Brugia malayi Asparaginyl–Transfer RNA Synthetase Induces Chemotaxis of Human Leukocytes and Activates G‐Protein–Coupled Receptors CXCR1 and CXCR2
ABSTRACT Background. Lymphatic filariasis is a chronic human parasitic disease in which the parasites repeatedly provoke acute and chronic inflammatory reactions in the host bloodstream and lymphatics. Excretory-secretory products derived from filariae are believed to play an important role in the development of associated immunologic conditions; however, the specific mechanisms involved in these changes are not well understood. Recently, human cytoplasmic aminoacyl-transfer (t) RNA synthetases, which are autoantigens in idiopathic inflammatory myopathies, were shown to activate chemokine receptors on T lymphocytes, monocytes, and immature dendritic cells by recruiting immune cells that could induce innate and adaptive immune responses. Filarial (Brugia malayi) asparaginyl-tRNA synthetase (AsnRS) is known to be an immunodominant antigen that induces strong human immunoglobulin G3 responses.Methods. Recombinant B. malayi AsnRS was used to perform cellular function assays--for example, chemotaxis and kinase activation assays.Results. Unlike human AsnRS, parasite AsnRS is chemotactic for neutrophils and eosinophils. Recombinant B. malayi AsnRS but not recombinant human AsnRS induced chemotaxis of CXCR1 and CXCR2 single-receptor-transfected HEK-293 cell lines, blocked CXCL1-induced calcium flux, and induced mitogen-activated protein kinase.Conclusions. Our findings suggest that a filarial parasite chemoattractant protein may contribute to the development of chronic inflammatory disease and that chemokine receptors may be therapeutic targets to ameliorate parasite-induced pathology.
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- "Similarly, monoclonal antibody 3D6 was shown to inhibit AsnRSinduced chemotaxis in HEK293 cells stably transfected with CXCR2 (Supplemental Fig. 4). AsnRS induced chemotaxis of human leukocytes via interleukin-8 receptors (CXCR1 and CXCR2) is believed to play a role in the inflammatory response and/or immunosuppression induced by Brugia infection in humans (Ramirez et al. 2006). "
ABSTRACT: Diagnosis of eukaryotic parasitic infection using antibody-based tests such as ELISAs (enzyme-linked immunosorbent assays) is often problematic because of the need to differentiate between homologous host and pathogen proteins and to ensure that antibodies raised against a peptide will also bind to the peptide in the context of its three-dimensional protein structure. Filariasis caused by the nematode, Brugia malayi, is an important worldwide tropical disease in which parasites disappear from the bloodstream during daylight hours, thus hampering standard microscopic diagnostic methods. To address this problem, a structural approach was used to develop monoclonal antibodies (mAbs) that detect asparaginyl-tRNA synthetase (AsnRS) secreted from B. malayi. B. malayi and human AsnRS amino acid sequences were aligned to identify regions that are relatively unconserved, and a 1.9 A crystallographic structure of B. malayi AsnRS was used to identify peptidyl regions that are surface accessible and available for antibody binding. Sequery and SSA (Superpositional Structural Analysis) software was used to analyze which of these peptides was most likely to maintain its native conformation as a synthetic peptide, and its predicted helical structure was confirmed by NMR. A 22-residue peptide was synthesized to produce murine mAbs. Four IgG(1) mAbs were identified that recognized the synthetic peptide and the full-length parasite AsnRS, but not human AsnRS. The specificity and affinity of mAbs was confirmed by Western blot, immunohistochemistry, surface plasmon resonance, and enzyme inhibition assays. These results support the success of structural modeling to choose peptides for raising selective antibodies that bind to the native protein.Protein Science 07/2008; 17(6):983-9. DOI:10.1110/ps.073429808 · 2.85 Impact Factor
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ABSTRACT: Summary form only given. This study presents the technology evaluation process in the US electronics manufacturing industry. A survey questionnaire was sent to electronics manufacturing companies in US to collect data about the relationships among the system elements. Multivariate statistical methods and an expert panel were used to quantify and clarify the relationships. The companies in the US electronics manufacturing industry are using eleven major groups of evaluation attributes: flexibility and efficiency, strategic attributes, manufacturing floor requirements, product development, tactical costs, strategic costs, competitiveness, operational social concerns, strategic social concerns, uniqueness, and industry trends. They utilize three major groups of evaluation methodologies: analytic tools, financial tools, and modeling tools. The resulting impacts are: organizational and operational competitiveness, market and new product development competitiveness. The results reveal the following conclusions. Large companies, regardless of their goals and industry segments, use strategic attributes and uniqueness as evaluation attributes. In the case of small companies, segment and goal make a difference in these choices. Companies which are targeting market and new product development competitiveness, use modeling as an evaluation methodology, regardless of their size or segment. This study is providing a guide line for decision makers who are looking for an appropriate technology evaluation strategy for their organizationsManagement of Engineering and Technology, 1999. Technology and Innovation Management. PICMET '99. Portland International Conference on; 02/1999
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ABSTRACT: Infection with parasitic helminths takes a heavy toll on the health and well-being of humans and their domestic livestock, concomitantly resulting in major economic losses. Analyses have consistently revealed bioactive molecules in extracts of helminths or in their excretory/secretory products that modulate the immune response of the host. It is our view that parasitic helminths are an untapped source of immunomodulatory substances that, in pure form, could become new drugs (or models for drug design) to treat disease. Here, we illustrate the range of immunomodulatory molecules in selected parasitic trematodes, cestodes and nematodes, their impact on the immune cells in the host and how the host may recognize these molecules. There are many examples of the partial characterization of helminth-derived immunomodulatory molecules, but these have not yet translated into new drugs, reflecting the difficulty of isolating and fully characterizing proteins, glycoproteins and lipid-based molecules from small amounts of parasite material. However, this should not deter the investigator, since analytical techniques are now being used to accrue considerable structural information on parasite-derived molecules, even when only minute quantities of tissue are available. With the introduction of methodologies to purify and structurally-characterize molecules from small amounts of tissue and the application of high throughput immunological assays, one would predict that an assessment of parasitic helminths will yield a variety of novel drug candidates in the coming years.Parasitology 02/2009; 136(2):125-47. DOI:10.1017/S0031182008005210 · 2.56 Impact Factor