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Comment
. 2000 May 1;191(9):1451-4.
doi: 10.1084/jem.191.9.1451.

Modulating phagocyte activation: the pros and cons of Helicobacter pylori virulence factors

L A Allen  1
Affiliations
Comment

Modulating phagocyte activation: the pros and cons of Helicobacter pylori virulence factors

L A Allen. J Exp Med. .
No abstract available

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Figures

Figure 1
Figure 1
Modulation of Hp–phagocyte interactions by HP-NAP, urease, and other virulence factors. (A) Type I/HP-NAP+/surface urease+ organisms. Surface urease (blue dimers) prevents opsonization with C3 and antibodies (red circles and Ys), thereby preventing phagocytosis via FcRs (white rectangles) and CR3 (gray dimers). An unidentified protein (green squares) allows Hp to bind tightly to the phagocyte via an unidentified receptor (light purple squares). Signaling from this receptor induces phagocytosis after a delay of several minutes. Meanwhile, HP-NAP (pink hexagons), and perhaps free NAP released after bacterial lysis, engage a G protein–coupled receptor (yellow circles) triggering translocation of p47/p67/p47phox (dark pink circles) to the plasma membrane by a Src and phosphatidylinositol 3-kinase–dependent mechanism (reference 4). Ammonia generated by urease and superoxide generated by the assembled NADPH oxidase (dark pink) damage host tissue. After ingestion and phagosome–phagosome fusion, Hp persist inside megasomes that resist fusion with lysosomes (reference 6). Mb., membrane. (B) Type II/HP-NAP−/surface urease− organisms. In the absence of surface urease and NAP, Hp is rapidly phagocytosed after opsonization with C3 and IgG, and does not stimulate oxidase assembly at the plasma membrane. Activation of protein kinase Cα (PKCα) downstream of FcRs and CR3 stimulates NADPH oxidase assembly on the phagosome and subsequent phagosome–lysosome fusion (references 22, 23). Megasomes do not form, and Hp is killed and digested in phagolysosomes. cyto., cytoplasm.
Figure 1
Figure 1
Modulation of Hp–phagocyte interactions by HP-NAP, urease, and other virulence factors. (A) Type I/HP-NAP+/surface urease+ organisms. Surface urease (blue dimers) prevents opsonization with C3 and antibodies (red circles and Ys), thereby preventing phagocytosis via FcRs (white rectangles) and CR3 (gray dimers). An unidentified protein (green squares) allows Hp to bind tightly to the phagocyte via an unidentified receptor (light purple squares). Signaling from this receptor induces phagocytosis after a delay of several minutes. Meanwhile, HP-NAP (pink hexagons), and perhaps free NAP released after bacterial lysis, engage a G protein–coupled receptor (yellow circles) triggering translocation of p47/p67/p47phox (dark pink circles) to the plasma membrane by a Src and phosphatidylinositol 3-kinase–dependent mechanism (reference 4). Ammonia generated by urease and superoxide generated by the assembled NADPH oxidase (dark pink) damage host tissue. After ingestion and phagosome–phagosome fusion, Hp persist inside megasomes that resist fusion with lysosomes (reference 6). Mb., membrane. (B) Type II/HP-NAP−/surface urease− organisms. In the absence of surface urease and NAP, Hp is rapidly phagocytosed after opsonization with C3 and IgG, and does not stimulate oxidase assembly at the plasma membrane. Activation of protein kinase Cα (PKCα) downstream of FcRs and CR3 stimulates NADPH oxidase assembly on the phagosome and subsequent phagosome–lysosome fusion (references 22, 23). Megasomes do not form, and Hp is killed and digested in phagolysosomes. cyto., cytoplasm.
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Comment on

References

    1. Covacci A., Telford J.L., Del Giudice G., Parsonnet J., Rappuoli R. Helicobacter pylori virulence and genetic geography. Science. 1999;284:1328–1333. - PubMed
    1. Evans D.J., Jr., Evans D.G., Takemura T., Nakano H., Lambert H.C., Graham D.Y., Granger D.N., Kvietys P.R. Characterization of a Helicobacter pylori neutrophil-activating protein. Infect. Immun. 1995;63:2213–2220. - PMC - PubMed
    1. Tonello F., Dundon W.G., Satin B., Molinari M., Togon G., Grandi G., Del Giudice G., Rappuoli R., Montecucco C. The Helicobacter pylori neutrophil-activating protein is an iron-binding protein with dodecameric structure. Mol. Microbiol. 1999;34:238–246. - PubMed
    1. Satin B., Del Giudice G., Della Bianca V., Dusi S., Laudanna C., Tonello F., Kelleher D., Rappuoli R., Montecucco C., Rossi F. The neutrophil-activating protein (HP-NAP) of Helicobacter pylori is a protective antigen and a major virulence factor. J. Exp. Med. 2000;191:1467–1476. - PMC - PubMed
    1. Xiang Z., Censini S., Bayeli P.F., Telford J.L., Figura N., Rappuoli R., Covacci A. Analysis of expression of CagA and VacA virulence factors in 43 strains of Helicobacter pylori reveals that clinical isolates can be divided into two major types and that CagA is not necessary for expression of the vacuolating cytotoxin. Infect. Immun. 1995;63:94–98. - PMC - PubMed

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