Abstract:
:Cytotoxic necrotizing factor type 1 (CNF1) and CNF2 are toxins of pathogenic Escherichia coli that share 85% identity over 1,014 amino acids. Although both of these toxins modify GTPases, CNF1 is a more potent inducer of multinucleation in HEp-2 cells, binds more efficiently to HEp-2 cells, and, despite the conservation of amino acids (C866 and H881) required for enzymatic activity of the toxins, deamidates RhoA and Cdc42 better than CNF2. Here we exploited the differences between CNF1 and CNF2 to define the epitope on CNF1 to which the CNF1-specific neutralizing monoclonal antibody (MAb) (MAb NG8) binds and to determine the mechanism by which MAb NG8 neutralizes CNF1 activity on HEp-2 cells. For these purposes, we generated a panel of 21 site-directed mutants in which amino acids in CNF1 were exchanged for the amino acids in CNF2 between amino acids 546 and 869 and vice versa. This region of CNF1 not only is recognized by MAb NG8 but also is involved in binding of this toxin to HEp-2 cells. All the mutants retained the capacity to induce multinucleation of HEp-2 cells. However, the CNF1 double mutant with D591E and F593L mutations (CNF1(D591E F593L)) and the CNF1(H661Q) single mutant displayed drastically reduced reactivity with MAb NG8. A reverse chimeric triple mutant, CNF1(E591D L593F Q661H), imparted MAb NG8 reactivity to CNF2. MAb NG8 neutralized CNF2(E591D L593F Q661H) activity in a dose-dependent manner and reduced the binding of this chimeric toxin to HEp-2 cells. Taken together, these results pinpoint three amino acids in CNF1 that are key amino acids for recognition by neutralizing MAb NG8 and further help define a region in CNF1 that is critical for full toxin binding to HEp-2 cells.
journal_name
Infect Immunjournal_title
Infection and immunityauthors
Grande KK,Meysick KC,Rasmussen SB,O'Brien ADdoi
10.1128/IAI.00943-08subject
Has Abstractpub_date
2009-01-01 00:00:00pages
170-9issue
1eissn
0019-9567issn
1098-5522pii
IAI.00943-08journal_volume
77pub_type
杂志文章abstract::The pathogenesis of middle ear inflammation caused by Streptococcus pneumoniae was explored in the chinchilla model with different pneumococcal cell wall (CW) preparations, including isolated native CW, M1 muramidase CW (M1-CW) digest, amidase CW digest, and M1 peptidoglycan (M1-PG) digest. Inflammatory cell and lysoz...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.60.7.2850-2854.1992
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journal_title:Infection and immunity
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doi:10.1128/IAI.67.8.3793-3799.1999
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journal_title:Infection and immunity
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doi:10.1128/IAI.25.3.820-827.1979
更新日期:1979-09-01 00:00:00
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pub_type: 杂志文章
doi:10.1128/IAI.01230-13
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pub_type: 杂志文章
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journal_title:Infection and immunity
pub_type: 杂志文章
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.56.5.1076-1083.1988
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journal_title:Infection and immunity
pub_type: 杂志文章
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更新日期:1982-01-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.34.2.469-477.1981
更新日期:1981-11-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.21.3.1003-1009.1978
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journal_title:Infection and immunity
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doi:10.1128/IAI.00890-16
更新日期:2016-12-29 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00041-07
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.63.7.2780-2784.1995
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00161-15
更新日期:2015-07-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.43.2.531-535.1984
更新日期:1984-02-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.64.7.2415-2419.1996
更新日期:1996-07-01 00:00:00
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journal_title:Infection and immunity
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journal_title:Infection and immunity
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pub_type: 杂志文章
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更新日期:1978-03-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.5.2.238-247.1972
更新日期:1972-02-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
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更新日期:2001-03-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.52.1.1-5.1986
更新日期:1986-04-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.62.11.5075-5084.1994
更新日期:1994-11-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.60.4.1390-1396.1992
更新日期:1992-04-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.55.8.1762-1766.1987
更新日期:1987-08-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.59.10.3823-3826.1991
更新日期:1991-10-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.5.2.232-237.1972
更新日期:1972-02-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.59.7.2316-2323.1991
更新日期:1991-07-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.15.2.453-460.1977
更新日期:1977-02-01 00:00:00