IgE is known to enhance some antibody responses to specific
antigens, but whether this contributes to allergic
asthma remains unclear. We have previously found that repeated
antigen challenges in mice sensitized with
antigen-specific
IgE monoclonal antibody (mAb) exacerbated airway
inflammation and remodelling accompanied by increased levels of endogenous
antigen-specific
IgE and
IgG1. Here, we investigated whether
IgE/
antigen-mediated enhancement of endogenous
IgE production contributes to the exacerbation of airway
inflammation and remodelling. BALB/c mice passively sensitized with
ovalbumin (OVA) -specific
IgE mAb were challenged with OVA intratracheally seven times;
anti-IgE mAb was intraperitoneally administered 1 day before the fourth challenge. Treatment with
anti-IgE mAb inhibited the increased level of endogenous OVA-specific
IgE in serum, but not OVA-specific
IgG1, and a biphasic increase in airway resistance at the fourth challenge. Furthermore, a biphasic increase in airway resistance,
airway hyper-responsiveness to
methacholine, OVA-specific
IgE and
IgG1 production, and infiltrations by neutrophils and eosinophils in the lungs at the seventh challenge were suppressed by treatment;
airway remodelling, such as goblet cell
hyperplasia and sub-epithelial
fibrosis, was also reduced. In addition, the production of
interleukin-17A,
interleukin-33 and CXCL1 in the lungs related to these
IgE-mediated responses was decreased by treatment. Collectively, we found that the mechanism leading to the exacerbation of allergic
asthma is closely related to
IgE/
antigen-mediated enhancement of
IgE production, suggesting that this may create a vicious circle leading to the chronic status in asthmatic patients having levels of
antigen-specific
IgE ready to form complexes with
antigen.