Host defense, dendritic cells and the human lung

Host defense mechanisms protect the body against microorganisms and other foreign structures. These mechanisms can be divided in nonspecific, or innate, and specific, or acquired, immunity. In both branches of immunity the several types of leukocytes (white blood cells) play a dominant role. Nonspecific defense comprises the natural barriers that protect against invading microorganisms, the complement system, and various types of white blood cells including granulocytes, monocytes, macrophages and natural killer cells that are able to neutralize microorganisms and foreign material by phagocytosis and/or killing. The natural barriers consist of the epithelial surfaces of the body, such as the skin and the bronchial epithelium. In the lung, junctional complexes between bronchial epithelial cells physically prevent the invasion of microorganisms. In addition, microorganisms and other particles are removed from the respiratory tract by the "tapis roulant": the mucus film propelled towards the oropharyngeal cavity by the cilia of the epithelial cells. The mucus not only serves as vehicle for particle transport, but also contains antibacterial and antiviral proteins. Specific immunity involves the recognition of foreign structures (antigens), the discrimination between self and non-self, and the generation of immunologic memory. A crucial step in the initiation of an immune response is the presentation of antigens to and the stimulation of T cells. Cells capable of antigen-presentation and the stimulation of T cells are called antigenpresenting cells (APC) and comprise monocytes, macrophages, B cells and in particular dendritic cells (DC). Recognition of the presented antigen by the T cell and the generation of costimulatory signals by the APC result in proliferation, cytokine production and a change in marker expression of the T cell. The T cells thereby regulate the activation of several eff

Increased numbers of dendritic cells in the bronchial mucosa of atopic asthmatic patients: Downregulation by inhaled corticosteroids

Background. Dendritic cells (DC) are the most potent antigen-presenting cells (APC) and stimulators of T cells. Dendritic cells are also likely to be essential for the initiation of allergic immune responses in the lung. However, there are not many data on the presence of dendritic cells in the airways of patients with atopic asthma and on the effects of corticosteroid-treatment on such dendritic cells. Objective. We investigated the distribution of dendritic cells in the bronchial epithelium and mucosa of 16 non-smoking atopic asthmatic patients and eight healthy control subjects using detailed immunohistochemistry (CD1a, HLA-DR, L25 as markers for dendritic cells). Methods. Eleven asthmatics were treated for 2.5 years with bronchodilators only and five with bronchodilators and inhaled beclomethasone dipropionate (BDP), 800 μg daily. The patients were randomly sampled from a double-blind multicentre study. Results. There were higher numbers of CD1a+ DC (P = 0.003), L25+ DC (P = 0.002) and HLA-DR expression (P = 0.042) in the bronchial mucosa of asthmatic patients compared with healthy controls. After 2.5 years of treatment, we found a significant increase in flow expiratory volume in 1 second (FEV1) (P = 0.009) and a significant decrease in hyperresponsiveness (PC20 histamine) (P = 0.013) in the corticosteroid group (n = 5) compared with the bronchodilator group (n = 11). This clinical improvement in the corticosteroid-treated group was accompanied by significantly lower numbers of CD1a+ DC (P=0.008), and HLA-DR expression (P=0.028) in the bronchial mucosa than in the bronchodilator-treated group. Conclusion. Our data suggest that dendritic cells are involved in asthmatic inflammation and that corticosteroids may downregulate the number of dendritic

P starvation in tomato

To study the transcriptional changes of plants under P starvation, We performed the time series P starvation in tomato Solanum lycopersicum L. cv Craigella. To investigate the role of strigolactone in these P starvation responses, we also included its SlCCD8 knock down line 16

P starvation in tomato

To study the transcriptional changes of plants under P starvation, We performed the time series P starvation in tomato Solanum lycopersicum L. cv Craigella. To investigate the role of strigolactone in these P starvation responses, we also included its SlCCD8 knock down line 16

TOPAAS, a Tomato and Potato Assembly Assistance System for Selection and Finishing of Bacterial Artificial Chromosomes

We have developed the software package Tomato and Potato Assembly Assistance System (TOPAAS), which automates the assembly and scaffolding of contig sequences for low-coverage sequencing projects. The order of contigs predicted by TOPAAS is based on read pair information; alignments between genomic, expressed sequence tags, and bacterial artificial chromosome (BAC) end sequences; and annotated genes. The contig scaffold is used by TOPAAS for automated design of nonredundant sequence gap-flanking PCR primers. We show that TOPAAS builds reliable scaffolds for tomato (Solanum lycopersicum) and potato (Solanum tuberosum) BAC contigs that were assembled from shotgun sequences covering the target at 6- to 8-fold coverage. More than 90% of the gaps are closed by sequence PCR, based on the predicted ordering information. TOPAAS also assists the selection of large genomic insert clones from BAC libraries for walking. For this, tomato BACs are screened by automated BLAST analysis and in parallel, high-density nonselective amplified fragment length polymorphism fingerprinting is used for constructing a high-resolution BAC physical map. BLAST and amplified fragment length polymorphism analysis are then used together to determine the precise overlap. Assembly onto the seed BAC consensus confirms the BACs are properly selected for having an extremely short overlap and largest extending insert. This method will be particularly applicable where related or syntenic genomes are sequenced, as shown here for the Solanaceae, and potentially useful for the monocots Brassicaceae and Leguminosea