| Autor: |
Lemos TJDS; Laboratório de Bacteriologia, Instituto Butantan, Avenida Vital Brasil, 1500, São Paulo 05503-900, SP, Brazil., Silva HGS; Laboratório de Bacteriologia, Instituto Butantan, Avenida Vital Brasil, 1500, São Paulo 05503-900, SP, Brazil., Previato JO; Instituto de Biofísica Carlos Chagas Filho, UFRJ, Avenida Carlos Chagas Filho, 373, Cidade Universitária, Rio de Janeiro 21941-902, RJ, Brazil., Mendonça-Previato L; Instituto de Biofísica Carlos Chagas Filho, UFRJ, Avenida Carlos Chagas Filho, 373, Cidade Universitária, Rio de Janeiro 21941-902, RJ, Brazil., Freitas EO; Instituto de Biofísica Carlos Chagas Filho, UFRJ, Avenida Carlos Chagas Filho, 373, Cidade Universitária, Rio de Janeiro 21941-902, RJ, Brazil., Barbosa AS; Laboratório de Bacteriologia, Instituto Butantan, Avenida Vital Brasil, 1500, São Paulo 05503-900, SP, Brazil., Franzolin MR; Laboratório de Bacteriologia, Instituto Butantan, Avenida Vital Brasil, 1500, São Paulo 05503-900, SP, Brazil., Santos LFD; Centro de Bacteriologia, Núcleo de Doenças Entéricas, Instituto Adolfo Lutz, Avenida Dr. Arnaldo, 355, São Paulo 01246-000, SP, Brazil., Melo BS; Laboratório de Bacteriologia, Instituto Butantan, Avenida Vital Brasil, 1500, São Paulo 05503-900, SP, Brazil., Anjos GFD; Laboratório de Bacteriologia, Instituto Butantan, Avenida Vital Brasil, 1500, São Paulo 05503-900, SP, Brazil., Gonçalves RHN; Laboratório de Bacteriologia, Instituto Butantan, Avenida Vital Brasil, 1500, São Paulo 05503-900, SP, Brazil., Domingos MO; Laboratório de Bacteriologia, Instituto Butantan, Avenida Vital Brasil, 1500, São Paulo 05503-900, SP, Brazil. |
| Abstrakt: |
Enteropathogenic Escherichia coli (EPEC) produce a capsule of polysaccharides identical to those composing the O-antigen polysaccharide of its LPS (lipopolysaccharide) molecules. In light of this, the impact of O26 polysaccharides on the immune evasion mechanisms of capsulated O26 EPEC compared to non-capsulated enterohemorrhagic Escherichia coli (EHEC) was investigated. Our findings reveal that there was no significant difference between the levels in EPEC and EHEC of rhamnose (2.8:2.5), a molecule considered to be a PAMP (Pathogen Associated Molecular Patterns). However, the levels of glucose (10:1.69), heptose (3.6:0.89) and N-acetylglucosamine (4.5:2.10), were significantly higher in EPEC than EHEC, respectively. It was also observed that the presence of a capsule in EPEC inhibited the deposition of C3b on the bacterial surface and protected the pathogen against lysis by the complement system. In addition, the presence of a capsule also protected EPEC against phagocytosis by macrophages. However, the immune evasion provided by the capsule was overcome in the presence of anti-O26 polysaccharide antibodies, and additionally, these antibodies were able to inhibit O26 EPEC adhesion to human epithelial cells. Finally, the results indicate that O26 polysaccharides can generate an effective humoral immune response, making them promising antigens for the development of a vaccine against capsulated O26 E. coli. |
