Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0042961 (volvulus)
 4,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cell-adhesion receptors mediate the interaction between host effector cells and cellular or multicellular targets, including opsonized parasites. Our recent finding of a deposition of plasma proteins, including fibronectin, on the surface of infective larvae of the helminthic parasite Onchocerca volvulus led us to investigate the possible expression of cell-adhesion molecules (CAM), particularly fibronectin receptors, on eosinophilic granulocytes from persons infected with O. volvulus. Immunofluorescence analyses showed that freshly isolated eosinophils strongly expressed the beta 2-integrin CR3 and exhibited to a lower degree CR4 and the integrin-associated carbohydrate determinant Le(x), as well as antigen p24 (CD9). Eosinophils exposed to the eosinophil-active cytokines recombinant human interleukin 3 (rhIL-3) and granulocyte/macrophage colony-stimulating factor (rhGM-CSF) in addition to CR3, CR4, and CD9 expressed the beta 1-integrins VLA-4 and to a lesser extent VL-5 (both fibronectin receptors) as well as the intercellular adhesion molecule ICAM-1. Low-level expression of these adhesins was also observed on eosinophils cultured in the presence of these interleukins on confluent fibroblasts. The presence of VLA-4 as well as VLA-5 on activated eosinophils was confirmed by demonstration of the formation of immune rosettes using antibody-coated microspheres and by their attachment to fibronectin-coated surfaces. These results indicate the possibility of an involvement of previously unidentified antibody- and complement-independent mechanisms in cellular interactions with the parasite O. volvulus.
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PMID:Cell-adhesion molecules expressed by activated eosinophils in Onchocerca volvulus infection. 750 39

We examined the immunogenicity of various connective tissue proteins in patients with chronic onchocercal dermatitis and the effect of filarial proteases on this host-parasite interaction. Sera from patients with onchocerciasis reacted strongly with cuticular collagens from filarial parasites and with mammalian laminin. Some sera also contained antibodies to elastin and collagen type IV, but none reacted with collagen types I-III or fibronectin. This pattern of reactivity was characteristic for onchocerciasis: sera from patients with mansonellosis reacted strongly with collagen type IV but only weakly with laminin. Reactivity with mammalian laminin or collagen could not be absorbed with cuticular proteins from filarial worms and vice versa. Digestion fragments of laminin treated with filarial proteases retain antigenic determinants recognized by sera from patients with onchocerciasis. In contrast, proteases from Onchocerca volvulus adults and microfilariae drastically decreased the reactivity of the same sera with collagen type IV. These results indicate that filarial proteases may contribute to the pathogenesis of chronic onchocercal dermatitis, directly, by enzymatically destroying connective tissue of the skin, and indirectly, by triggering autoimmune responses to self-determinants on connective tissue proteins that are normally hidden within the supramolecular structure of the extracellular matrix complex.
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PMID:Pathogenesis of onchocercal dermatitis: possible role of parasite proteases and autoantibodies to extracellular matrix proteins. 752 5

Host tissue penetration by parasitic nematodes may be mediated by both mechanical processes and proteolytic enzymes released by the parasites. Analysis of excretory-secretory (ES) products of Onchocerca volvulus microfilariae and adult stages on substrate gels demonstrated that they contain several distinct proteolytic enzymes. The analysis of the ES products of the microfilariae revealed one low and two high molecular weight proteolytic bands that degraded gelatin in substrate gels. The low molecular weight protein was found to be an elastinolytic protease cleaving soluble and insoluble elastin. ES products of males contained several high molecular weight proteases in the range of >/= 100-kDa degrading gelatin but lacked the low elastinolytic protease. The ES proteases of both developmental stages degraded the extracellular matrix proteins fibronectin, laminin, and collagen type IV, but not intact immunoglobulin G. The optimal protease activity for each of the proteases was found to be at a neutral pH. Inhibitor studies demonstrated their classification as serine and metalloproteases. Female and male extracts were able to hydrolyze azocasein but not gelatin in substrate gels. Protease activity could not be detected in ES products of females and microfilariae extract.
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PMID:Onchocerca volvulus: microfilariae secrete elastinolytic and males nonelastinolytic matrix-degrading serine and metalloproteases. 970 27