• Parasites, Hosts and Diseases
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• v.35 no.1
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• pp.47-54
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• 1997

It is generally accepted that parasite-specific IgE plays a crucial role in host defense against helminthic parasites. However, the role of high levels of nonspecific IgE in helminthic infections is still controversial. To investigate the role of nonspecific IgE in primary infections with P. westemani the effect of anti-lgE mAb treatment on serum IgE, $Fc{\varepsilon}RII/CD23$ expression and worm burden in Parcgonimus-infected mice were examined. In mice treated with anti-lgE antibody, the total IgE levels were not detectable ($1{\;}{\mu\textrm{g}/ml}$) throughout the experiment compared with untreated infected mice. The mean percentages of $Fc{\varepsilon}RII/CD23$ positive splenic B cells in anti-lgE treated mice (ridge: 20.3 - 30.5) were also decreased throughout the experiment compared with untreated infected mice (range: 35.7-44.4). Reduction of the total IgE and expression of $Fc{\varepsilon}RII/CD23$ on splenic B cells resulted in decreased worm burden six weeks post infection. These results suggest that high levels of nonspecific IgE in mice with primary infections of P. westemnni play a harmful, rather than beneficial, role for the host, perhaps by interfering with CD23-dependent cellular pathways.