Increased interleukin-17 producing effector memory T cells in the end-stage renal disease patients

Patients with end-stage renal disease (ESRD) exhibit immune dysregulation, but the precise immunological profile and the effect of hemodialysis (HD) on it has not been investigated fully. Thirty-eight ESRD patients (22 on HD and 16 in pre-dialysis) and 24 healthy volunteers were included. We compared the T cell immune profiles as in these patients. Among the effector T cell subset, the percentages of Th17 and Th2 cells were significantly higher in the ESRD group than in the healthy controls (P<0.05). The percentage of Th1 cells did not differ significantly between these groups. The percentages of Th1, Th2 and Th17 cells did not differ significantly (P>0.05) between the two subgroups within the ESRD group. The CCR4(-)CCR6(+)/CD4(+) T cell percentage was also significantly higher in the ESRD group. The na?ve T cell (T(na?ve)) percentage was significantly lower in the ESRD group, and the difference between patients and controls was greater in the pre-dialysis patients than in the HD patients (P<0.05, for each comparison). By contrast, the percentages of central memory T cells (T(CM)) and effector memory T (T(EM)) cells were significantly higher in the ESRD group. Interleukin-17 production by T(EM) cells was significantly higher in the ESRD group. The severity of uremia was related negatively to the T(na?ve) cell percentage but positively to the T(CM) and T(EM) cell percentages. The percentages of T(EM) and CD45RA(+) T effector memory subsets of CD8(+) T cells were significantly higher in the ESRD group (P<0.05). The result of this study showed significantly altered T cell-associated immunity and that it could not be corrected with hemodialysis.     

T cell responses induced by allergen-specific immunotherapy

Allergen‐specific immunotherapy is recognized as a highly effective practice in the treatment of patients with severe allergic rhinitis and/or asthma and is recommended by World Health Organization as an integrated part of allergy management strategy. Several studies have shown that allergen‐specific immunotherapy, based on the administration of increasing doses of allergen, achieves a hyposensitization and reduces both early and late responses occurring during the natural exposure to the allergen itself. This is the unique antigen‐specific immunomodulatory treatment in current use for human diseases. Successful immunotherapy is associated with reductions in symptoms and medication scores and improved quality of life. After interruption it usually confers long‐term remission of symptoms and prevents the onset of new sensitizations in children up to a number of years. Subcutaneous immunotherapy usually suppresses the allergen‐induced late response in target organs, likely due to the reduction of the infiltration of T cells, eosinophils, basophils, mast cells and neutrophils. In addition to the reduction of cells of allergic inflammation, immunotherapy also decreases inflammatory mediators at the site of allergen exposure. This review provides an update on the immunological T cell responses induced by conventional subcutaneous and sublingual immunotherapy, and gives a unifying view to reconciling the old dualism between immunoredirecting and immunoregulating mechanisms.     

A functional role of flip in conferring resistance of Crohn's disease lamina propria lymphocytes to FAS-mediated apoptosis

BACKGROUND & AIMS: There is evidence that, in Crohn's disease (CD), lamina propria T lymphocytes (LPLs) are resistant to FAS-mediated apoptosis and that this defect contributes to the mucosal T-cell accumulation. In this study we examined the functional role of Flip, a Flice inhibitor protein, in the resistance of CD LPL to FAS-mediated apoptosis. METHODS: Biopsy specimens and LPLs were taken from CD and ulcerative colitis (UC) patients and normal controls and analyzed for Flip by Western blotting. We also examined whether inhibition of Flip by antisense oligonucleotide restored the susceptibility of CD LPLs to FAS-induced apoptosis. LPL apoptosis was assessed by flow cytometry. RESULTS: After FAS stimulation, the rate of apoptosis of CD3+ LPLs was higher in normal controls and patients with UC than in patients with CD. Enhanced expression of both long and short Flip isoforms was seen in biopsy specimens and purified CD3+ and CD45RO+ LPLs of CD patients in comparison with UC patients and normal controls. No increase in Flip was documented in untreated celiac disease mucosa, thus suggesting the possibility that induction of Flip in the gut does not simply rely on the ongoing inflammation. Finally, we showed that inhibition of Flip by antisense oligonucleotide reverted the resistance of CD LPLs to FAS-induced apoptosis. CONCLUSIONS: Data suggest a role for Flip in the resistance of CD LPLs to FAS-mediated apoptosis.     

Agonistic antibodies to human glucocorticoid-induced tumor necrosis factor receptor as potential stimulators of T cell immunity for the treatment of cancer and viral infections

The magnitude of adaptive T cell responses is controlled by costimulatory molecules, including cell-surface associated members of the tumor necrosis factor receptor (TNF-R) family that modulate T cell receptor (TCR)-dependent activation, and by a network of regulatory T (Treg) cells that downregulate effector T cell functions. The glucocorticoid-induced TNF-R (GITR) is a type I transmembrane protein that is expressed at high levels on CD4⁺ CD25⁺ Treg cells and on activated effector T cells. In vitro studies have shown that ligation of GITR with an agonistic monoclonal antibody (mAb) could abrogate the suppressive activity of Treg cells and enhance the survival, proliferation and effector functions of TCR-activated CD4⁺ and CD8⁺ T cells. Furthermore, studies in mice demonstrated that mAb-triggered GITR stimulation could also markedly augment antitumor and virus-specific T cell responses in vivo. This has suggested that agonistic anti-GITR mAbs may serve to stimulate T cell immunity for therapeutic purposes. Accordingly, the present patent application reports the generation of a novel agonistic murine mAb to human GITR that is able to reverse Treg-mediated suppression and costimulate T cell activation in vitro. Humanized versions of the mAb are also described, but without providing data on their binding and functional properties. Further studies will be needed to fully appraise the potential utility of these human mAbs for the immunotherapy of cancer or viral infections.     

膏摩法结合超声药物透入治疗颈源性肩背痛的疗效观察

目的 观察膏摩法结合超声药物透入治疗颈源性肩背痛的疗效及相关效应因子的调节变化。方法 随机将符合要求的96例颈源性肩背痛患者分为两组,治疗组48例,对照组48例。治疗组以膏摩手法结合超声药物透入疗法,对照组采用常规手法结合口服塞来昔布胶囊的方法。分别观察两组治疗前后的疗效及相关效应(炎性)因子白细胞介素-1β受体拮抗剂、白细胞介素-6及肿瘤坏死因子的浓度变化,并参照标准进行临床疗效的评定。结果 两组的炎性因子浓度变化方面:治疗后血清白细胞介素-1β受体拮抗剂浓度均增加,治疗组增加程度大于对照组(t=4.157,P=0.0001),两组血清白细胞介素-6浓度均有降低,治疗组降低程度大于对照组(t=8.739,P=0.0001),两组血清肿瘤坏死因子浓度均有降低,治疗组降低程度大于对照组(t=2.727,P=0.0076);临床疗效方面：治疗组总有效率91.7%,对照组总有效率75.0%,疗效优于对照组(F=0.026)。结论 膏摩法结合超声药物透入治疗颈源性肩背痛的疗效优于常规手法及服药,能调节血清中白细胞介素-1β受体拮抗剂、白细胞介素-6和肿瘤坏死因子等的浓度,是治疗颈源性肩背痛较为有效的方法。     

Protein array analysis of oligomerization-induced changes in alpha-synuclein protein-protein interactions points to an interference with Cdc42 effector proteins

Aggregation of alpha-synuclein may contribute to neuropathology in Parkinson's disease patients and in transgenic animal models. Natively unfolded alpha-synuclein binds to various proteins and conformational changes due to alpha-synuclein misfolding may alter physiological interactions. In the present study, we used protein arrays spotted with 5000 recombinant human proteins for a large scale interaction analysis of monomeric versus oligomeric alpha-synuclein. Monomeric alpha-synuclein bound to arrayed cAMP regulated phosphoprotein 19 and binding appears to be disrupted by alpha-synuclein oligomerization. Incubation with recombinant alpha-synuclein oligomers lead to the identification of several GTPase activating proteins and Cdc42 effector proteins as binding partners. Protein database searches revealed a Cdc42/Rac interactive binding domain in some interactors. To demonstrate in vivo relevance, we analyzed brainstem protein extracts from alpha-synuclein(A30P) transgenic mice. Pull-down assays using beads conjugated with a Cdc42/Rac interactive binding domain lead to an enrichment of endogenous alpha-synuclein oligomers. Cdc42 effector proteins were also co-immunoprecipitated with alpha-synuclein from brainstem lysates and were colocalized with alpha-synuclein aggregates in brain sections by double immunostaining. By two-dimensional gel electrophoretic analysis of synaptosomal fractions from transgenic mouse brains we detected additional isoforms of septin 6, a downstream target of Cdc42 effector proteins. Small GTPases have recently been identified in a genetic modifier screen to suppress alpha-synuclein toxicity in yeast. Our data indicate that components of small GTPase signal transduction pathways may be directly targeted by alpha-synuclein oligomers which potentially leads to signaling deficits and neurodegeneration.     

细菌Ⅳ型分泌系统的研究进展

革兰阴性细菌的分泌系统有Ⅰ~Ⅵ型,其中Ⅳ型分泌系统(Type Ⅳ Secretion System,T4SS)不但可以介导DNA的水平转移,还可以转运蛋白质及核糖核蛋白复合物等大分子物质。T4SS通过介导抗性基因或毒力基因水平转移有利于细菌进化或直接将效应蛋白分子转运至宿主细胞,参与细菌致病。本文除介绍T4SS的类型、结构、生物学功能等方面的研究进展外,还介绍了基于蛋白相互作用及生物信息学方法的T4SS分泌效应蛋白的识别方法。     

Functional prokaryotic-eukaryotic chimera from the pentameric ligand-gated ion channel family

Pentameric ligand-gated ion channels (pLGICs), which mediate chemo-electric signal transduction in animals, have been recently found in bacteria. Despite clear sequence and 3D structure homology, the phylogenetic distance between prokaryotic and eukaryotic homologs suggests significant structural divergences, especially at the interface between the extracellular (ECD) and the transmembrane (TMD) domains. To challenge this possibility, we constructed a chimera in which the ECD of the bacterial protein GLIC is fused to the TMD of the human α1 glycine receptor (α1GlyR). Electrophysiology in Xenopus oocytes shows that it functions as a proton-gated ion channel, thereby locating the proton activation site(s) of GLIC in its ECD. Patch-clamp experiments in BHK cells show that the ion channel displays an anionic selectivity with a unitary conductance identical to that of the α1GlyR. In addition, pharmacological investigations result in transmembrane allosteric modulation similar to the one observed on α1GlyR. Indeed, the clinically active drugs propofol, four volatile general anesthetics, alcohols, and ivermectin all potentiate the chimera while they inhibit GLIC. Collectively, this work shows the compatibility between GLIC and α1GlyR domains and points to conservation of the ion channel and transmembrane allosteric regulatory sites in the chimera. This provides evidence that GLIC and α1GlyR share a highly homologous 3D structure. GLIC is thus a relevant model of eukaryotic pLGICs, at least from the anionic type. In addition, the chimera is a good candidate for mass production in Escherichia coli, opening the way for investigations of "druggable" eukaryotic allosteric sites by X-ray crystallography.     

Translocation of surface-localized effectors in type III secretion

Pathogenic Yersinia species suppress the host immune response by using a plasmid-encoded type III secretion system (T3SS) to translocate virulence proteins into the cytosol of the target cells. T3SS-dependent protein translocation is believed to occur in one step from the bacterial cytosol to the target-cell cytoplasm through a conduit created by the T3SS upon target cell contact. Here, we report that T3SS substrates on the surface of Yersinia pseudotuberculosis are translocated into target cells. Upon host cell contact, purified YopH coated on Y. pseudotuberculosis was specifically and rapidly translocated across the target-cell membrane, which led to a physiological response in the infected cell. In addition, translocation of externally added YopH required a functional T3SS and a specific translocation domain in the effector protein. Efficient, T3SS-dependent translocation of purified YopH added in vitro was also observed when using coated Salmonella typhimurium strains, which implies that T3SS-mediated translocation of extracellular effector proteins is conserved among T3SS-dependent pathogens. Our results demonstrate that polarized T3SS-dependent translocation of proteins can be achieved through an intermediate extracellular step that can be reconstituted in vitro. These results indicate that translocation can occur by a different mechanism from the assumed single-step conduit model.