Navegando por Palavras-chave "intimin"

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    Acquisition of Serum Antibodies Reactive With Enterohemorrhagic Escherichia coli Virulence-Associated Factors by Healthy Brazilian Children and Adults
    (Lippincott Williams & Wilkins, 2009-12-01) Palmeira, Patricia; Carbonare, Solange B.; Guth, Beatriz E. C. [UNIFESP]; Carbonare, Cristiane B.; Pontes, Gerlandia N.; Tino-De-Franco, Milene; Zapata-Quintanilla, Lucy B.; Carneiro-Sampaio, Magda; Universidade Federal de São Paulo (UNIFESP); Butantan Inst
    Background: Patients with hemorrhagic colitis or hemolytic uremic syndrome due to enterohemorrhagic Escherichia coli (EHEC) develop serum IgM and IgG response to lipopolysaccharide (LPS) and to virulence factors such as intimin. the small numbers of cases of diarrhea associated with EHEC strains in Brazil suggests a pre-existing immunity probably due to previous contact with diarrheagenic E. coli. Our aim was to evaluate the development of the serum antibody repertoire to EHEC virulence factors in Brazilian children and adults.Methods: Serum IgM and IgG antibodies were determined by enzyme-linked immunosorbent assay with LPS O111, LPS O26, and LPS O157 in 101 children between 2 months and 10 years of age and in 100 adult sera, by immunoblotting with protein membrane extracts and purified beta intimin; the ability of adult sera to neutralize Shiga toxin2 was also investigated.Results: Children older than 24 months had IgM concentrations reactive with the 3 LPS equivalent to those seen in the adult group, and significantly higher than the group of younger children (P < 0.05). Anti-O26 and anti-O157 LPS IgG concentrations were equivalent between the 2 groups of children and were significantly different from the adult group (P < 0.05). the anti-O111 LPS IgG levels in older children were intermediate between the younger group, and adults (P < 0.05). Immunoblotting revealed strong protein reactivity, including the conserved and variable regions of beta intimin and more than 50% of the adult samples neutralized Shiga toxin 2.Conclusions: Our results demonstrate an increasing anti-LPS and antiprotein antibody response with age, which could provide protection against EHEC infections.
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    HeLa-cell adherence patterns and actin aggregation of enteropathogenic Escherichia coli (EPEC) and Shiga-toxin-producing E. coli (STEC) strains carrying different eae and tir alleles
    (Viguera Editores, S L, 2009-12-01) Mora, Azucena [UNIFESP]; Blanco, Miguel; Yamamoto, Denise [UNIFESP]; Dahbi, Ghizlane; Blanco, Jesus E.; Lopez, Cecilia; Alonso, Maria P.; Vieira, Monica A. M. [UNIFESP]; Hernandes, Rodrigo T. [UNIFESP]; Abe, Cecilia Mari [UNIFESP]; Piazza, Roxane M. F.; Lacher, David W.; Elias Junior, Waldir Pereira [UNIFESP]; Gomes, Tania Aparecida Tardelli [UNIFESP]; Blanco, Jorge; Univ Santiago de Compostela; Universidade Federal de São Paulo (UNIFESP); Butantan Inst; Calde Xeral Hosp; US FDA
    A collection of 69 eae-positive strains expressing 29 different intimin types and eight fir alleles was characterized with respect to their adherence patterns to HeLa cells, ability to promote actin accumulation in vitro, the presence of bfpA alleles in positive strains, and bundle-forming pilus (BFP) expression. All of the nine typical enteropathogenic Escherichia coli (tEPEC) studied harbored the enteropathogenic E. coli adherence factor (EAF) plasmid, as shown by PCR and/or EAF probe results. in addition, they were positive for bfpA, as shown by PCR, and BFP expression, as confirmed by immunofluorescence (IFL) and/or immunoblotting (IBL) assays. Localized adherence (LA) was exclusively displayed by those nine tEPEC, while localized-adherence-like (LAL) was the most frequent pattern among atypical EPEC (aEPEC) and Shiga-toxin-producing E. coli (STEC). All LA and LAL strains were able to cause attaching and effacing (AE) lesions, as established by means of the FAS test. There was a significant association between the presence of tir allele alpha 1 and bfpA-positive strains, and consequently, with the LA pattern. However, intimin type or bfpA was not associated with the adherence pattern displayed in HeLa cells. Among the eight bfpA alleles detected, a new type (beta 10; accession number FN391178) was identified in a strain of serotype O157:H45, and a truncated variant (beta 3.2-t; accession number FN 39118 1) in four strains belonging to different pathotypes. [Int Microbiol 2009; 12(4):243-251]