靶向M细胞的抗原递送¾¾增强黏膜免疫应答的关键策略

黏膜是阻止病原入侵的第一道防线,黏膜免疫系统在抵抗感染方面起着至关重要的作用。通过黏膜途径接种疫苗可以同时诱导黏膜和全身免疫反应,因此,理论上针对黏膜的免疫策略是最合理和有效的。但黏膜免疫系统的复杂性和屏障作用造成抗原诱导的免疫应答水平低下,制约了黏膜疫苗的发展。M细胞(Microfoldcells)是黏膜免疫系统所独有的,其具有捕获腔内抗原和启动抗原特异性免疫应答的功能。M细胞摄取抗原的多少直接关系到黏膜疫苗的免疫效力,而利用M细胞配体可将抗原靶向递呈给M细胞,从而实现高效的黏膜免疫应答。靶向M细胞的抗原递送策略及其应用可以提高黏膜免疫应答水平,促进黏膜疫苗的研制。尽管如此,要成功研制安全高效的黏膜疫苗,今后依然有漫长的路要走,这可能有赖于进一步探究M细胞的特性和功能及黏膜免疫机制。     

TGF‐β1 improves mucosal IgA dysfunction and dysbiosis following intestinal ischaemia–reperfusion in mice

Intestinal ischaemia/reperfusion (I/R) severely disrupts gut barriers and leads to high mortality in the critical care setting. Transforming growth factor (TGF)‐β1 plays a pivotal role in intestinal cellular and immune regulation. However, the effects of TGF‐β1 on intestinal I/R injury remain unclear. Thus, we aimed to investigate the effects of TGF‐β1 on gut barriers after intestinal I/R and the molecular mechanisms. Intestinal I/R model was produced in mice by clamping the superior mesenteric artery for 1 hr followed by reperfusion. Recombinant TGF‐β1 was intravenously infused at 15 min. before ischaemia. The results showed that within 2 hrs after reperfusion, intestinal I/R disturbed intestinal immunoglobulin A class switch recombination (IgA CSR), the key process of mucosal IgA synthesis, and resulted in IgA dysfunction, as evidenced by decreased production and bacteria‐binding capacity of IgA. Meanwhile, the disruptions of intestinal microflora and mucosal structure were exhibited. Transforming growth factor‐β1 activated IgA CSR as evidenced by the increased activation molecules and IgA precursors. Strikingly, TGF‐β1 improved intestinal mucosal IgA dysfunction, dysbiosis and epithelial damage at the early stage after reperfusion. In addition, SB‐431542, a specific inhibitor of activating mothers against decapentaplegic homologue (SMAD) 2/3, totally blocked the inductive effect of TGF‐β1 on IgA CSR and almost abrogated the above protective effects on intestinal barriers. Taken together, our study demonstrates that TGF‐β1 protects intestinal mucosal IgA immunity, microbiota and epithelial integrity against I/R injury mainly through TGF‐β receptor 1/SMAD 2/3 pathway. Induction of IgA CSR may be involved in the protection conferred by TGF‐β1.     

Effect of peripherally-injected glucagon-like peptide-1 on gastric mucosal blood flow

The aim of this study was to investigate the mechanisms involved in the effect of glucagon-like peptide-1 (GLP-1) on the decrease in gastric mucosal blood flow (GMBF) induced by intragastric ethanol.After preparation of the stomach for GMBF recording, a probe was placed to the gastric mucosa and basal GMBF recordings were obtained by a laser Doppler flowmeter after a 30-minute stabilization period. Following GLP-1 (1000 ng/kg; i.p.) injection, 1 ml of absolute ethanol was applied to the gastric chamber and GMBF was recorded continuously during a 30-minute period. GLP-1 (1000 ng/kg; i.p.) prevented the decrease in GMBF induced by ethanol. Nitric oxide (NO) synthase inhibitor L-NAME, (30 mg/kg; s.c.), calcitonine gene-related peptide (CGRP) receptor antagonist CGRP-(8–37) (10μg/kg; i.p.), and cyclooxygenase inhibitor indomethacin (5 mg/kg; i.p.) all inhibited the GMBF-improving effect of GLP-1.We concluded that, NO, CGRP and prostaglandins may be involved in the effect of peripherally-injected GLP-1 on GMBF reduction induced by intraluminal ethanol.     

Magnetic resonance imaging in vivo monitoring of T2 relaxation time: Quantitative assessment of primate brain maturation

This work describes quantitative MRI assessment of primate brain maturation. Nine young baboons were followed from the age of one to 30 months. Assessment of myelination was based on the gray/white matter contrast on MR images and the evolution of T2 relaxation time respectively. The brain maturation began in the posterior fossa and progressed to the olfactory bulbs corresponding to decreasing white matter T2 values. Relaxation parameters provide new opportunities to trace the myelination process in vivo.     

Tumor necrosis factor-alpha in serum of macaques during SIVmac251 acute infection

TNF secretion was explored in sera during acute SIV-infection of cynomolgus macaques. A peak of TNF was detected in sera of animals in concomitance with SIV replication. Likewise, AZT treatment delayed and reduced peaks of viral replication and TNF production. Thus, SIVmac251-infected monkey could be an excellent model to explore the interdigitation existing between HIV and TNF in acute and chronic infection and to develop new therapeutic strategies that target the production of this cytokine or its inductive effects.     

MHC expression of African green monkeys of Barbados is limited in heterogeneity

Major histocompatibility complex expression of activated peripheral blood lymphocytes of captive African green monkeys from Barbados and from Africa were analyzed biochemically; class I molecules by one-dimensional isoelectric focusing and class II DR molecules by one-dimensional nonequilibrium pH gradient electrophoresis. Much less diversity was observed in the major histocompatability molecule expression of the African green monkeys of Barbados than in the African cohort.     

活菌疫苗载体的研究与应用

目前在疫苗研究中,要求新型疫苗不仅能够激发高效持久的免疫应答,而且应易于接种、生产费用低。减毒或无毒的活微生物作为疫苗载体能够激起持久的系统和黏膜免疫反应,批量制备成本较低,且具有良好的安全性,近年来已成为疫苗研究领域的热点。本文综述了几种活菌疫苗载体,包括沙门氏菌、卡介苗、耶尔森菌等的研究状况及其在疫苗载体方面的应用。     

Generation of monoclonal antibodies to Macaca mulatta (rhesus) IgA

One IgG1 and five IgM murine monoclonal antibodies (mAb) specific for rhesus (Rh) IgA were generated. These mAbs bound to Rh IgA but not IgG or IgM when tested by enzyme-linked immunosorbent assay. Immunoblotting revealed that the mAbs reacted with the alpha heavy chain of Rh but not human IgA. The IgG1 anti-Rh IgA mAb detected IgA-producing cells in sections of monkey gut examined by immunofluorescent staining. These mAbs should be useful for characterizing IgA responses in the Rh monkey.     

Frequent detection of HIV-1 RNA but low rates of HIV-1 isolation in cervicovaginal secretions from infected women

Information regarding the presence of HIV-1 in the female genital tract is necessary to gain insight into the mechanism of HIV-1 heterosexual transmission. Herein, we present the results of a study on virus isolation and HIV-1 RNA detection from cervicovaginal lavage (CVL) samples from 25 HIV-1 seropositive women. Despite detectable levels of HIV-1 RNA in 88% of CVL samples, HIV-1 was isolated in only four (19%) samples. Although HIV-1 shedding in cervicovaginal secretions is a common event at all disease stages, the recovery of infectious virus in cell cultures appears to be rare; this renders viral isolation in studies aimed to evaluate the infectivity of cervicovaginal secretions relatively useless.     

参麦注射液对严重烫伤大鼠肠道屏障功能的保护作用

目的:探索参麦注射液对30% Ⅲ°烫伤早期肠道屏障功能的保护作用,为参麦注射液防治肠源性感染提供实验依据。方法:Wistar大鼠60只,随机分为正常对照组、模型对照组,地塞米松5 mg/kg组、参麦注射液5、10、15 mg/kg组,每组10只,使用烫伤仪建立30% Ⅲ°烫伤动物模型,立即腹腔注射相应的药物,每天1次。烫伤72 h后,检测肝脏、脾脏、肠系膜淋巴结细菌移位量、血浆内毒素、二胺氧化酶(DAO)、肿瘤坏死因子-α(TNF-α)及白细胞介素-6(IL-6)水平和肠粘膜分泌型免疫球蛋白A(sIgA)的水平。结果:与正常对照组比较,模型组肝脏、脾脏、肠系膜淋巴结细菌移位量,血浆内毒素、DAO、TNF-α及 IL-6和肠黏膜sIgA水平明显升高(P＜0.01);与模型组比较,地塞米松组和参麦注射液5、10、15 mg/kg组肝脏、脾脏、肠系膜淋巴结细菌移位量,血浆内毒素、DAO、TNF-α及 IL-6和肠黏膜sIgA水平明显降低(P＜0.05或P＜0.01)。结论:参麦注射液可减轻严重烫伤引起的肠粘膜损伤,效果与地塞米松相当,高剂量组效果更好。     

人体黏膜活组织模型在HIV-1 性传播途径感染中的应用

性传播途径已经成为全球人免疫缺陷病毒1型 (Human immunodeficiency virus type 1,HIV-1) 传播的主要方式。对HIV-1黏膜感染机制的深入理解,将有助于研发新型有效的生物技术阻断其感染和传播。目前,HIV-1黏膜感染机制的研究主要依赖于体外细胞培养和灵长类动物模型。近年来,一种新型黏膜活组织模型 (包括人体生殖道或肠道黏膜等组织) 的建立,可再现HIV-1突破黏膜屏障进入基底侧的生物学过程,适用于HIV-1黏膜感染机制与黏膜局部感染阻断生物技术的临床前有效性评价研究。     

M细胞在肠黏膜免疫中作用的研究进展

M细胞是肠道一种免疫细胞,同时,也是一种特殊的抗原运转细胞。M细胞具有特殊的形态结构特点,与肠黏膜免疫功能密切相关。目前认为,位于肠淋巴滤泡上皮中特化的M细胞是大多数黏膜病原体侵入机体的靶细胞,它能特异性的结合肠道大分子物质及微生物,并将其摄取、转运至位于其下的APC进行识别、处理,并激活T、B淋巴细胞,继而激发肠道黏膜免疫应答作用。本研究就目前国内外学者所做M细胞在肠黏膜免疫中作用的研究进展做一综述。     

Development of broadly neutralizing antibodies in HIV-1 infected elite neutralizers

Broadly neutralizing antibodies (bNAbs), able to prevent viral entry by diverse global viruses, are a major focus of HIV vaccine design, with data from animal studies confirming their ability to prevent HIV infection. However, traditional vaccine approaches have failed to elicit these types of antibodies. During chronic HIV infection, a subset of individuals develops bNAbs, some of which are extremely broad and potent. This review describes the immunological and virological factors leading to the development of bNAbs in such “elite neutralizers”. The features, targets and developmental pathways of bNAbs from their precursors have been defined through extraordinarily detailed within-donor studies. These have enabled the identification of epitope-specific commonalities in bNAb precursors, their intermediates and Env escape patterns, providing a template for vaccine discovery. The unusual features of bNAbs, such as high levels of somatic hypermutation, and precursors with unusually short or long antigen-binding loops, present significant challenges in vaccine design. However, the use of new technologies has led to the isolation of more than 200 bNAbs, including some with genetic profiles more representative of the normal immunoglobulin repertoire, suggesting alternate and shorter pathways to breadth. The insights from these studies have been harnessed for the development of optimized immunogens, novel vaccine regimens and improved delivery schedules, which are providing encouraging data that an HIV vaccine may soon be a realistic possibility.     

不同黏膜佐剂对猪丁型冠状病毒诱导小鼠免疫应答的影响

【目的】旨在为猪丁型冠状病毒(porcine deltacoronavirus,PDCoV)灭活疫苗黏膜免疫筛选理想佐剂,降低疫苗副作用。利用小鼠模型评价不同佐剂制备的PDCoV灭活疫苗对体液免疫、细胞免疫和黏膜免疫应答的影响。【方法】将甘露聚糖肽(PA)、CpGODN2395、单磷酰脂质A(MPLA)佐剂分别与IMS 1313、GEL02佐剂联合制备PDCoV灭活疫苗,经鼻腔免疫BALB/c小鼠;将ISA201佐剂制备的PDCoV灭活疫苗经皮下免疫BALB/c小鼠,将PDCoV灭活抗原经鼻腔免疫BALB/c小鼠作为对照,间隔14 d加强免疫一次。用ELISA方法检测小鼠血清、支气管肺泡灌洗液(BALF)中的IgG、IgG1、IgG2a、IL-4、IFN-γ及粪便和BALF中sIgA表达水平;用MTT方法检测疫苗免疫后对小鼠脾淋巴细胞增殖的影响;观察并记录小鼠免疫后的临床表现,HE染色方法观察免疫小鼠主要器官组织的病理学变化,评价疫苗的安全性。【结果】ISA201组小鼠BALF和血清中的抗体(IgG、IgG1)及IL-4表达水平相对较高,但IgG2a、IFN-γ和粪便中sIgA表达水平...     

Helicobacter pylori modulation of gastric and duodenal mucosal T cell cytokine secretions in children compared with adults

Background. In contrast to adults, ulcers are un‐common in Helicobacter pylori‐infected children. Since immunological determinants influence the outcome of H. pylori infection, we have investigated mucosal T cell responses in H. pylori‐infected children and compared them with those of adults and negative controls. Material and Methods. Mucosal biopsies were obtained from 43 patients undergoing an upper GI endoscopy for dyspeptic symptoms. The concentrations of released cytokines and the density of CD3⁺, CD25⁺ and CD69⁺cells were evaluated by flow cytometry, and the numbers of cytokine‐secreting cells were measured by ELISPOT. Results. The numbers of isolated antral CD3⁺ lymphocytes were only significantly raised in infected adults compared with noninfected controls (p < 0.05), whereas the proportion of CD3⁺ cells expressing activation markers (CD25 or CD69) remained low. In the stomach, IFN‐γ concentrations increased in infected children and infected adults compared with controls (p < 0.05), but IFN‐γ concentrations were tenfold lower in children than in adults (p < 0.01). IL‐2, IL‐4, IL‐10 and TNF‐α concentrations were similar in infected and in uninfected children and adults. In contrast, in the duodenum, IFN‐γ, as well as IL‐4 and IL‐10 concentrations were only increased in infected children compared with controls (p < 0.05). The concentrations of these cytokines were similar in both groups of adults who, however, like children, displayed a higher number of duodenal IL‐4‐secreting cells compared to controls (p < 0.05). Conclusion. These results suggest that IFN‐γ secretion in the stomach of H. pylori‐infected patients is lower in children than in adults. This could protect children from development of severe gastro‐duodenal diseases such as ulcer disease. In addition, infected patients are characterised by a dysregulation of the mucosal cytokine secretion at distance from the infection site.     

Parallel phenotypic evolution in a wolf spider radiation on Galápagos

Within island archipelagos, repeated ecological settings may lead to radiations wherein similar niches are recurrently occupied. Although it has been shown that species with common habitat requirements share particular traits, it remains relatively unexplored to what extent this may lead to the repeated evolution of almost identical phenotypes (phenocopies) and how this correlates with traits subjected to sexual selection. Exploring divergence patterns of ecological and sexual relevant traits within spiders seem promising to enhance our understanding of the relative role of natural and sexual selection. Here, we conduct a detailed morphological analysis on a large set of genital and non‐genital traits (morphometrics, colour pattern) within a radiation of the wolf spider genus Hogna Simon, 1885 on Galápagos and interpret these data, taking into account their known phylogenetic relationship. Our results show that recurrent environmental gradients have led to the parallel evolution of almost identical phenotypes, which not only proves that natural selection has driven morphological divergence, but also suggests that a similar genetic or developmental basis most likely underlies this divergence. Among‐species variation in genital traits in contrast rather reflects the phylogenetic relationships on Santa Cruz and San Cristóbal. The combination of these data indicate that speciation in this system is driven by the combined effect of ecological mechanisms and allopatric divergence in sexual traits. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106 , 123–136.     

Limited secretory-IgA response in cervicovaginal secretions from HIV-1 infected, but not high risk seronegative women: lack of correlation to genital viral shedding

The presence and antigen specificity of IgG and secretory-IgA (s-IgA) to HIV-1 were evaluated in cervicovaginal lavages (CVL) from 26 infected and 10 high-risk seronegative women. All the seropositive women had detectable IgG recognizing several viral antigens, while a smaller percentage of women demonstrated s-IgA to the virus. In addition, s-IgA were of limited specificity and provided weak reactivities on Immunoblot bands; an almost constant absence of s-IgA to gp120 was also observed. Neither the presence nor the specificity of either IgG or s-IgA to the virus in CVL prevented the shedding of HIV-1 in this body fluid; in fact, viral RNA was detected in all the women studied and the amounts of viral shedding was unrelated to the genital antibody response. On the other hand, none of the high-risk seronegative women had detectable antibodies to HIV-1 in CVL of either the IgG or s-IgA isotype. Our results a) confirm an impairment of mucosal antibody response during HIV-1 infection and suggest that mucosal immunity is not able to prevent viral shedding in the female genital tract and thus cannot modulate the infectivity of genital secretions; aa) do not provide evidence for a mucosal "memory/protective" antibody response in the genital tract of high-risk seronegative women.     

Expression of ABC-1 transporter is elevated in human glioma cells under irradiation and temozolomide treatment

Summary. Objective: Chemo-therapeutic treatment of glioma patients has minor success. Little is known about mechanisms of a pronounced resistance of gliomas towards actual therapies, yet. ABC-1 belongs to the group of transporters known to be involved in the export of hydrophobic substances and vascular regulation. This study investigates an effect of both temozolomide (TMZ) treatment and/or irradiation on the expression of the ABC-1 transporter in human U87-MG glioma cells.Material and methods: In parallel experiments U87-MG cells underwent either irradiation (RT), chemo-treatment (CT) using TMZ, and combined chemo/radiation-treatment (CT/RT). After each treatment the cells were incubated either 2 or 24 hours at 37°C and counted before protein analysis using Western-Blot technique.Results and conclusions: An exponential growth of cellular density was observed for both untreated and irradiated cells being, however, about 2-times slower in irradiated compared to untreated cells. In contrast the density increase of chemo-treated cells as well as that of cells, which underwent the combined CT/RT treatment was of linear nature. ABC-1 expression was detected in untreated as well as treated cells. Increasing cell density and all kinds of treatment resulted in a considerably enhanced ABC-1 expression. CT treatment resulted in highly up-regulated ABC-1 expression especially in non-confluent cultures compared to untreated cells. Irradiation had a comparable or even higher inducible effect on the ABC-1 expression rates depending, however, on cell density. The highest expression rates were observed in cultures with high cellular density 2 hours after application of the combined treatment. Strong up-regulation of ABC-1 expression under both irradiation and chemo-treatment might be a clue to multidrug and irradiation cross-resistance mechanisms of malignant glioma cells converting the ABC-1 transporter into an attractive pharmacological target for a clinical breakthrough in the therapy of malignant gliomas.