題組內容

V.
　Escherichia coli Vacuolating Factor (ECVF) is a heat-labile,vacuolating cytotoxin produced by avian pathogenic E. coli (APEC)isolated from avian cellulitis lesions. In this report, we intend todemonstrate that purified ECVF induces the inflammatory processof cellulitis. Our group is the first to demonstrate the effect ofECVF in a histological analysis by in situ inoculation of broilerchickens with purified ECVF. The animals were inoculated with theAPEC AC53 and with purified ECVF subcutaneously on theirventral surface (in the sternum region). The histological analysisshowed different grades of an acute inflammatory response in theepidermis, dermis and panniculus. An increase in mRNAexpression of the proinflammatory cytokine TNF-a was also demonstrated in the inflamed tissue. When ECVF was systemicallyadministered, increased levels of TNF-a and IL-10 were observedin the serum. These results suggest that ECVF plays a key role inthe inflammatory process associated with cellulitis that is mainlymediated by TNF-a. In addition, this inflammation can bedownregulated by the anti-inflammatory cytokine IL-10.