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      The Neutrophil-Activating Protein (Hp-Nap) of Helicobacter pylori Is a Protective Antigen and a Major Virulence Factor

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          Helicobacter pylori infection induces the appearance of inflammatory infiltrates, consisting mainly of neutrophils and monocytes, in the human gastric mucosa. A bacterial protein with neutrophil activating activity (HP-NAP) has been previously identified, but its role in infection and immune response is still largely unknown. Here, we show that vaccination of mice with HP-NAP induces protection against H. pylori challenge, and that the majority of infected patients produce antibodies specific for HP-NAP, suggesting an important role of this factor in immunity. We also show that HP-NAP is chemotactic for human leukocytes and that it activates their NADPH oxidase to produce reactive oxygen intermediates, as demonstrated by the translocation of its cytosolic subunits to the plasma membrane, and by the lack of activity on chronic granulomatous disease leukocytes. This stimulating effect is strongly potentiated by tumor necrosis factor α and interferon γ and is mediated by a rapid increase of the cytosolic calcium concentration. The activation of leukocytes induced by HP-NAP is completely inhibited by pertussis toxin, wortmannin, and PP1. On the basis of these results, we conclude that HP-NAP is a virulence factor important for the H. pylori pathogenic effects at the site of infection and a candidate antigen for vaccine development.

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          Most cited references 72

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          Unidentified curved bacilli on gastric epithelium in active chronic gastritis.

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            Discovery of a novel, potent, and Src family-selective tyrosine kinase inhibitor. Study of Lck- and FynT-dependent T cell activation.

            Here, we have studied the activity of a novel protein-tyrosine kinase inhibitor that is selective for the Src family of tyrosine kinases. We have focused our study on the effects of this compound on T cell receptor-induced T cell activation, a process dependent on the activity of the Src kinases Lck and FynT. This compound is a nanomolar inhibitor of Lck and FynT, inhibits anti-CD3-induced protein-tyrosine kinase activity in T cells, demonstrates selectivity for Lck and FynT over ZAP-70, and preferentially inhibits T cell receptor-dependent anti-CD3-induced T cell proliferation over non-T cell receptor-dependent phorbol 12-myristate 13-acetate/interleukin-2 (IL-2)-induced T cell proliferation. Interestingly, this compound selectively inhibits the induction of the IL-2 gene, but not the granulocyte-macrophage colony-stimulating factor or IL-2 receptor genes. This compound offers a useful new tool for examining the role of the Lck and FynT tyrosine kinases versus ZAP-70 in T cell activation as well as the role of other Src family kinases in receptor function.
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              Helicobacter pylori virulence and genetic geography.

              Isolated for the first time in 1982 from human gastric biopsy, Helicobacter pylori is responsible for gastritis, peptic ulcer, and gastric cancer. A pathogenicity island acquired by horizontal transfer, coding for a type IV secretion system, is a major determinant of virulence. The infection is now treated with antibiotics, and vaccines are in preparation. The geographic distribution suggests coevolution of man and Helicobacter pylori.

                Author and article information

                J Exp Med
                The Journal of Experimental Medicine
                The Rockefeller University Press
                1 May 2000
                : 191
                : 9
                : 1467-1476
                [a ]Centro Consiglio Nazionale Ricerche Biomembrane and Dipartimento di Scienze Biomediche, Università di Padova, 35121 Padova, Italy
                [b ]Centro di Ricerche IRIS, Chiron Vaccines Sp.A., 53100 Siena, Italy
                [c ]Dipartimento di Patologia Generale, Università di Verona, 37134 Verona, Italy
                [d ]Department of Clinical Medicine, Trinity College, Dublin 8, Ireland
                © 2000 The Rockefeller University Press
                Original Article


                nadph oxidase, monocytes, helicobacter, neutrophils, chemotaxis


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