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.
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.
Cai
Kun
K
State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Microbiology and Epidemiology, No. 20 Dongdajie, Fengtai District, Beijing 100071, P.R. China.
Gao
Xiang
X
Li
Tao
T
Hou
Xiaojun
X
Wang
Qin
Q
Liu
Hao
H
Xiao
Le
L
Tu
Wei
W
Liu
Yuenan
Y
Shi
Jing
J
Wang
Hui
H
D018829:Adhesins, Bacterial / Q000276:immunology; D000818:Animals; D001428:Bacterial Vaccines / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D019453:Escherichia coli O157 / Q000276:immunology*; D029968:Escherichia coli Proteins / Q000276:immunology; D007111:Immunity, Cellular / Q000276:immunology; D056724:Immunity, Humoral / Q000276:immunology; D007117:Immunization, Secondary; D007070:Immunoglobulin A / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D051379:Mice; D013601:T-Lymphocytes / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology*
D018829:Adhesins, Bacterial; D001428:Bacterial Vaccines; D029968:Escherichia coli Proteins; D007070:Immunoglobulin A; D007074:Immunoglobulin G; C073819:eaeA protein, E coli