Intragastric immunization of mice with enterohemorrhagic Escherichia coli O157:H7 bacterial ghosts reduces mortality and shedding and induces a Th2-type dominated mixed immune response

Can J Microbiol. 2010 May;56(5):389-98. doi: 10.1139/w10-025.

Abstract

A bacterial ghost (BG)-based vaccine was developed against enterohemorrhagic Escherichia coli O157:H7 infection. The aim of this study was to evaluate the protective effect of E. coli O157:H7 BGs in a mouse model and to reveal the mechanism of the immune response. Booster immunization provided a higher protection rate (84%) than single-dose immunization (56%). Intragastric immunization of E. coli O157:H7 BGs induced both humoral and cellular immune responses. The proliferative response of CD4+ T cells was mediated by the antigen-presenting cells. The humoral immune response dominated the immune response, while the cellular immune response developed later. Inflammatory reaction was balanced by the mixed Th1/Th2 immune response. The immune sera anti-adhesion effect was confirmed by the inhibition effect, which could inhibit >90% of the adhesion of E. coli O157:H7 to Hep-2 target cells in vitro. Antibody titer specific for intimin, a molecule important for adhesion of E. coli O157:H7 to target cells, correlated with specific immunoglobulin A or G antibody titer. Therefore, it might be feasible to clinically test BG vaccines in the future.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adhesins, Bacterial / immunology
  • Animals
  • Bacterial Vaccines / immunology*
  • CD4-Positive T-Lymphocytes / immunology
  • CD8-Positive T-Lymphocytes / immunology
  • Escherichia coli O157 / immunology*
  • Escherichia coli Proteins / immunology
  • Immunity, Cellular / immunology
  • Immunity, Humoral / immunology
  • Immunization, Secondary
  • Immunoglobulin A / immunology
  • Immunoglobulin G / immunology
  • Mice
  • T-Lymphocytes / immunology
  • Th2 Cells / immunology*

Substances

  • Adhesins, Bacterial
  • Bacterial Vaccines
  • Escherichia coli Proteins
  • Immunoglobulin A
  • Immunoglobulin G
  • eaeA protein, E coli