CCR6-mediated dendritic cell activation of pathogen-specific T cells in Peyer's patches

T cell activation by dendritic cells (DCs) is critical to the initiation of adaptive immune responses and protection against pathogens. Here, we demonstrate that a specialized DC subset in Peyer's patches (PPs) mediates the rapid activation of pathogen specific T cells. This DC subset is characterized by the expression of the chemokine receptor CCR6 and is found only in PPs. CCR6(+) DCs were recruited into the dome regions of PPs upon invasion of the follicle associated epithelium (FAE) by an enteric pathogen and were responsible for the rapid local activation of pathogen-specific T cells. CCR6-deficient DCs were unable to respond to bacterial invasion of PPs and failed to initiate T cell activation, resulting in reduced defense against oral infection. Thus, CCR6-dependent regulation of DCs is responsible for localized T cell dependent defense against entero-invasive pathogens.     

In vitro bioactivity and osteoblast response of porous NiTi synthesized by SHS using nanocrystalline Ni-Ti reaction agent

Porous NiTi with an average porosity of 55 vol % and a general pore size of 100-600 microm was synthesized by self-propagating high temperature synthesis (SHS) with the addition of mechanically alloyed nanocrystalline Ni-Ti as the reaction agent. The SHS of porous NiTi using elemental powders was also performed for comparison. To enhance the bioactivity of the metal surface, porous NiTi synthesized by nanocrystalline Ni-Ti was subjected to chemical treatment to form a layer of TiO(2) coating. The porous NiTi with TiO(2) coating was subsequently immersed in a simulated body fluid (SBF) to investigate its apatite forming ability. The effects of the addition of nanocrystalline Ni-Ti as reaction agent and the application of apatite coating on osteoblastic behavior were studied in primary cultures of human osteoblast cells. Results showed that the main phases in porous NiTi synthesized by elemental powders were NiTi, Ti(2)Ni, and unreacted free Ni. By using nanocrystalline Ni-Ti as reaction agent, the secondary intermetallic phase of Ti(2)Ni was significantly reduced and the free Ni was eliminated. TiO(2) coating with anatase phase was formed on the surface of porous NiTi after the chemical treatment. A layer consisting of nanocrystalline carbonate-containing apatite was formed on the surface of TiO(2) coating after soaking in SBF. The preliminary cell culture studies showed that the porous NiTi synthesized with the addition of nanocrystalline Ni-Ti attracted marked attachment and proliferation of the osteoblast cells. This gives the evidence of the potential biomedical applications of the porous NiTi.     

Mutations in the RNA component of RNase mitochondrial RNA processing might cause Omenn syndrome

BACKGROUND: Omenn syndrome is a variant of severe combined immunodeficiency disease, which most prominently presents with erythroderma, eosinophilia, and susceptibility to various pathogens. Mutations in the nucleases of recombination activating genes 1 and 2 (RAG1/RAG2) or Artemis were found in some, but not all, patients with Omenn syndrome. We identified 2 patients who presented with clinical features consistent with Omenn syndrome but had no mutations in RAG or Artemis. Both patients also had cartilage-hair hypoplasia (CHH). OBJECTIVES: We sought to define the molecular basis and characterize the features of severe combined immunodeficiency and Omenn syndrome in these patients. METHODS: We have studied humoral and cellular immunity using standard assays. T-cell repertoire was investigated by quantitating Vbeta families. The RNase mitochondrial RNA processing (RMRP) RNA gene was sequenced by using standard techniques. RESULTS: Sequence analysis of the RMRP RNA gene showed that each patient had an insertion-duplication on one allele and a point mutation on the other allele. These point mutations were novel, and they might be related to the unusual presentation of Omenn syndrome in addition to CHH in these patients. Indeed, analysis of the thymus showed residual mature T lymphocytes. This leaky thymus might be responsible for the skewed release of some T-cell clones into the circulation, which might trigger the phenotype of Omenn syndrome. CONCLUSION: We have demonstrated that mutations in the RMRP RNA gene might be associated with Omenn syndrome. CLINICAL IMPLICATIONS: This discovery will aid clinicians in the early recognition and treatment of CHH-associated Omenn syndrome.     

How Much Do We Know about Atopic Asthma： Where Are We Now？

Asthma is a common disease in the worldwide and it affects over 3.5 million adults and children in the UK. Asthma is a chronic disease characterized by airway hyperresponsiveness, airway inflammation, airway remodelling and reversible airway obstruction. Inflammatory cells, cytokines, chemokines, adhesion molecules, and mediators are involved in pathogenesis of asthma. Chronic airway inflammation and remodelling are the major characters in asthma, which result in decreased pulmonary function. The precise processes are far understood at moment. Although corticosteroid therapy plus other exiting drugs （bronchodilators and oral leukotriene receptor antagonists） influences many different inflammatory and structural cell types and continues to be as the ＂gold standard＂ of therapy in asthma, many thousands have chronic, severe diseases and suffer daily symptoms which make their lives a misery. There remains a clear need for novel approaches to therapy, which will be informed by a clearer understanding of disease pathogenesis, particularly in the target organ where airway inflammation and remodelling, the hallmarks of asthma occur. Cellular ＆ Molecular Immunology.     

创新思维对肾移植模型制作教学的促进作用

大鼠肾移植模型是研究肾移植排斥反应发生机制、治疗措施以及诱导免疫耐受的重要平台,但其制作复杂,在传统教学中存在诸多问题。对此,我们在教学中充分发挥创新思维,改进了教学方式,建立了多项新技术,显著提高了以显微外科技术为基础的大鼠肾移植模型制作的教学效率与质量,现将体会报告如下。1应用现代教学手段解决传统教学中的难题1.1大鼠肾移植模型的制作特点以及传统教学存在的问题该模型制作主要依赖显微外科技术,教学中,从解剖结构、手术器械到手术操作的突出特点是“精细、微小”,也是教学的难点。传统教学主要依靠文字教材以及部分挂…     

鼻咽癌患者血清TGF-β1、IL-8水平和T淋巴细胞亚群水平测定的临床意义

目的：探讨了鼻咽癌患者血清TGF-β1、IL-8和T淋巴细胞亚群水平的变化及意义。方法：分别应用放免法、酶联免疫法和单克隆抗体测定对31例鼻咽癌患者进行了血清TGF-β1、IL-8水平和T淋巴细胞亚群的测定,并与35例正常健康人作比较。结果：鼻咽癌患者血清TGF-β1、IL-8和CD8水平非常显著高于正常人组（P〈0．01）,而CD3、CD4、CD4／CD8比值又非常显著低于正常人组（P〈0．01）。鼻咽癌患者血清TGF-β1水平和CD4细胞数量及与CD4／CD8比值呈负相关,与CD8细胞呈正相关。结论：观察鼻咽癌患者血清TGF-β1、IL-8水平和T淋巴细胞亚群水平的改变有助于鼻咽癌的诊断及对预后的评价。     

An outbreak of avian influenza subtype H9N8 among chickens in South Korea.

Low pathogenic avian influenza subtype H9N8 was diagnosed on a Korean native chicken farm in Gyeonggi province, South Korea, in late April 2004. Clinical signs included moderate respiratory distress, depression, mild diarrhoea, loss of appetite and a slightly elevated mortality (1.4% in 5 days). Pathologically, mucopurulent tracheitis and air sacculitis were prominently found with urate renal deposition. The isolated A/chicken/Kr/164/04 (H9N8) had an Ala-Ser-Gly-Arg (A/S/G/R) motif at the cleavage site of haemagglutinin, which has been commonly found in H9N2 isolated from Korean poultry. Phylogenetic analysis of the haemagglutinin and neuraminidase genes of the H9N8 avian influenza virus (AIV) isolate showed that reassortment had occurred. Its haemagglutinin gene was similar to that of Korean H9N2 AIVs, but its neuraminidase gene was closely related to that of A/WBF/Kr/KCA16/03 (H3N8) isolated from the faeces of wild birds in Korea. The pathogenicity of the isolate was tested on 6-week-old specific pathogen free chickens. The inoculated virus (H9N8) was recovered from most tested organs, including the trachea, lung, kidney, spleen, and caecal tonsil. This is the first report of an outbreak of low pathogenic avian influenza in chickens caused by AIV subtype H9N8.     

Ca2+-desensitizing hypoxic vasorelaxation: pivotal role for the myosin binding subunit of myosin phosphatase (MYPT1) in porcine coronary artery

Acute hypoxia dilates most systemic arteries leading to increased tissue perfusion. We showed that at high stimulus conditions, porcine coronary artery was relaxed by hypoxia without a change in [Ca²⁺]_i. This 'Ca²⁺-desensitizing hypoxic relaxation' was validated in permeabilized porcine coronary artery smooth muscle (PCASM) in which hypoxia decreased force and myosin regulatory light chain phosphorylation (p-MRLC) despite fixed [Ca²⁺]. Rho kinase-dependent phosphorylation of MYPT1 (p-MYPT1) is associated with decreased MRLC phosphatase (MLCP) activity, and increased Ca²⁺ sensitivity of both p-MRLC and force. We tested the hypothesis that hypoxia induces Ca²⁺-desensitizing hypoxic relaxation via dephosphorylation of p-MYPT1, consequently increasing MLCP activity and thus decreasing p-MRLC. α-Toxin-permeabilized PCASM pretreated with ATPγS did not relax in response to hypoxia. Moreover, when MRLC but not MYPT1 was protected from ATPγS thiophosphorylation by the MRLC kinase inhibitor ML7 (300 μ m ), hypoxia remained ineffective. In contrast, hypoxic relaxation was preserved with further addition of the Rho kinase inhibitor Y27632 (1 μ m ), to attenuate thiophosphorylation of MYPT1. Importantly, measurements of p-MRLC, and p-MYPT1 at T696 and T853 (human sequence) paralleled that of force. We conclude that Ca²⁺-desensitizing hypoxic relaxation requires dephosphorylation of p-MYPT1. Moreover, no kinases, other then those inhibited by ML7 and Y27632, nor their associated phosphoproteins can be involved in Ca²⁺-desensitizing hypoxic relaxation.     

HLA alleles and haplotypes in French North African immigrants

Human leukocyte antigen (HLA) haplotypes (n = 187) were genotyped and assigned by the mode of inheritance in migrant families from North Africa who reside in the Paris, France, area. The distribution of alleles and haplotypes in that population was compared with the one obtained in a control population of ancient French natives residing in the same area (248 independent haplotypes also assigned by the mode of inheritance were studied). The results in migrants reveal the following: (1) a higher diversity in the distribution of HLA-A and -DRB1 alleles; (2) lower frequencies of alleles common in our region, such as A*0201 B*1501, B*4001, and DRB1*0401 and increased frequencies of minor subtypes, such as A*3002 and DRB1*0402; and (3) distinct distributions of B/Cw, DRB1/DQB1 or B/Cw/DRB1/DQB1 haplotypes. The results also revealed that the four most frequent five-allele haplotypes in controls i.e., HLA-A*0101/B*0801/Cw*0701/DRB1*0301/DQB1*0201; A*0301/B*0702/Cw*0702/DRB1*1501/DQB1*0602 (both of Indo-Celtic origin); A*2902/B*4403/Cw*1601/DRB1*0701/DQB1*0202 (frequent in Western-Europeans); and A*0201/B*1501/Cw*0304/DRB1*0401/DQB1*0302, represent 10.5% of the total haplotypes in controls but 1.6% in North Africans. Conversely, 9 five-allele haplotypes in multiple copy in North Africans (among which A*3002/B*1801/Cw*0501/DRB1*0301/DQB1*0201 of Paleo-North African origin and A*0201/B*0702/Cw*0702/DRB1*1501/DQB1*0602 of ancient European and Paleo-North African origin) represent 9.6% of the total haplotypes in North Africans but 2.4% in controls. These results thus suggest a low degree of admixture between the two populations.     

Establishment of the major compatibility complex-dependent development of CD4+ and CD8+ T cells by the Cbl family proteins

Casitas B cell lymphoma (Cbl) proteins are negative regulators for T cell antigen receptor (TCR) signaling. Their role in thymocyte development remains unclear. Here we show that simultaneous inactivation of c-Cbl and Cbl-b in thymocytes enhanced thymic negative selection and altered the ratio of CD4(+) and CD8(+) T cells. Strikingly, the mutant thymocytes developed into CD4(+)- and CD8(+)-lineage T cells independent of the major histocompatibility complex (MHC), indicating that the CD4(+)- and CD8(+)-lineage development programs are constitutively active in the absence of c-Cbl and Cbl-b. The mutant double-positive (DP) thymocytes exhibited spontaneous hyperactivation of nuclear factor-kappa B (NF-kappaB). Additionally, they failed to downregulate the pre-TCR and pre-TCR signaling. Thus, our data indicate that Cbl proteins play a critical role in establishing the MHC-dependent CD4(+) and CD8(+) T cell development programs. They likely do so by suppressing MHC-independent NF-kappaB activation, possibly through downmodulating pre-TCR signaling in DP thymocytes.