| Autor: |
Silva HGS; Laboratório de Bacteriologia, Instituto Butantan, Avenida Vital Brasil, 1500, São Paulo CEP 05503-900, SP, Brazil., Franzolin MR; Laboratório de Bacteriologia, Instituto Butantan, Avenida Vital Brasil, 1500, São Paulo CEP 05503-900, SP, Brazil., Anjos GFD; Laboratório de Bacteriologia, Instituto Butantan, Avenida Vital Brasil, 1500, São Paulo CEP 05503-900, SP, Brazil., Barbosa AS; Laboratório de Bacteriologia, Instituto Butantan, Avenida Vital Brasil, 1500, São Paulo CEP 05503-900, SP, Brazil., Santos LFD; Centro de Bacteriologia, Núcleo de Doenças Entéricas, Instituto Adolfo Lutz, Avenida Dr. Arnaldo, 355, São Paulo CEP 01246-000, SP, Brazil., Miranda KF; Laboratório de Bacteriologia, Instituto Butantan, Avenida Vital Brasil, 1500, São Paulo CEP 05503-900, SP, Brazil., Marques RM; Laboratório de Bacteriologia, Instituto Butantan, Avenida Vital Brasil, 1500, São Paulo CEP 05503-900, SP, Brazil., Souza MCL; Laboratório de Bacteriologia, Instituto Butantan, Avenida Vital Brasil, 1500, São Paulo CEP 05503-900, SP, Brazil., Piazza RMF; Laboratório de Bacteriologia, Instituto Butantan, Avenida Vital Brasil, 1500, São Paulo CEP 05503-900, SP, Brazil., Domingos MO; Laboratório de Bacteriologia, Instituto Butantan, Avenida Vital Brasil, 1500, São Paulo CEP 05503-900, SP, Brazil. |
| Abstrakt: |
The serogroup O55 of E. coli is composed of strains whose mechanisms of virulence are different from each other. Since the O55 polysaccharides are present in all E. coli O55 strains, and so are the polymers that compose the capsule of O55 atypical enteropathogenic E. coli (aEPEC), it was investigated whether anti-O55 antibodies were able to help the innate immune system to eliminate capsulated aEPEC and Shiga toxin-producing E. coli (STEC) belonging to the serogroup O55. The results demonstrate that the capsule of EPEC was able to inhibit the deposition of C3b on the bacterial surface and, as a consequence, their lysis by the alternative pathway of the complement system. However, in the presence of antibodies, the ability of the complement to lyse these pathogens was restored. It was also observed that macrophages were able to ingest EPEC and STEC, but they were only able to kill the ingested pathogens in the presence of antibodies. Anti-O55 antibodies were also able to inhibit aEPEC and STEC O55 adherence to human epithelial cells. In summary, the results demonstrated that the O55 polysaccharides have the potential to induce an effective humoral immune response against STEC and EPEC, indicating that they are good antigen targets to be used in vaccine formulations against these pathogens. |
