Rapid progression to AIDS in HIV+ individuals with a structural variant of the chemokine receptor CX3CR1

Human immunodeficiency virus (HIV) enters cells in vitro via CD4 and a coreceptor. Which of 15 known coreceptors are important in vivo is poorly defined but may be inferred from disease-modifying mutations, as for CCR5. Here two single nucleotide polymorphisms are described in Caucasians in CX3CR1, an HIV coreceptor and leukocyte chemotactic/adhesion receptor for the chemokine fractalkine. HIV-infected patients homozygous for CX3CR1-I249 M280, a variant haplotype affecting two amino acids (isoleucine-249 and methionine-280), progressed to AIDS more rapidly than those with other haplotypes. Functional CX3CR1 analysis showed that fractalkine binding is reduced among patients homozygous for this particular haplotype. Thus, CX3CR1-I249 M280 is a recessive genetic risk factor in HIV/AIDS.     

CX3CL1在不同品种鸡骨骼肌发育中的表达模式及相关性分析

趋化因子CX3CL1(chemokine(C-X3-Cmotif)ligand 1)与受体CX3CR1结合后,激活MAPK通路调控骨骼肌细胞的增殖和分化。以矮小品系S2系和隐性白羽鸡作为试验素材,采用Q-PCR技术及SPSS分析软件,研究CX3CL1在2个品种胚胎期至生长期骨骼肌发育中的表达模式及相关性分析。结果表明,在S2系鸡,CX3CL1在胚胎期胸肌组织的表达显著低于出雏后的各个发育时期(P0.05);隐性白羽鸡10胚龄时CX3CL1的表达量显著高于其他胚龄及出雏后4、6和8周的表达(P0.05);除16周龄以外,CX3CL1在隐性白羽鸡胸肌组织各个时期的表达都显著高于S2系(P0.05);CX3CL1的表达与胸肌率的相关性分析表明,CX3CL1的表达与2品种胸肌率呈显著正相关。在腿肌组织中,CX3CL1在S2系和隐性白羽鸡的表达呈现显著的品种差异性,除10胚龄外,CX3CL1在隐性白羽鸡其他发育时期的表达都显著高于S2系。综合CX3CL1在2品种的胸肌和腿肌组织中的发育模式及相关性分析表明,CX3CL1在鸡胚胎期和生长期骨骼肌中的表达存在显著的品种和组织差异性。     

Microbial exposure during early life has persistent effects on natural killer T cell function

Exposure to microbes during early childhood is associated with protection from immune-mediated diseases such as inflammatory bowel disease (IBD) and asthma. Here, we show that in germ-free (GF) mice, invariant natural killer T (iNKT) cells accumulate in the colonic lamina propria and lung, resulting in increased morbidity in models of IBD and allergic asthma as compared with that of specific pathogen-free mice. This was associated with increased intestinal and pulmonary expression of the chemokine ligand CXCL16, which was associated with increased mucosal iNKT cells. Colonization of neonatal-but not adult-GF mice with a conventional microbiota protected the animals from mucosal iNKT accumulation and related pathology. These results indicate that age-sensitive contact with commensal microbes is critical for establishing mucosal iNKT cell tolerance to later environmental exposures.     

Monitoring of blood vessels and tissues by a population of monocytes with patrolling behavior

The cellular immune response to tissue damage and infection requires the recruitment of blood leukocytes. This process is mediated through a classical multistep mechanism, which involves transient rolling on the endothelium and recognition of inflammation followed by extravasation. We have shown, by direct examination of blood monocyte functions in vivo, that a subset of monocytes patrols healthy tissues through long-range crawling on the resting endothelium. This patrolling behavior depended on the integrin LFA-1 and the chemokine receptor CX(3)CR1 and was required for rapid tissue invasion at the site of an infection by this "resident" monocyte population, which initiated an early immune response and differentiated into macrophages.     

Requirement of Rac1 and Rac2 expression by mature dendritic cells for T cell priming

Upon maturation, dendritic cells (DCs) acquire the unique ability to activate na?ve T cells. We used time-lapse video microscopy and two-photon imaging of intact lymph nodes to show that after establishing initial contact between their dendrites and na?ve T lymphocytes, mature DCs migrate toward the contacted lymphocytes. Subsequently, the DCs tightly entrap the T cells within a complex net of membrane extensions. The Rho family guanosine triphosphatases Rac1 and Rac2 but not Rho itself control the formation of dendrites in mature DCs, their polarized short-range migration toward T cells, and T cell priming.     

Distribution of S-100 positive dendritic cells in bovine pharynx, tonsils, and retropharyngeal lymph nodes

Dendritic cells (DCs) are professional antigen-presenting cells. However, the distribution of bovine DCs in the pharynx, tonsil, and retropharyngeal lymph nodes has not yet been documented. To address this issue, immunohistochemistry was conducted using S-100 protein as a marker for DCs. It was observed that S-100 positive Langerhans cells (LCs) were primarily found in the basal layer of the pharyngeal epithelium. Some DCs were found in the outer layer of the epithelium and their dendrites extended out towards the epithelial surface. In the tonsil, S-100 positive DCs were found either in follicular germinal centers or in the T-cell areas. It is worth noting that the S-100 positive DCs were not only distributed in the cortex, but also in the medulla of bovine retropharyngeal lymph nodes. The distribution patterns of bovine DCs in the pharynx, tonsil, and retropharyngeal lymph nodes have an important implication for our understanding of the interaction between pathogens and host.     

Differential antigen processing by dendritic cell subsets in vivo

Dendritic cells (DCs) process and present self and foreign antigens to induce tolerance or immunity. In vitro models suggest that induction of immunity is controlled by regulating the presentation of antigen, but little is known about how DCs control antigen presentation in vivo. To examine antigen processing and presentation in vivo, we specifically targeted antigens to two major subsets of DCs by using chimeric monoclonal antibodies. Unlike CD8+ DCs that express the cell surface protein CD205, CD8- DCs, which are positive for the 33D1 antigen, are specialized for presentation on major histocompatibility complex (MHC) class II. This difference in antigen processing is intrinsic to the DC subsets and is associated with increased expression of proteins involved in MHC processing.     

布鲁氏菌核糖体L7/L12蛋白的原核表达及对鼠源树突状细胞的作用

为了研究和探讨布鲁氏菌核糖体L7/L12蛋白对鼠源树突状细胞(BM-DCs)分化和成熟的影响,用布鲁氏菌S2疫苗株为模板扩增L7/L12基因,构建重组质粒pET30a-L7/L12,用大肠埃希菌原核表达系统进行诱导表达,并用Ni柱对表达的蛋白进行纯化.用IL-4和GM-CSF诱导培养鼠源DCs,用脂多糖(LPS)和L7...     

Chemokine Up-regulation and activated T cell attraction by maturing dendritic cells

Langerhans' cells migrating from contact-sensitized skin were found to up-regulate expression of macrophage-derived chemokine (MDC) during maturation into lymph node dendritic cells (DCs). Na?ve T cells did not migrate toward MDC, but antigen-specific T cells rapidly acquired MDC responsiveness in vivo after a subcutaneous injection of antigen. In chemotaxis assays, maturing DCs attracted activated T cells more strongly than na?ve T cells. These studies identified chemokine up-regulation as part of the Langerhans' cell maturation program to immunogenic T cell-zone DC. Preferential recruitment of activated T cells may be a mechanism used by maturing DCs to promote encounters with antigen-specific T cells.     

猪I型补体受体与C3b活性片段相互结合的体外检测

【目的】检测猪红细胞类补体受体I型（Complement receptor 1-like,CR1-like）与C3b活性片段能否发生结合,以期为阐明猪红细胞发挥免疫粘附功能的分子机理提供科学数据。【方法】利用前期已构建的CR1-like_(3-6)、CR1-like_(8-11)功能域片段的重组质粒建立酵母双杂交检测体系,运用酵母共转化的方法将诱饵质粒（重组pGBKT7-CR1-like）与捕获质粒（重组pGADT7-C3b）共同转入Y2HGold酵母细胞中,分别利用一缺平板SD/-Leu、SD/-Trp和二缺平板SD/-Leu/-Trp（DDO）严格筛选共转化成功的酵母细胞,再根据报告因子是否表达来鉴别转化子在SD/-Leu/-Trp/X-α-Gal（DDO/X）、SD/-Leu/-Trp/X-α-Gal/Aba（DDO/X/A）二缺培养板上的生长情况,并结合菌落的颜色变化现象综合判定CR1-like活性片段与补体C3b在酵母细胞中是否发生相互结合;然后运用免疫沉淀技术分离酵母细胞中CR1-like与C3b结合复合物,并对该复合物的特异性进行Western blot鉴定。【结果】试验成功将pGBKT7-CR1-like与pGADT7-C3b基因共转入Y2HGold酵母细胞。共转化的酵母克隆在SD/-Leu、SD/-Trp、DDO平板上能够正常生长,在DDO/X、DDO/X/A平板上正常生长且菌落呈现蓝色,由此表明,试验中酵母双杂交系统建立成功,并通过试验获得了阳性酵母克隆。共同转化了pGBKT7-CR1-like和pGADT7-C3b质粒的酵母菌落PCR反向鉴定结果显示,在共转化的酵母菌中含有目的基因CR1-like_(3-6)和CR1-like_(8-11),共转化组的质粒酶切后出现C3b基因片段,与设计大小一致,说明重组质粒成功共转化入酵母细胞中。免疫沉淀试验中应用pGBKT7载体的标签抗体c-Myc沉淀酵母细胞中的融合蛋白,以c-Myc为一抗进行Western blot检测发现,单独转化了pGBKT7-CR1-like_(3-6)和pGBKT7-CR1-like_(8-11)的融合蛋白在50 kD处出现特异性条带;共转化pGBKT7-CR1-like_(3-6) + pGADT7-C3b和共转化pGBKT7-CR1-like_(8-11) + pGADT7-C3b的酵母融合蛋白在83 kD处出现特异性条带;以HA单克隆抗体为一抗进行Western blot检测时,在pGBKT7-CR1-like_(3-6)和pGBKT7-CR1-like_(8-11)融合蛋白中没有出现特异性条带,只有3、4泳道中共转化的酵母融合蛋白在83 kD处出现特异性条带,表明在Y2HGold酵母细胞中存在CR1-like与C3b识别结合的复合物。使用CR1-like单克隆抗体沉淀酵母细胞中的融合蛋白,以CR1-like单克隆抗体为一抗进行Western blot检测发现,单独转化了pGBKT7-CR1-like_(3-6)和pGBKT7-CR1-like_(8-11)的融合蛋白在50 kD处出现特异性条带;共转化pGBKT7-CR1-like_(3-6) + pGADT7-C3b和共转化pGBKT7-CR1-like_(8-11) + pGADT7-C3b的酵母融合蛋白在83 kD处出现特异性条带;以C3单克隆抗体为一抗进行Western blot检测发现,在pGBKT7-CR1-like_(3-6)和pGBKT7-CR1-like_(8-11)融合蛋白中没有出现特异性条带,泳道3、4所示只有共转化的酵母融合蛋白在83 kD处出现特异性条带,表明在Y2HGold酵母细胞中存在具有生物活性的CR1-like与C3b识别结合的复合物。通过多个单克隆抗体杂交结果,可看出诱饵质粒的表达产物CR1-like_(3-6)、CR1-like_(8-11)片段与捕获质粒的表达产物C3b片段可在酵母细胞内发生结合。【结论】猪红细胞CR1-like发挥免疫粘附功能的识别配体为C3b,为猪红细胞CR1-like功能域分子结构的进一步解析提供了重要数据依据。     

珠眉海棠(Malus zumi Mats)盐应答MzSTO基因的克隆与表达分析

通过微列阵芯片(Microarray)分析,从珠眉海棠盐胁迫cDNA文库中分离得到MzSTO (Salt tolerance protein)全长基因.结果表明:MzSTO基因cDNA全长1 066 bp,开放阅读框共729 bp,5'-UTR和3'-UTR的长度分别是49 bp和288 bp; MzSTO编码242个氨基酸,N端有2个保守的B-box锌指结构域(CX2CX8CX7CX2CX4HX8H);半定量RT-PCR表明MzSTO基因受到盐和干旱胁迫抑制,受冷处理诱导,并响应ABA(abscisic acid).以上结果表明MzSTO基因可能通过依赖ABA的途径参与非生物逆境胁迫.     

TMR饲料对肉用牛生长发育及胴体品质的影响

利用TMR和精.粗分离饲料对去势韩牛进行饲养试验的结果表明,对照组和试验1组的干物质采食量显著高于试验2组和试验3组(P<0.05).在日增重、眼积面积和肌内脂肪度方面对照组和试验1组优于试验2组和试验3组.各处理间的肉色和脂肪色无显著性差异.在肉质肉量方面,肉量A级的出现率对照组和试验3组高于试验1组和试验2组,高级肉的出现率对照组和试验1组优于试验2组和试验3组.从总体上看,在粗饲料需要量较多的育成期应采用TMR饲养体系,而能量需要量较高的育肥期则采用传统的精.粗饲料分离饲喂方式对改善肉牛的产肉性能更为有利.     

单环刺螠幼体生长及摄食强度的研究

为探讨不同饵料(微绿拟球藻、2/3微绿拟球藻+1/3螺旋藻、1/2微绿拟球藻+1/2三角褐指藻)对单环刺螠Urechis unicinctus幼体(体质量约0.5 g)生长的影响,采用室内生态学试验方法测定了单环刺螠幼体的清滤率和滤食率。结果表明:用混合饵料投喂可显著提高单环刺螠幼体的增重率(P0.05);在一定盐度范围内,单环刺螠幼体的清滤率和滤食率均与盐度呈正相关关系;盐度为20~28时幼螠清滤率和滤食率随盐度的升高逐渐增加,盐度为28时达到最大值,幼螠的清滤率为(262.16±3.90)mL/(ind.·h),摄食率为(123.41±0.74)×10~4cells/(ind.·h);温度对幼螠的清滤率和滤食率影响显著(P0.05),温度为15~25℃时,清滤率和滤食率随温度升高逐渐增加,水温为20℃时幼螠的清滤率最高,为(251.33±10.16)mL/(ind.·h),水温为25℃时幼螠的滤食率最高,为(159.11±4.35)×10~4cells/(ind.·h)。研究表明:在较为理想的外界环境下,单环刺螠幼体的增重率与食物来源相关性较大,以混合饵料投喂效果最好;盐度和温度对单环刺螠幼体的摄食有显著的影响,幼体摄食的最适水温为20~25℃,最适盐度为28。     

绵羊发情期输卵管组织结构的观察

采用冰冻切片、H.E染色,对绵羊发情期输卵管各部进行了组织学观察和研究.结果表明,在发情期,绵羊榆卵管伞、漏斗部和壶腹部纵行皱褶黏膜上皮的厚度稍有增加,并且黏膜上皮向固有膜下陷形成一些输卵管腺;腺泡上皮为不太规则的假复层纤毛柱状上皮,由大量分泌细胞和少量的柱状纤毛细胞、基细胞共同构成;输卵管伞、漏斗部和壶腹部,黏膜上皮和腺泡上皮内大部分分泌细胞顶端出现有分泌小泡,而在榆卵管峡部,分泌细胞顶端则没有分泌小泡.绵羊发情期,输卵管伞、漏斗部和输卵管壶腹部在固有膜内出现有榆卵管腺,分泌细胞顶端出现有分泌小泡;峡部的输卵管腺与其他部位的输卵管腺在形态结构和分泌方式上明显不同.     

Differential lysosomal proteolysis in antigen-presenting cells determines antigen fate

Antigen-presenting cells (APCs) internalize antigens and present antigen-derived peptides to T cells. Although APCs have been thought to exhibit a well-developed capacity for lysosomal proteolysis, here we found that they can exhibit two distinct strategies upon antigen encounter. Whereas macrophages contained high levels of lysosomal proteases and rapidly degraded internalized proteins, dendritic cells (DCs) and B lymphocytes were protease-poor, resulting in a limited capacity for lysosomal degradation. Consistent with these findings, DCs in vivo degraded internalized antigens slowly and thus retained antigen in lymphoid organs for extended periods. Limited lysosomal proteolysis also favored antigen presentation. These results help explain why DCs are able to efficiently accumulate, process, and disseminate antigens and microbes systemically for purposes of tolerance and immunity.     

Comment on "HST2 mediates SIR2-independent life-span extension by calorie restriction"

Calorie restriction (CR) increases life span in yeast independently of Sir2. Lamming et al. (Reports, 16 September 2005, p. 1861) recently proposed that Sir2-independent life-span extension by CR is mediated by the Sir2 paralogs Hst1 and Hst2. Contradictory to this, we find that CR greatly increases life span in cells lacking Sir2, Hst1, and Hst2, which suggests that CR is not mediated by Sir2, Hst2, or Hst1.     

雌性双峰驼生殖道粘膜免疫组织和细胞的结构与分布

应用光镜和透射电镜观察12峰雌性双峰驼生殖道粘膜免疫组织和细胞的结构与分布。结果显示，输卵管、子宫和阴道的粘膜上皮以及子宫腺上皮内普遍分布着上皮内淋巴细胞（IEL），尤其在子宫颈后段和阴道前段的上皮中可见淋巴细胞浸润现象。从输卵管伞到阴道，固有膜内分布有数量不等的固有层淋巴细胞（LPL）、浆细胞、巨噬细胞和嗜中性粒细胞，在子宫角、子宫体和子宫颈固有膜中还出现淋巴小结，小结内含有一种成群分布的强嗜伊红细胞，细胞大而有突起。子宫颈粘膜上皮和腺上皮内还见嗜中性粒细胞，这些细胞有时充满于子宫颈腺腔内。在子宫（尤其子宫角）固有膜深层和浅肌层分布着成群的肥大细胞，肥大细胞在孕驼子宫内明显减少。母驼生殖道粘膜形成的众多皱襞和腺体大大增加了上皮表面积，进而增大了粘膜免疫组织和细胞的数量。结果提示，双峰驼生殖道具有强大的粘膜免疫功能。     

A crystal structure of the complex between human complement receptor 2 and its ligand C3d

The interaction of complement receptor 2 (CR2)--which is present on B cells and follicular dendritic cells--with its antigen-bound ligand C3d results in an enhanced antibody response, thus providing an important link between the innate and adaptive immune systems. Although a cocrystal structure of a complex between C3d and the ligand-binding domains of CR2 has been published, several aspects of this structure, including the position in C3d of the binding interface, remained controversial because of disagreement with biochemical data. We now report a cocrystal structure of a CR2(SCR1-2):C3d complex at 3.2 angstrom resolution in which the interaction interfaces differ markedly from the previously published structure and are consistent with the biochemical data. It is likely that, in the previous structure, the interaction was influenced by the presence of zinc acetate additive in the crystallization buffer, leading to a nonphysiological complex. Detailed knowledge of the binding interface now at hand gives the potential to exploit the interaction in vaccine design or in therapeutics directed against autoreactive B cells.     

人工感染小鹅瘟的病理形态学发展规律的研究

5日龄雏鹅口服感染小鹅瘟强毒,观察感染后6、12、24、48、72、96、120h及发病致死鹅的小肠(包括十二指肠、空肠和回肠)、心、肝、肾、胰、脾、腔上囊等器官组织的病变发展规律。其结果为肠道最先出现病变,在感染后6h,即见十二指肠少量绒毛顶端上皮发生脱落;随着感染时间的延长,坏死脱落向绒毛基部发展,绒毛和粘膜固有层炎性细胞浸润逐渐增多。病鹅死之后,整个小肠绒毛上皮及肠腺上皮均发生脱落和坏死,固有层内有大量炎性细胞浸润,局部发生凝固性坏死。心、肝、肾、胰、脾和腔上囊等实质器官在感染初期主要表现为郁血、水肿和间质炎性细胞浸润,后期则表现为实质变化,实质细胞发生萎缩、变性,甚至局灶性坏死。电镜观察表明:肠道病变依次从十二指肠发展至空肠和回肠;感染初期,病毒主要引起肠绒毛顶端上皮的坏死脱落,以后逐渐向绒毛基部发展,固有层裸露,最终绒毛变形,结构消失。     

Induction of protective IgA by intestinal dendritic cells carrying commensal bacteria

The enormous number of commensal bacteria in the lower intestine of vertebrates share abundant molecular patterns used for innate immune recognition of pathogenic bacteria. We show that, even though commensals are rapidly killed by macrophages, intestinal dendritic cells (DCs) can retain small numbers of live commensals for several days. This allows DCs to selectively induce IgA, which helps protect against mucosal penetration by commensals. The commensal-loaded DCs are restricted to the mucosal immune compartment by the mesenteric lymph nodes, which ensures that immune responses to commensal bacteria are induced locally, without potentially damaging systemic immune responses.