系长期间歇照射诱导建立的放疗抵抗细胞模型;表达谱基因芯片筛查放疗抵抗细胞株与敏感株全基因组RNA表达差异;分析2倍以上差异的基因（P<0.05）,分别进行生物学信息基因分类(GO)和信息通路（Pathway）分析。 结果 表达谱芯片显示,抵抗株与敏感株相比,差异表达基因为1410个（733个上调,677个下调）;GO分析显示,主要与细胞周期、DNA修复有关;通路显著性富集分析显示,丝裂原活化蛋白激酶（MAPK）和磷脂酰肌醇-3-激酶（PI3K）等多条信号通路激酶出现显著性差异。 结论 多种基因和信号通路参与了放疗抵抗过程。     

免疫应答类型的重新分类

过渡性免疫应答由原属固有免疫应答的原始B1细胞、γδT细胞和NKT细胞所组成.其中原始B1细胞承担过渡性免疫应答的体液免疫,γδT细胞和NKT细胞承担过渡性免疫应答的细胞免疫,主要识别和排除TI抗原.固有免疫应答的细胞包括吞噬细胞、树突状细胞、NK细胞等,体液免疫组包括补体、急性期蛋白、溶菌酶等,其主要作用是非特异性地清除或递呈抗原.适应性免疫应答的细胞由B2细胞和αβT细胞组成,B2细胞承担适应性体液免疫应答,αβT细胞承担适应性细胞免疫应答,主要识别和排除胸腺依赖性抗原(TD).免疫应答分为3种类型是对免疫系统进化的客观阐述,符合物种进化的基本规律,准确反映了免疫功能的发生和发展,对完善免疫学基础理论以及指导临床免疫学研究具有重要的意义.