Decreased DMT1 and increased ferroportin 1 expression is the mechanisms of reduced iron retention in macrophages by erythropoietin in rats

Recycled iron from reticuloendothelial macrophages to erythroid precursors is important to maintain the iron homeostasis. However, the molecular mechanisms underlying iron homeostasis in macrophages are poorly understood. In this study, male Sprague-Dawley rats were treated with recombinant human erythropoietin (rHuEpo, 500 IU/day, s.c.) for 3 days. At the fifth day, peritoneal exudate macrophages were harvested, and then (55)Fe uptake and release were measured by liquid scintillation counting method. The expression of divalent metal transporter 1 (DMT1) and ferroportin 1 (FPN1) in peritoneal exudate macrophages was detected by RT-PCR and Western blot. In order to exclude the direct effect of rHuEpo on macrophages, the parallel experiments were performed with incubation normal peritoneal exudate macrophages with rHuEpo (2 IU/ml). Our results showed rHuEpo injection reduced the peritoneal exudate macrophages iron retention. The uptake of Fe(II) was decreased via the suppression of DMT1 (+IRE) expression and the release of Fe(II) was increased with increasing the expression of FPN1 in macrophages. Moreover, the expression of HAMP mRNA was four times lower in rHuEpo-treated liver of rats than control group (CG). HAMP mRNA expression was increased; the synthesis of DMT1 had no significant change, whereas the FPN1 was decreased in normal peritoneal exudate macrophages after treatment with rHuEpo in vitro. We conclude that hepcidin may play a major, causative role in the change of FPN1 synthesis and that decreased the iron retention in macrophages of rHuEpo-treated rats.     

呼吸道合胞病毒疫苗研究进展

呼吸道合胞病毒(RSV)是引起婴幼儿支气管炎和肺炎的主要原因,并可致免疫缺陷病人显著发病和死亡,RSV疫苗已被WHO列为全球最优先发展的疫苗之一。经过几十年的研究,虽然取得了显著进展,但尚未有RSV疫苗上市。目前RSV疫苗的研究主要集中于亚单位疫苗、减毒活疫苗和DNA疫苗等,其中亚单位疫苗和减毒活疫苗被认为最有前途,已分别进行了的临床试验。     

叶绿体——疫苗生产新工厂

以叶绿体为受体的叶绿体基因工程技术已经在工农业及医药生物技术领域发挥了重要作用。利用叶绿体为基因转移受体的叶绿体基因工程技术来生产疫苗是目前人们关注的焦点。现着重在叶绿体作为遗传工程受体的特点、叶绿体基因工程的研究进展,它在疫苗生产中的应用及发展前景等方面进行综述。     

登革病毒疫苗研究现状与展望

登革病毒是属于黄病毒科的小型包膜病毒,在热带和亚热带地区通过蚊媒传播。其感染可引起临床症状轻微的登革热,甚至危及生命的登革出血热和登革休克综合征。登革病毒包含4种血清型,有效的登革病毒疫苗需对4种血清型的登革病毒均具有抗病毒保护作用。目前,尚未有针对登革病毒的特效药和成熟的疫苗产品。各类登革病毒疫苗均在研发中,其中一些已进入临床试验阶段。本文就登革病毒疫苗研究进展作一综述并对未来发展进行展望。     

Comparison of immune responses against FMD by a DNA vaccine encoding the FMDV/O/IRN/2007 VP1 gene and the conventional inactivated vaccine in an animal model

Foot-and-mouth disease virus (FMDV) is highly contagious and responsible for huge outbreaks among cloven hoofed animals. The aim of the present study is to evaluate a plasmid DNA immunization system that expresses the FMDV/O/IRN/2007 VP1 gene and compare it with the conventional inactivated vaccine in an animal model. The VP1 gene was sub-cloned into the unique Kpn I and BamH I cloning sites of the pcDNA3.1+ and pEGFP-N1 vectors to construct the VP₁ gene cassettes. The transfected BHKT7 cells with sub-cloned pEGFP-N1-VP1 vector expressed GFP-VP1 fusion protein and displayed more green fluorescence spots than the transfected BHKT7 cells with pEGFP-N1 vector, which solely expressed the GFP protein. Six mice groups were respectively immunized by the sub-cloned pcDNA3.1⁺-VP1 gene cassette as the DNA vaccine, DNA vaccine and PCMV-SPORT-GMCSF vector (as molecular adjuvant) together, conventional vaccine, PBS (as negative control), pcDNA3.1⁺ vector (as control group) and PCMV-SPORT vector that contained the GMCSF gene (as control group). Significant neutralizing antibody responses were induced in the mice which were immunized using plasmid vectors expressing the VP1 and GMCSF genes together, the DNA vaccine alone and the conventional inactivated vaccine (P<0.05). Co-administration of DNA vaccine and GMCSF gene improved neutralizing antibody response in comparison with administration of the DNA vaccine alone, but this response was the most for the conventional vaccine group. However, induction of humeral immunity response in the conventional vaccine group was more protective than for the DNA vaccine, but T-cell proliferation and IFN-γ concentration were the most in DNA vaccine with the GMCSF gene. Therefore the group that was vaccinated by DNA vaccine with the GMCSF gene, showed protective neutralizing antibody response and the most Th1 cellular immunity.     

阿尔茨海默病核酸疫苗的构建及诱导体液免疫反应的初步研究

近年,内源性蛋白主动免疫预防和治疗阿尔茨海默病(AD)的策略成为AD研究领域的热点,并获得迅猛发展。构建了以β-片层结构的淀粉样蛋白(AB)及其可溶性与病理性突变体为抗原基因的DNA疫苗用于免疫小鼠,经过对免疫方案的探索和调整,结果能够打破其自身耐受,在外周血中诱发出较高滴度的抗-AB抗体。初步探讨了诱导体液免疫学效应的规律。并在原代培养的海马神经元AB毒性模型中验证了免疫后血清的生物学活性。     

HIV-1 Neutralizing Antibody Signatures and Application to Epitope-Targeted Vaccine Design

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Novel recombinant human lactoferrin: Differential activation of oxidative stress related gene expression

Lactoferrin, an iron-binding protein found in high concentrations in mammalian exocrine secretions, is an important component of the host defense system. It is also a major protein of the secondary granules of neutrophils from which is released upon activation. Due to its potential clinical utility, recombinant human lactoferrin (rhLF) has been produced in various eukaryotic expression systems; however, none of these are fully compatible with humans. Most of the biopharmaceuticals approved by the FDA for use in humans are produced in mammalian expression systems. The Chinese hamster ovary cells (CHO) have become the system of choice for proteins that require post-translational modifications, such as glycoproteins.     

幽门螺杆菌HspA融合蛋白口服疫苗的构建

构建表达幽门螺杆菌的保护性抗原分热休克蛋白A亚单位(HspA）和霍乱毒素B亚单位（CtxB）的重组融合蛋白的生物工程菌株,以此制备幽门螺杆菌的口服疫苗。用PCR方法扩增hspA和ctxB两个目的的基因片段,将它们分别克隆至pSK（＋）质粒上,然后插入含T7启动子ET－22b（＋）的表达载体中,构建嗓基因的表达质量pET－hct,转化E.coliBL21(DE3）,经IPTG诱导表达融合蛋白HCT。经测序,hspA-ctxB(hct)融合基因片段由726bp组成,可以编码242个氨基酸残基的多肽。经SDS－PAGE和免疫印迹分析检测发现,融合基因表达的蛋白质相对分子质量约为30kD。融合蛋白经镍离子柱纯化、复性后,和HspA共同标记同位素^125I,然后给小鼠灌胃,结果观察到HCT组小鼠血清中的^125I的放射量要明显高于HspA组（P＜0．001）,且吸收峰值时间明显提前。融合蛋白中的CtxB可明显促进小鼠对HspA的吸收,HCT融合蛋白可以作为预防和治疗幽门螺杆菌感染的侯选口服疫苗。     

应用乙型肝炎疫苗阻断围产期乙型肝炎病毒的母婴传播

993名HBsAg携带者母亲所生新生儿,以768名新生儿为试验组,226名新生儿为对照组,试验组分别注射HBsAg血源性氢氧化铝佐剂疫苗,乙型肝炎高价免疫球蛋白(HBlg)或疫苗加HBIg,对照组注射安慰剂,所用疫苗为国产81-2、82-1-2、83-1和美国NIHA9,观察表明,出生后六个月,试验组各批疫苗的保护率为60～93％,以83-1批为最高;疫苗加HBIg的保护效果与疫苗相似,HBIg组亦有70％的保护效果,以上结果证明单独应用HBsAg疫苗阻断母婴传播的效果是理想的。