How the insect immune system interacts with an obligate symbiotic bacterium

The animal immune system provides defence against microbial infection, and the evolution of certain animal–microbial symbioses is predicted to involve adaptive changes in the host immune system to accommodate the microbial partner. For example, the reduced humoral immune system in the pea aphid Acyrthosiphon pisum, including an apparently non-functional immune deficiency (IMD) signalling pathway and absence of peptidoglycan recognition proteins (PGRPs), has been suggested to be an adaptation for the symbiosis with the bacterium Buchnera aphidicola. To investigate this hypothesis, the interaction between Buchnera and non-host cells, specifically cultured Drosophila S2 cells, was investigated. Microarray analysis of the gene expression pattern in S2 cells indicated that Buchnera triggered an immune response, including upregulated expression of genes for antimicrobial peptides via the IMD pathway with the PGRP-LC as receptor. Buchnera cells were readily taken up by S2 cells, but were subsequently eliminated over 1–2 days. These data suggest that Buchnera induces in non-host cells a defensive immune response that is deficient in its host. They support the proposed contribution of the Buchnera symbiosis to the evolution of the apparently reduced immune function in the aphid host.     

Review of Glycosylation Engineering of Biopharmaceuticals: Methods and Protocols

The glycoform profile of a glycoprotein is non-templated, i.e., is not encoded within the genome or otherwise predetermined; however, it is estimated that ~50% of human genes having an open reading frame encode a –N-X-S/T- amino acid sequence, where X represents any amino acid other than proline, that comprises a potential site (sequon) for N-linked glycosylation of the translated protein. N-linked glycosylation is both a co- and post-translational modification. The complex oligosaccharide GlcNAc2Man9Glu3 may be added at a –N-X-S/T- sequon as the polypeptide chain emerges from the ribosome tunnel. Local secondary structure determines whether oligosaccharide is added and the extent of addition. Higher occupancy is observed for –N-X-T- sequons than at –N-X-S- sequons, and the efficiency of addition can be further influenced by adjacent amino acid residues.     

中华硬蜱和二棘血蜱的交叉免疫反应

本文首次比较了经中华硬蜱(Ixodes sinensis)叮咬三次后再经二棘血蜱(Haemaphysalisbispinosa)叮咬的家兔与仅经二棘血蜱叮咬的家兔的交叉免疫抗性。二棘血蜱叮咬被中华硬蜱致敏的家兔时,吸血增重为:143.12±32.67mg,但二棘血蜱在正常家兔体上寄生,初次吸血增重为:181.30±44.35mg,两者之间有显著性差异(P<0.01)。中华硬蜱和二棘血蜱唾液腺提取物(SGE)经十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE),显示两者分别有24条和22条电泳带,中华硬蜱主带有6条,分子量分别为142、105、94、66/65、64和56kD,而二棘血蜱主带有5条,分子量分别为:215、114、105、66/65和58kD,经中华硬蜱叮咬致敏的家兔血清和经二棘血蜱叮咬致敏的家兔血清作免疫印渍,均显示出105kD这一电泳带。该实验表明中华硬蜱和二棘血蜱叮咬家兔两者之间存在着交叉免疫反应,提示105kD蛋白质抗原可能是两者的共同抗原。     

Sex differences in circulating antibodies in nestling Pied Flycatchers Ficedula hypoleuca

Sex differences in immune function are relatively well studied in vertebrate animals, although the patterns are not always clear in birds. The study of immune responses in nestlings of wild bird populations may constitute an appropriate way to investigate inherent intersexual differences while controlling for environmental conditions such as parasitism that affect male and female individuals growing in the same nest. We studied whether the cell‐mediated immune response, as measured by phytohaemagglutinin (PHA) injection, and the levels of circulating antibodies differ between sexes of Pied Flycatcher nestlings Ficedula hypoleuca. No sex differences in nestling cell‐mediated immune response were found, but females showed significantly higher levels of plasma immunoglobulins than males did. Although nestling birds may not have a fully functional humoral immune defence, our study indicates that sex differences in the humoral component exist at this early stage of life. Given the importance of antibodies in the fight against parasite, bacterial and viral infections, the intrinsic sex disparity in circulating antibodies may have important implications for the life history of each sex.     

Gene therapy: light is finally in the tunnel

After two decades of ups and downs, gene therapy has recently achieved a milestone in treating patients with Leber’s congenital amaurosis (LCA). LCA is a group of inherited blinding diseases with retinal degeneration and severe vision loss in early infancy. Mutations in several genes, including RPE65, cause the disease. Using adeno-associated virus as a vector, three independent teams of investigators have recently shown that RPE65 can be delivered to retinal pigment epithelial cells of LCA patients by subretinal injections resulting in clinical benefits without side effects. However, considering the whole field of gene therapy, there are still major obstacles to clinical applications for other diseases. These obstacles include innate and immune barriers to vector delivery, toxicity of vectors and the lack of sustained therapeutic gene expression. Therefore, new strategies are needed to overcome these hurdles for achieving safe and effective gene therapy. In this article, we shall review the major advancements over the past two decades and, using lung gene therapy as an example, discuss the current obstacles and possible solutions to provide a roadmap for future gene therapy research.     

ERKs activation and calcium signaling are both required for VEGF induction by vanadium in mouse epidermal Cl41 cells

Studies were conducted to determine the immunomodulatory effects of high dietary ascorbic acid (vitamin C) on growth, serum concentration, non-specific immune response and disease resistance of a commercially important Asian catfish, Clarias batrachus. Four practical diets were formulated to contain 0, 500, 1000 and 2000 mg ascorbic acid (AA) equivalent/kg diet, supplied as L-ascorbyl-2-polyphosphate (LAPP) and were fed for 2, 4, 6 and 8 weeks. Each diet was fed to triplicate groups of catfish with initial body weight of 15.47± 0.59 g. After 2, 4, 6 and 8 weeks, growth, serum concentration of AA, oxidative respiratory burst, lysozyme and natural hemolytic complement activities, myeloperoxidase (MPO) content and natural haemagglutination titre were measured. Ten numbers of fish in duplicate were challenged with Aeromonas hydrophila to measure the level of protection against aeromoniasis at each one of the assayed times. The results showed that AA concentration in serum correlated positively with those in the diets and reached its saturation level after the time period directly proportional to the increase in dose level. Fish fed AA-supplemented diets showed significantly (p < 0.05) higher specific growth rate after 2 weeks of feeding. The superoxide production was enhanced after 8 weeks of feeding fish at a supplemented dose level of 2000 mg/kg. Similarly, MPO content, haemagglutination titre and alternative complement activity in serum enhanced with the increase of dietary AA levels at different duration of feeding. The lysozyme activity was not affected by the dietary AA treatment. On the other hand, feeding of AA at all concentrations significantly increased percent survival against A. hydrophila challenge after 4 weeks compared to control. The non-specific immune parameters as well as percent survival were enhanced as a result of high AA supply particularly at 500 mg/kg diet, although the increase was not maintained but returned to the initial levels after 4 weeks. These results support the possible use of AA as an immunostimulant at a dose of 500 mg/kg diet for a period of 4 weeks in catfish farming. (Mol Cell Biochem xxx: 25–33, 2005)     

烟草甲clip丝氨酸蛋白酶基因的克隆及其对外源激素和免疫胁迫的表达响应(英文)

【目的】作为细胞外信号级联通路的重要组成部分,含有clip结构域的丝氨酸蛋白酶(clip-domain serine proteases, CLIPs)在昆虫发育和先天免疫过程中起着重要作用。本研究旨在克隆烟草甲Lasioderma serricorne CLIP基因,解析其在烟草甲不同发育阶段和幼虫不同组织中的表达模式,分析其在外源激素20-羟基蜕皮酮(20E)和免疫胁迫后的表达特征,为进一步研究其生理功能奠定基础。【方法】采用RT-PCR技术克隆获得烟草甲两个CLIPs基因(LsCLIP1和LsCLIP2)全长cDNA序列,并利用生物信息学软件预测其编码蛋白的结构和特征,利用MEGA 6.06构建昆虫CLIPs系统发育树;利用实时荧光定量PCR(quantitative real-time PCR, qPCR)研究这两个基因在不同发育阶段［低龄幼虫(卵孵化后24 h内)、高龄幼虫(4龄以上)、蛹(化蛹后48 h以上)、早期成虫(化蛹后24 h内)和晚期成虫(化蛹后7 d)］、5龄幼虫不同组织(表皮、脂肪体、肠道和剩余组织)中以及注射20E(120 ng/幼虫)和来源于大肠杆菌Escherichia coli和金黄色葡萄球菌Staphylococcus aureus的肽聚糖(0.2 μL)后4龄幼虫中的表达模式。【结果】克隆获得烟草甲LsCLIP1和LsCLIP2基因的cDNA全序列,其开放阅读框长度均为1 194 bp,编码397个氨基酸。序列分析显示,其氨基酸序列各自具有一个clip结构域和胰蛋白酶结构域。系统发育分析表明,CLIP1和CLIP2都属于subfamily C CLIPs。qPCR结果表明,LsCLIP1和LsCLIP2基因在所检测的各发育阶段和幼虫各组织中均有表达,分别尤以蛹期和表皮中表达量最高;经20E和肽聚糖诱导后,烟草甲幼虫体内LsCLIP1和LsCLIP2基因的表达量明显提高。【结论】推测LsCLIP1和LsCLIP2可能参与了烟草甲的蜕皮发育和对免疫胁迫的应激响应。本研究将为后续研究昆虫CLIPs的分子调控提供参考。     

Effects of dexamethasone and FK506 on Helicobacter pylori-induced gastritis and bacterial viability in Mongolian gerbils

FK506 and dexamethasone were used to investigate whether or not immunosuppression affects H. pylori colonization and gastric mucosal damage induced by Helicobacter pylori in Mongolian gerbils. Two weeks after H. pylori infection, FK506 and dexamethasone or vehicle alone were subcutaneously administered once daily for the following 2 weeks. FK506 or vehicle alone was administered subcutaneously once daily for 5 weeks (1 week before and 4 weeks after infection). In H. pylori-infected animals for 4 weeks, hemorrhagic erosions and inflammatory responses (neutrophil infiltration and lymphoid follicle formation) were induced in gastric mucosa at an incidence of 100%. Both FK506 and dexamethasone administered for 2 weeks markedly reduced such mucosal changes. In these animals, H. pylori viability in the stomach was significantly elevated. FK506 administered for 5 weeks also significantly inhibited the hemorrhagic erosions, edema and neutrophil infiltration in the stomach. H. pylori viability was slightly elevated as compared with the control. It was concluded that the host immune responses might play dual roles both by deteriorating gastritis induced by H. pylori and by protecting against H. pylori infection in its early stage.